Category Archives: Engineering

Summer Engineering Intern Shares Positive Experiences From Time at ATS

Vlad Blyakhman, a rising sophomore in the School of Engineering and Applied Sciences at George Washington University (Washington, D.C.), sat down with the marketing team to speak about his experiences as a summer intern at Advanced Thermal Solutions, Inc. (ATS).

Engineering Intern

George Washington University rising sophomore Vlad Blyakhman spent the summer as an engineering intern at ATS. (Advanced Thermal Solutions, Inc.)

After a summer working in the ATS labs, learning about the company’s wide range of thermal management products, from heat sinks for convection cooling to its liquid cooling options, and exploring thermal engineering topics with the ATS staff, Vlad is now ready to continue his mechanical engineering studies at GW this fall.

“Before I came here,” Vlad explained, “I just knew it was engineering that had to do with heat, but now I understand that it’s obviously a lot more than that.”

He added, “When I first got to ATS, I remember just being in the lab and seeing these crazy machines and having no idea what they’re for or what they do, but now, after spending some time here, I can go back in the same laboratory and know that I know how to use them and know what they do now.”

According to Vlad, his favorite part of his summer at ATS was creating and designing a fixture for testing cold plates in the lab. He also had the opportunity to see ATS engineers in action, watching them at work developing designs for customers and working on the next generation of thermal management solutions. It was a chance to put his classroom learning into practice and expand his knowledge base beyond what he had studied to this point.

When asked if he would recommend an ATS internship to another student, Vlad said, “It’s a very specific experience that you can’t get anywhere else. So, I think it will really help you decide what field you want to go into; what type of engineering.”

Here more from Vlad in the full video below:

For more information about Advanced Thermal Solutions, Inc. (ATS) thermal management consulting and design services, visit www.qats.com/consulting or contact ATS at 781.769.2800 or ats-hq@qats.com.

Heat Sink Design: ATS Engineers Bring Ideas to Life

Marketing Communications Specialist Josh Perry sat down with Product Engineering Manager Greg Wong to discuss the process that Advanced Thermal Solutions, Inc. (ATS) engineers go through to create a heat sink and find a thermal solution for customers.

Watch the full conversation in the video below and scroll down to read the transcript of the interview.

JP: Greg, thanks again for joining us here in marketing to explain what it is that goes into designing a heat sink for a customer. So, how does that process begin?
GW: We usually start with a few basic parameters; we call them boundary conditions. So, we start with a few boundary conditions, basics like how much airflow we have, how much space constraint we have around a heat sink, and how much power we’re dissipating, as well as the ambient temperature of the air coming into the heat sink.

So, those are the real basic parts that we need to start out with and sometimes the customer has that information and they give it to us, and usually we double-check too, and then other times the customer has parts of the information, like they know what fan they want to use and they know what kind of chassis they’re putting it in and we take that information and we come up with some rough calculations so we can arrive at those things like air flow and stuff like that.

JP: When you get the data from the customer, how do you determine what the problem is, so that way you can move forward?
GW: We usually start out with an analytical analysis. So, we put pen to paper and we start out with basic principles of heat transfer and thermal resistance and stuff like that so we can understand if what we’re trying to achieve is even feasible and we can come up with some basic parameters just using that analytical analysis.

Like we can calculate what kind of heat sink thermal resistance we need or we can calculate how much air flow we need or, if we have several components in a row, we can calculate what the rough air temperature rise is going to be along that chain of parts. So, there’s a lot we can do when we get the basic information from the customer just on pen and paper.

JP: What’s the next step beyond analytical?
GW: Well, we can do some lab testing or a lot of times we also use CFD simulations and, if our customer has a model they can supply us, we can plug that into the CFD simulations and we can come up with an initial heat sink design and we can put that into the simulations as well and then we set those up and run them.

The great thing, having done these analytical analyses beforehand, we know what to expect from CFD simulations. So that way, if the simulations don’t run quite right, we already have an understanding of the problem, we know what to expect, because CFD is not 100 percent reliable.

I mean, you can go and plug all this stuff in there but you really have to understand the problem to know if the CFD is giving you a good result. So, oftentimes that’s the next stage of the process and from there we can actually produce low-volume prototypes right here in Norwood (Mass.), in our factory. We have CNC machines and manual milling machines, lathes, all that kind of stuff, and we can produce the prototypes and test them out here in our labs.

JP: How much of a benefit is it to be able to create a prototype and to be able to turn one around quickly like that?
GW: Oh, it’s great. I mean, if we had to wait to get parts from China it will take weeks to get. We can turn them around here in a few days and the great thing about that is we can test them in our labs and, you know, when it comes to getting results nothing beats the testing.

I mean, you can do analytical analysis, you can do CFD simulations, but when you actually test the part in a situation that is similar to what the actual thing is going to be that’s where the real meat comes down.

Heat Sink Design

ATS engineers take customer data and using analytical modeling and CFD simulations can design the right cooling solution to meet the customer’s specific thermal needs. (Advanced Thermal Solutions, Inc.)

JP: So, we test the prototypes before sending them out to the customer? We do the testing here or do we send it to them first?
GW: It all depends on what the customer requires. Sometimes the customer has a chassis that we really can’t simulate in our labs, so we might send the prototype heat sinks to the customer and the customer will actually put them into their system to test them out.

Other times, a customer might have a concept and they don’t actually have a product yet, so we’ll mock something up in our labs and we’ll test it and it all just depends what the customer needs and also how complex the problem is.

If it’s a simple heat sink and pretty simple airflow, we might not need to test that because we understand that pretty well, but the more complex the chassis is and how the airflow bends and stuff like that, the greater benefits we get out of lab testing.

JP: Well, I appreciate it Greg. Thank you for taking us through the process of making a heat sink and solving thermal problems for our customers.
GW: Sure Josh. We love seeing new thermal challenges and coming up with ways of keeping stuff cool.

For more information about Advanced Thermal Solutions, Inc. thermal management consulting and design services, visit www.qats.com or contact ATS at 781.769.2800 or ats-hq@qats.com.

Industry Tips for Placing DC/DC Converters on PCB

DC/DC Converters

This article outlines industry tips and suggestions about placing DC/DC power converters on a PCB with other components. (Advanced Thermal Solutions, Inc.)

The design of a printed circuit board (PCB) that includes isolated DC to DC power converters is an important consideration to ensure the optimal performance of a system. Engineers have to be concerned with parasitic impedance and capacitance, the effects of the electromagnetic field created by the power converter on nearby components, as well as voltage accuracy, environmental noise reduction, and limiting radiated electro-magnetic interference (EMI).

This electromagnetic effect can cause significant voltage drops and improper design of a PCB could force engineers to make potentially costly changes (in terms of design time and budget), such as additional circuitry or upgrades to external components like power switches and capacitors.(i)

There are many advantages to using DC/DC converters and engineers adding these power bricks to a PCB do not have to be experts on power supply design, since the Distributed-power Open Systems Alliance (DOSA) has defined the industry standards for footprints and pinouts. Engineers know ahead of time how much space to dedicate and how the converter will be connected to the board.(ii)

“The brick typically comprises all the components (apart from filter circuits) required for a switching power supply including MOSFET switches, energy storage components, and switching controller,” writes Steven Keeping of Electronic Products on DigiKey.com. “By selecting a brick, an engineer does not have to worry about the intricacies of switching power supply design. The supplier has done all the work to ensure the unit operates optimally.”

While much of the work has been done by the manufacturer of the DC/DC converter to ensure its proper function, the engineer designing the system still has to consider the converter’s placement on a board carefully.

Parasitic Resistance, Impedance, and Capacitance

The most prominent issue that DC/DC converters can cause on a PCB is parasitic resistance, capacitance, and impedance. The power module creates an electromagnetic field that could disrupt the performance of components within its boundaries. As noted above, this could cause an unwanted voltage drop for the system and force more external power to be pushed through the converter.

According to a report published by members of the Institute of Electrical and Electronics Engineers (IEEE) from Georgia Tech University, “Short and wide routing traces have lower parasitic resistances and inductances and therefore superimpose less ill-fated effects to the system. As a result, to reduce the parasitic resistance and inductance, the first rule in PCB layout is to place connected power components as close as possible and in a way that their interconnection lengths are minimal.”(iii)

An article on DigiKey.com adds, “The signal traces should not be routed underneath the module, unless they are sandwiched between ground planes, to avoid noise coupling. Similarly, to prevent any coupling, no component should be placed under the module.”(iv)

The IEEE report continued, “Ground planes are effectively close high-speed return paths for average forward signal paths, but arbitrarily increasing the ground plane may not necessarily reach critical nodes. In PCB technologies with more than two layers, middle layers are normally dedicated to ground planes, thereby decreasing their distance to high-current forward switching paths.”

It also recommended using parallel connections for the supply ground, load ground, and measurement instrument’s ground rather than series connectors that are potentially unreliable and that can add impedance between nodes. The report stated, “Undesired noise and high temperature gradients across the PCB usually result when problems with supply ground connections exist.”

DC/DC converters regulate the voltage supply to the system from external power supplies, which makes accuracy a critical component of its performance. In order to ensure the optimal accuracy, it is recommended that the feedback sense terminal is connected as close to the load as possible. It is this voltage that will be converted.

(Advanced Thermal Solutions, Inc.)

Radiated Electromagnetic Interference

Another major concern for placing a DC/DC converter on a PCB is the amount of radiated electromagnetic interference (EMI) is emitted from the module. This is limited by industry standards (CISPR in Europe and FCC in the U.S.) but, as converters work by converting input voltage to AC before converting it back to DC at the correct voltage, there is an electromagnetic field that is produced when the converter is in use.

To minimize the effects of this EMI, “High-frequency nodes should be as short as possible. The metal paths act as antennas and their frequency range is directly proportional to their length. High frequency signal-return paths should be as close as possible to their respective forward paths. The two traces will therefore generate equal but opposite magnetic fields, canceling each other and hence reducing radiated EMI.”(v)

Tim Hegarty, writing for EDN Network, said, “A passive shield layer is established by placing a ground plane as close as possible to the switching loop by using a minimum dielectric thickness. The horizontal current flow on the top layer sets up a vertical flux pattern. The resulting magnetic field induces a current, opposite in direction to the power loop, in the shield layer.

“By Lenz’s Law, the current in the shield layer generates a magnetic field to counteract the original power loop’s magnetic field. The result is an H-field self-cancellation that amounts to lower parasitic inductance, reduced switch-node voltage overshoot, and enhanced suppression of EMI. Having an uninterrupted, continuous shield plane on layer 2 underneath and at closest proximity to the power loop offers the best performance.”(vi)

On DigiKey.com, Steve Taranovich of Electronic Products Magazine wrote, “The input of a DC/DC power module is a constant power at low frequencies. As the voltage decreases, current increases. This will present negative impedance at the input source. The converter will oscillate when the combination of the input filter’s impedance and the power module impedance becomes negative, causing a mismatch to occur. One way to prevent this is to ensure that the output impedance of the filter is much smaller than the input impedance of the power module at all frequencies.”(vii)

Another issue related to electromagnetic field is ground bounce, which is produced by changing magnetic flux due to the fast-changing currents. One of the solutions to prevent this problem, which could cause noise in video and audio devices, is to ensure that “true ground” is at the low end of the load and that all the other points are part of the ground return. In a two-layer PCB, Jeff Barrow of Analog.com also suggests, “A well-planned cut in the ground plane will constrain the return current to a minimum loop area and greatly reduce the bounce. Any residual bounce voltage that is developed in the cut return line is isolated from the general ground plane.”(viii)

Conclusions

Industry standard DC/DC converters have made adding a power supply to a PCB easier for engineers in terms of known sizes and connections. The footprint of a power module is known, but engineers still have important considerations to make before deciding where it should be placed. Keeping in mind the effects of parasitic impedance, capacitance, and resistance and ensuring that the electromagnetic interference will not surpass industry standards or affect other components on the board will ensure optimal performance of the system as a whole.

Using the design tips that are listed here, engineers are well on their way to creating an effective PCB layout with a DC/DC converter. Using Advanced Thermal Solutions, Inc. (ATS) Power Brick heat sinks will ensure the proper thermal management of the converters and of the board.
Learn more about Power Brick heat sinks at https://www.qats.com/eShop.aspx?productGroup=0&subGroup=2&q=Power%20Brick.

For more information about Advanced Thermal Solutions, Inc. thermal management consulting and design services, visit www.qats.com or contact ATS at 781.769.2800 or ats-hq@qats.com.

References

i http://rincon-mora.gatech.edu/research/pcb.pdf
ii http://www.digikey.com/en/articles/techzone/2012/dec/an-introduction-to-board-mounted-dcdc-converter-bricks
iii http://rincon-mora.gatech.edu/research/pcb.pdf
iv http://www.digikey.com/en/articles/techzone/2012/jul/proper-pcb-layout-minimizes-noise-coupling-for-point-of-load-converter-modules
v http://rincon-mora.gatech.edu/research/pcb.pdf
vi http://www.edn.com/design/power-management/4439749/3/DC-DC-converter-PCB-layout–Part-2
vii http://www.digikey.com/en/articles/techzone/2011/dec/conducted-and-radiated-emissions-reduction-techniques-for-power-modules
viii https://pdfs.semanticscholar.org/e3bb/49a1403b2da7d3d77e7024f7be208ee3a732.pdf

Q&A: ATS Thermal Engineer Sridevi Iyengar

Sridevi Iyengar

ATS thermal and field application engineer Sridevi Iyengar does CFD modeling (like the one shown above) and on-site consulting for ATS from her location near Bangalore, India. (Advanced Thermal Solutions, Inc.)

Advanced Thermal Solutions, Inc. field application and thermal engineer Sridevi Iyengar recently spoke with Marketing Communications Specialist Josh Perry about her career in engineering and the work that she does for ATS. Iyengar works near her home in Bangalore, India and provides ATS with CFD simulations and on-site support for customers in the region.

In this Q&A, Iyengar speaks about why she became an engineer in the first place, how she came to work at ATS, the type of projects that she works on, the challenges that she faces as a woman in a male-dominated industry, and what it is like working halfway around the world from the engineers at ATS’ Norwood, Mass. campus.

JP: How did you get interested in engineering? How did it all start for you?
SI: I was a good student in high school and in college and my father is a metallurgical engineer. He was a professor in one of the premier institutes in India, the Indian Institute of Science. When we were at the crossroad, during 12th grade, honestly the bright students either went into medicine or engineering and since my math skills were pretty good and I’d been to the Indian Institute of Science a couple of times I had written the entrance examinations for both streams. For engineering, I got into a very good school.

Although I didn’t know about the different disciplines of engineering, I happened to go into chemical engineering because that’s what my rank got me into. I liked it because chemical is kind of a fusion between math and physical phenomena and so that’s where my engineering journey started.

After my Bachelor’s, I wanted to do higher studies. I got married and came to the United States and I wanted to continue in my field of study. I didn’t want to move into software like pretty much everybody else from India when they move to the U.S. I wanted to keep myself different and I had a lot of support for that from my family. The first place I set up home is Norwood, Mass. (in 1993). I was preparing for my GRE and contemplating whether I should take my AGRE but I got positive responses from a couple of schools that I was also keen on getting into. I had options. One was the University of Massachusetts – Lowell, one was Rutgers University and the University of California – San Diego. I chose San Diego.

I was actually accepted into the doctoral program, however at UC-San Diego I liked the fluid mechanics and heat transfer program but then I didn’t want to jump into a Ph. D. without really having real world experience. I wanted to finish my Master’s, work for a few years and then maybe come back if I was interested. Much to my disappointment of my dad, I dropped out of the doctorate program with my Master’s and entered the job scene.

My entry into thermal engineering was kind of by chance. My first job was with Structural Dynamics Research Corporation (SDRC) in San Diego. It was the advanced test and analysis group. I had a background in heat transfer and fluid mechanics and therefore I joined as an intern and they made me do a little bit of this and that. The software associated with the IDEAS master series for electronics cooling was MAYA-ESC electro-systems cooling and TMG (thermal model generator) and we did a project for Cisco Systems in the Bay Area. I worked for about a year and half at ATA-SDRC. SDRC was doing a lot of projects for defense and their core area was becoming more and more defense and I was not a U.S. citizen so it was very difficult for them to assign me to projects because I didn’t have security clearance. At that time I jumped ship and I joined Cisco Systems as a mechanical engineer.

JP: How did you hear about Advanced Thermal Solutions, Inc.? How did you end up working here?
SI: ATS, the company, I knew even when I was at Cisco back in 1999. I was with Cisco until 2005 and at that time I knew about Advanced Thermal Solutions because as a mechanical engineer my job was also to source heat sinks. Also, that it was based in Norwood kind of struck a chord and it remained in my mind. I had known a lot about [ATS CEO, President and founder] Dr. Kaveh Azar because a close colleague of mine had worked closely with Kaveh. And of course Qpedia Thermal eMagazine was/is a very useful online journal.

How I joined ATS was a very, very chance meeting. We moved back to India in 2009 and I was working for an aluminum extrusion company in their thermal management division. It’s a Swedish company called Sapa. Sapa opened an office in India and it was just the sales manager and myself in the Indian team when I started. I worked with Sapa for three years and I was working for their global application team, half working for Sweden and half trying to set up the market in India. At Sapa I did a little bit more than thermal management. Sapa acquired an extrusion facility and also had a machining/anodizing unit. I was exposed to various aspects of manufacturing with regards to aluminium extrusions, fabrication etc., and worked on several other projects, which needed someone who could work with the customers and the manufacturing team at Sapa – sort of like a liaison and the engineering hand of the sales person.

When I quit Sapa, I thought I would go freelance doing electronics cooling consulting and I met one of the sales channel partners for ATS and with him I went and met Dr. Kaveh and Shashwat Shashwat (ATS Product Realization Manager), who were visiting India. This was in May of 2014 and initially it was just supposed to be a ‘hello, how are you’ meeting, but then we started talking and having common professional contacts and interests made it a very interesting interaction. We had lunch and when I came back home that evening Shashwat called me and asked if I was interested in working for ATS. I had no doubts whether I would take this opportunity; I took it with both hands. It’s worked out very well for me so far.

JP: What kinds of projects are you working on for ATS?
SI: There were two things for me, the mandate. One was that we wanted to beef up our presence in India. We already had a sales presence and we were selling heat sinks through Digi-Key and if the engineers know what they want then it’s not a big deal, but it helps them so much to know that there is technical staff from ATS present in India and in Bangalore in the southern region. They call and they say, ‘We’re looking at this heat sink, do you think it’s okay?’ Otherwise they send an email and then they wait for Norwood to reply. So, my role was to support the local sales partners that we have. They do the initial sales call and everything, but then if there’s anything technical they can say, ‘You know, ATS has a presence here? We have this engineer who is in electronic cooling and she has experience.’ I’ve gone to several meetings with them.

Secondly, for the U.S. customers, when it comes to CFD simulations like FloTherm then I work very closely with Norwood. In fact, I’ve done quite a few projects with [ATS field application engineers] Greg Wong or Peter [Konstalilakis], Vineet [Barot] too. A lot of times there are CFD simulations, they face the customers, they get the answers and I run the simulation and build the models here, do the analysis, we discuss the results and they send it to the customer.

JP: Is there a lot of collaboration between yourself and the engineers here in Norwood?
SI: Almost daily. I am online pretty much every day from 6 and on Wednesdays and Fridays we have the team meeting. On other days, I usually chat up with my counterpart on the project and, if it’s a major project, then the discussion is fairly involved. A lot of times, I’ll have a lot of questions so I’ll contact my teammates during my evening and he’ll take it up with the customer, get all the questions answered and by the time morning rolls around everything is sent to me by email and I get through my day. There is a lot of collaboration.

JP: Looking at thermal engineering as a whole, where do you see the industry going?
SI: People realize the importance of up-front thermal design and these folks who are dealing with high-powered components are aware of the importance of up-front thermal design. However there are still a lot of projects in which the hardware engineers are still not zoned into thinking of up-front thermal management, it’s coming in as kind of a ‘Oh it’s too hot, let’s do something about it’ approach. However, I think that mindset is changing a lot and I think the next-gen heat sinks like vapor chambers, heat pipes, and nano-materials will really start making their appearance more and more in thermal solutions because we’re getting to a point where the run of the mill is not cutting it.

JP: Do you see that change coming fairly quickly? In this industry, it seems like things change every day.
SI: The mindset should change because there’s always an aversion towards liquid and PCB. The more we educate people and the fact that we see everything in liquid cooling systems working…It takes some time for them to know that, okay it is a fairly fail-safe method. It will take at least a year or two and it should be running at that time and then people will catch on. It’s not something that can be easily brought on, I think, because generally we know that liquids and electronic components don’t mix. To assure them that it will not mix and there’s no chance of it coming into contact, I think that’s the stumbling block.

It’s market education and also having systems out there functioning, so that we can show them it’s not just theoretical. You have systems in practice and I think that makes a difference. If we can show it in theory, it doesn’t help as much because in theory everything looks wonderful, so we need to show them in practice and all the possible problems that can come up have been addressed and it is working in the field not just in the test lab.

JP: As a woman in a predominantly male-dominated industry, has it been difficult at all?
SI: In India, even back in 1993, we had a lot of engineers who were graduating but a lot of them didn’t stay back in what I call hardcore engineering. People used to go into information technology because they thought somehow it was more suitable for the women in the workforce situation. But I personally, I’ve had a fulfilling time and it is good to distinguish yourself and be different. The work that we do at ATS is hardcore engineering and we have engineers to lead us. We have Dr. Kaveh Azar and Dr. Bahman Tavassoli who have years of engineering experience and yeah sometimes they come down hard on us but that’s because they know what they’re doing. They’ve been there, done that, and they want to extract the best out of you and they want you to think like an engineer always. That’s what is unique of working at ATS.

JP: Do you hope to inspire other women to not only join the field, but stick with the ‘hardcore’ engineering?
SI: Yeah, absolutely. There have been young women who have reached out to me, young engineers who graduated in India, and I tell them have patience and learn the skills needed to get a job. It’s very easy to learn a few programming languages and jump into IT, especially in India right now, but you’re going to be just like anybody else. If your heart really lies in engineering, you should stick on, network, upgrade your skills and you’ll definitely find a job. The first job is everything you need and after that, if you do well there, then the path is smooth.

JP: How has it been for you as a ‘distant worker’ in terms of not being located here in Norwood? We have a lot of great technology like Skype and GoToMeeting, how have you found it being a ‘distant worker’?
SI: Since I interact with the engineers on an almost daily basis it is not that different. ATS engineers and the customers are very understanding of the time difference and accommodate the meetings, if any, so that it is not totally at unearthly hours for me. I also have the freedom to have my own schedule and that is very helpful since I am a working mother. I’ve been to ATS once and so I have met most of the team there.

The only thing is that I don’t have that touch and feel. Sometimes the ATS engineers have the heat sinks/components on their desk and they’re looking at it. A lot of times they will look at it, turn it around and these are things that I will have to accomplish through video call on Skype or the engineers take pictures and send them to me. But it’s not the same. That’s the only drawback. And of course when you folks have your team lunches/picnics … I feel left out.

JP: From our conversation, it sounds like you really like challenging projects?
SI: I think we all like to be challenged once in a while. With involved models, one of the challenges was I’d have to remotely log in and run the model in the 12-core PC and ensure nobody is logged in and I used to run it through the night and post-process it via remote connection. I’d transfer the results over and make the PowerPoint. However I was given a super fast simulation computer locally so all I need is a VPN connection. Even if the VPN connection goes down, FloTherm will not cut off the simulation and it runs through the solve.

Every now and then I support local customers with their heat sink selection requests. Some local customers have asked for training sessions as well, which is something I would like to start fairly soon.

To learn more about Advanced Thermal Solutions, Inc., visit www.qats.com or contact ATS at 781.769.2800 or ats-hq@qats.com.

Dr. Reza Azizian Giving Nanofluid Presentation for PSMA Webinar

Reza Azizian

Dr. Reza Azizian, a research scientist at ATS and an expert on nanofluids, will speak about nanofluid technology as part of a PSMA webinar on Thursday, Oct. 6. (Josh Perry/Advanced Thermal Solutions, Inc.)


On Thursday, Oct. 6, Dr. Reza Azizian, a research scientist at Advanced Thermal Solutions, Inc. (ATS), a leading-edge engineering and manufacturing company focused on the thermal management of electronics, and an expert on nanofluid technology, nano-engineered surfaces, fluid dynamics, heat transfer and two-phase flow, will present “Nanofluids for Electric Cooling” as part of a webinar sponsored by the Power Sources Manufacturers Association (PSMA).

Dr. Azizian will join a panel of experts to discuss the enhanced heat transfer properties of nanofluids and their potential for the thermal management of compact, liquid-cooled electronics. Dr. Azizian will present an overview of the current stage of nanofluids technology, state-of-the-art research into nanofluid thermos-physical properties, convective heat transfer, and boiling heat transfer.

Prior to the webinar, Dr. Azizian sat down with the Josh Perry, Marketing Communications Specialist at ATS, to speak about his career, his interest in nanofluids technology, and the upcoming webinar.

JP: Thank you for sitting down with us. We want to highlight the work that the engineers are doing here at ATS, so I appreciate you taking a few minutes out of your schedule for this Q&A. I saw on your bio that you got your doctorate in Australia, is that where you’re from?
RA: Thanks for having me! No, originally I am from Iran and I did my undergraduate there; then I moved to Turkey and did my Master’s in Turkey. After that I moved to Australia and I did my Ph.D. in Australia. And then I ended up in Boston and did my post-doc at MIT.

JP: How did you end up at MIT?
RA: There is a very famous professor at MIT who was working on heat transfer in nanofluids back then. I invited him to Australia. He came and visited our facility in Australia and gave a talk and then he became interested in my research. Then he invited me over and during my Ph.D. I came to MIT as a visiting student and I was here for a year and then I went back to finish my Ph.D. and came back as a post-doc.

JP: How did you end up joining the team at ATS?
RA: It was four years ago as a visiting student. I have a very good friend in Australia and I was always interested in high technology, heat transfer, electronic cooling, and then he sent me the link to the ATS website and said, ‘Hey Reza, while you’re in Boston, you might want to visit this company.’ I thought, wow this is cool. I went through the website to see what ATS does and saw some fascinating projects done by ATS. So, I emailed Dr. Kaveh Azar and he responded to one of my emails and then that’s how we got in touch and then I visited the ATS facility, and coincidentally when I went back to MIT and I was talking to my supervisor and I said, ‘Oh, I went and visited this company and they’re doing a great job.’ He said, ‘Oh, the name is very familiar.’ We realized that when he graduated, something like 16 years ago, he applied here for a job and got a job offer but he got a position at MIT so now he’s a professor there. I kept my contact with Kaveh and then I went back to Australia and finished my Ph.D. After I came back to the U.S. as a post-doc, I invited them to MIT to come and visit our laboratory. So, we stayed in touch.

That’s how I came to know ATS and I realized that they are doing a great job in electric cooling and I was always interested because in electronic cooling there is no limit basically. Electronic equipment is becoming smaller and smaller every day and the only limit is thermal, at least at the moment. The only barrier is thermal issue for the advancement of electronic cooling and that’s why basically all of the funding from the Department of Defense, NASA, etc., it’s all on cooling. Because again, at this stage with all of these nanotechnologies and manufacturing capabilities, they don’t have any barrier to make things smaller except thermal. It’s a very interesting area of research and, you know, when you’re at the university you do cutting-edge research, which is cool, but it’s always nicer to do the research and then build something and use your knowledge in a more applicable way.

JP: Many of the people who read this will probably know, but what are nanofluids?
RA: Nanofluid is the term that you use when you disperse metal or metal oxide nanoparticles, which with the dimensions of 109 m, which is like .000000001 meter…very tiny, and you disperse these in your base fluid, whatever it is – could be water, oil, anything – and because they are tiny they are going to stay dispersed and at the same time because they are metal or metal oxide their thermal conductivity is going to be much higher than your base fluid. In simple language, thermal conductivity means the ability of the material to transfer heat. So, for example, for water the thermal conductivity is .6 W/mK, but for copper it’s like 400 W/mK, so you can assume that by mixing these two, again because the particles are tiny you will still have your liquid, which can easily flow, but at the same time it has higher thermal conductivity compared to the base fluid that you have.

The nanofluid term comes into play because of the heat transfer limitations that you normally have. In very general terms, there are two ways that you can increase the rate of heat transfer. One of them is increasing the surface area and the other is to increase the flow rate. Increasing the surface area, you are normally limited by the space that you have, right, and also increasing the flow rate you should use a bigger pump for example, to have a higher flow rate, which these are all costly. The only option left is if you can play with your working fluid and see how you can improve that and one of the ways you can improve that is by dispersing these nanoparticles to increase the overall thermal conductivity of your working fluid.

JP: How did you get interested in nanofluids? How did that become the focus of your studies and work?
RA: I’ve been working on nanofluids for the past 10 years. I came to know nanofluids during my Master’s and it was for my final-year project. I was looking for something cool and, even back then, nanotechnology was everywhere and then I was looking for something in the area of nanotechnology and heat transfer. I remember, my supervisor didn’t know much and he was like, ‘If you’re going to do this then you’re going to be on your own. I can’t help you much.’ It was funny, I went to the Internet to look up nanofluids and the first thing that came up was the name of this professor at MIT that I was working with during my post-doc. Back then, I remember I was sitting in my office and his name came up and I was telling my office mate, ‘This guy is cool. I’m going to go and work with him one day.’ And he laughed at me like, ‘Oh from here you’re going to go and work with him at MIT? Such a dream.’ And I’m here now.

JP: Obviously there is quite a bit more known about them now, how much has the subject matter changed in the 10 years that you’ve been studying nanofluids?
RA: The good thing is that now there are companies that are actually making nanofluids with very good stability – the particles don’t settle, they stay stable for a long time – and they commercialized a couple of nanofluids that are available now. They even use them in car engines, in the radiators, to increase the rate of cooling. They use it for CPU cooling. Next month, I’m going to go to Europe, there’s an event for the European Union, and they’re trying to basically commercialize nanofluids by 2020. They’re trying to see what are the barriers. The field’s improved a lot. The whole term of nanofluid was invented in 1999, so it’s only 17-18 years. So, it’s a fairly new area of research and seeing this technology commercialized now…the progress was quite fast.

JP: What will you be talking about in the PSMA webinar taking place on Thursday, Oct. 6?
RA: I’m going to be talking about nanofluids in general. What are nanofluids, basically, and what are the applications of nanofluids, in particular, in electronic cooling and high-powered electronics, which is the interest to PSMA. Then I’m going to give a brief explanation about the thermo-physical properties of the nanofluids followed by how they behave under laminar and turbulent flow conditions or even boiling for immersed cooling of electronics. And then I will conclude my talk by [explaining] what is the state-of-the-art and what are the future directions we expect nanofluids are heading to.

JP: Why do you think this is an important topic? Why do you think nanofluids are important as we go forward in the world of electronics cooling?
RA: These tiny particles, you add them to your working fluid and you don’t add much to the pumping power that you’re going to use because they are tiny, but at the same time you see 15-20 percent enhancement (depending on the nanoparticles and working fluid combination) in the heat transfer coefficient without changing any hardware. So, it has a very good potential and, again, this is only for single-phase heat transfer. In the case of immerse cooling of high-powered electronics, which boiling is the main heat transfer mechanism, we were able to see 200-250 percent enhancement in the value of critical heat flux by just changing the working fluid to nanofluid. It’s a very convenient way of doing it.

JP: Do you see nanofluids as the future of the industry? Do you see this is where electronics cooling is heading?
RA: I have to highlight that there are still problems with using nanofluids. This is why there is still research going on in this area. Stability is a big issue. You can use definitely some form of surfactant, which is a polymer that covers these particles’ surfaces and that keeps them dispersed. But in general if you don’t have that these particles, because they are tiny, they are under constant Brownian motion and when they become close to each other they stick to each other and then they agglomerate and they settle. So, there are still some issues that different research groups are trying to address but definitely it’s an area that I think is very useful for electronic cooling.

JP: Is research still going on here at ATS? Are you still really involved in the research and trying to find more applications for it?
RA: Yeah, yeah…we are always trying to push more towards using nanofluids. And hopefully we’ll see more in the future.

If you are interested in the PSMA webinar on Oct. 6, contact power@psma.com no later than Oct. 4. For more information about Advanced Thermal Solutions, Inc., its thermal management products, testing equipment, and consulting services, visit www.qats.com.