Category Archives: Instrument

The New iFLOW-200 Tests and Measures the Thermal and Hydraulic Performance of Cold Plates

Advanced Thermal Solutions, Inc. (ATS) has released a new thermal test instrument, the iFLOW-200, which assesses the thermal and hydraulic characteristics of cold plates in electronics cooling. It can be used to simulate a wide range of conditions to optimize a cold plate’s performance before it is commercialized or prior to its use in an actual application.


The iFLOW-200 measures coolant temperatures from 0-70°C with the high accuracy of ± 1°C. Differential pressure of the coolant in the cold plate is measured up to 103,000 Pa (15 psi), with the precise accuracy of ± 1%. Distilled water is used as the reference coolant. For test comparisons, the systems coolingVIEW software can also calculate thermal resistance and pressure drop as a function of flow rate for selected liquids.


The instrument system includes a pair of K-type thermocouples for measuring temperature changes on the cold plate surface. Temperatures are monitored on the coolingVIEW interface.


The iFLOW-200 system features easy set up and operation to save time when evaluating different cold plate models. Designed for accuracy and convenience, the iFLOW-200 simply requires setting the starting and ending coolant flow rates, and choosing the dwell time, pumping power and other parameters. These are easily done on any PC using the systemd user-friendly application program.

The iFLOW-200 system features separate controller and hydraulics enclosures with USB connections. The hydraulic package includes a fluid level indicator, coolant inlets and outlets from/to the cold plate under test, ports for surface temperature thermocouples, and a fluid cooling system for its internal heat exchanger. The iFLOW-200 is also ideal for testing alternative liquids.


More information about the iFLOW-200 Cold Plate Characterization System can be found at

Some Basic Principles of Wind Tunnel Design

Wind tunnels generate uniform air flows, with low turbulence intensity, for thermal and hydraulic testing. These devices have been around for more than a century, and are used in many industries, including aerospace, automotive, and defense. They also play a key role in electronics thermal management. Wind tunnels are made in different shapes and sizes, from just 30 cm long to large enough to contain a passenger airplane. But the basic idea behind all wind tunnels is universal.

There are two basic kinds of wind tunnels. One is the open type, which draws its air from the ambient and exits it back to the ambient. This kind of wind tunnel provides no temperature controls. The air follows the ambient temperature. The second type of wind tunnel is the closed loop wind tunnel, whose internal air circulates in a loop, separating it from outside ambient air. The temperature in a closed loop wind tunnel can be controlled using a combination of heaters and heat exchangers. Air temperatures can be varied from sub-ambient to over 100oC. Figure 1 shows a schematic of a closed loop wind tunnel.

In general, closed loop wind tunnels are made with the following sections:

1-Test section

2-Settling chamber

3-Contraction area


5-ÂBlower assembly

6-Heater/heat exchanger assembly

Figure 1. Schematic of an ATS Closed Loop Wind Tunnel.

A good quality wind tunnel will have a flow uniformity of 0.5-2% and turbulence intensity of 0.5-2%. It should provide temperature uniformity within 0.1-0.5oC at the inlet of the test section [1].

108K different push pin heat sink assembly configurations featuring 3 different pitch heat sink types, 3 different fin geometries, brass and plastic push pins


To achieve uniform, high quality flow in the test section, the settling chamber and the contraction area are used to smooth the flow. The role of the settling chamber, which is upstream of the contraction area, is to eliminate swirl and unsteadiness from the flow. The settling chamber includes a special honeycomb and a series of screens. As long as a flows yaw angles are not greater than about 10o, a honeycomb is the most efficient device for removing swirl and lateral velocity variations and to make the flow more parallel to the axial axis [2]. Large yaw angles will cause honeycomb cells to stall, which increases the pressure drop and causes non-uniformity in the flow. For large swirl angles, screen meshes should be placed before the honeycomb. For swirl angles of 40o, a screen with a loss factor of 1.45 will reduce yaw and swirl angles by a factor of 0.7. Several screens are needed upstream of the honeycomb to bring the swirl down to 10o.

Using a honeycomb will also suppress the lateral components of turbulence. Complete turbulence annihilation can be achieved in a length of 5-10 cell diameters [2]. Honeycombs are also known to remove the small scale turbulence caused by the instability of the shear layer in front of them. This instability is proportional to the shear layer thickness, which implies a short honeycomb has a better ratio of suppressed turbulence to that generated.

Screens break up large eddies into smaller ones which decay faster. They lower turbulence drastically when several screens are placed in a row. Screens also make flow more uniform by imposing a static pressure drop which is proportional to velocity squared. A screen with a pressure drop coefficient of 2 removes nearly all variations of longitudinal mean velocity. Low open area screens usually create instabilities. In general, screens should have openings larger than 57%, with wire diameters about 0.14 to 0.19 mm. Sufficient distance is needed between multiple screens to stabilize static pressure from perturbation. This distance is typically a percentage of the settling chamber diameter.

The contraction area is perhaps the most important part of a wind tunnel’s design. Its main purpose is to make the flow more uniform. It also increases the flow at the test section, which allows flow conditioning devices to be at lower flow section with less pressure drop. Batchelor used the rapid distortion theory and estimated the variation in mean velocity and turbulence intensity [3]

A considerable number of shapes have been investigated for contraction, including 2-D, 3-D and axisymmetric shapes with various side profiles.

The shape of the contraction can be found using potential flow analysis. Consider the axisymmetric contraction shown in Figure 2 [4]

Figure 2. Schematic of an Axisymmetric Contraction [4].

The design of a wind tunnel is a lengthy process and, as shown above, it requires extensive knowledge and experience in both theory and construction. A novice might attempt to construct a tunnel, but considering the time spent, it might not be justified economically. Wind tunnel design also depends on economic and space constraints. Larger wind tunnels allow more space to have all the conditioning elements in place. A space-constrained wind tunnel must compromise some features at the cost of reduced flow quality, but can still be acceptable for practical engineering purposes.


  1. Azar, K., Thermal Measurements in Electronics Cooling, Electronics Cooling Magazine, May 2003.
  2. Bell, J. and Mehta, R., Design and Calibration of the Mixing Layer and Wind Tunnel, Stanford University, Department of Aeronautics and Astronautics, May 1989.
  3. Batchelor, G., The Theory of Homogeneous Turbulence, Cambridge University Press, 1953.
  4. Edson, D. and Joao, B., Design and Construction of Small Axisymmetric Contractions, Faculdade de Engenharia de Ilha Solteira, Brazil, 1999.

An Instrument for Measuring Air Velocity, Pressure and Temperature in Electronics Enclosures

For engineer-level thermal management studies, the iQ-200 instrument from Advanced Thermal Solutions, Inc, ATS, can simultaneously measure air velocity, air pressure and the temperature of components and surrounding air at multiple locations inside electronic systems. This enables users to obtain full and accurate profiles of components, heat sinks, PCBs and other electronics hardware to enable more effective thermal management.

Developed by Advanced Thermal Solutions, Inc., ATS, the iQ-200 system simultaneously captures data from up to 12 J-type thermocouples, 16 air/velocity sensors, and four pressure sensors.

The thermocouples provide surface area temperature measurements on heat spreaders, component packages, housing hardware, and elsewhere to track heat flow or detect hot spots. Temperature data is tracked from -40 to 750°C. The sensors (available separately) measure both air temperature and velocity at multiple points allowing a detailed analysis of airflow.

Candlestick Sensor from ATS

Thin, low profile ATS candlestick sensors can be easily positioned throughout a system under test and measure airflow from -10 to +6°C. Air velocity is measured from natural convection up to 6 m/s (1200 ft/min). The iQ-200 can be factory modified to measure airflow to 50 m/s (10,000 ft/min) and air temperature up to 85°C. Four differential transducers capture pressure drop data along circuit cards, assemblies and orifice plates. Standard pressure measurement capabilities range from 0- 1,034 Pa (0 – 0.15 psi).

The ATS iQ-200 system comes preloaded with user-friendly iSTAGE application software which effectively manages incoming data from the various sensor devices, and allows rich graphic presentation on monitors and captured on videos or documents. The iQ-200 connects via USB to any conventional PC for convenient data management, storage and sharing.

More information on the iQ-200 system from ATS can be found on (, or by calling 781-769-2800.

ATS welcomes Test Equipment Connection to our Distributor Partner Ranks

We’ve got a new distribution partner, Test Equipment Connection! Test Equipment Connection is located in Florida, but sells worldwide to a variety of markets. They sell both new and refurbished test equipment. So if you need something, and your budget is stretched, these are the guys to call!

We had a chance to have a quick phone conversation with their Manager of Business Development, Phil Vogel last week. Test Equipment Connection has been around since 1993. They both buy and sell test equipment and provide full support. He noted that thermal analysis and measurement is a growing need in the technology sector and we couldn’t agree more! Our latest one day short course on thermal management was sold out!

So, if you need test equipment, such as spectrum analyzers or RF or microwave test equipment or ATS thermal test instruments, visit their web site at and contact them!

You can read more about it at our press release page.

ATS Releases Our Latest Instrument: The iQ-200 which measures Air Temperature, Velocity, and Pressure with a Single Instrument

We spend a lot of time coming up with new ways to solve thermal management problems for our customers. In fact, our case study list reads like a rogues gallery of thermal problems: from obstructed air flow to over heat sink application, we’ve seen almost everything in the thermal engineering. But what do we use to hunt down the root cause of these problems? Well, in part we  use excellent thermal analysis instruments.

One such new instrument is the iQ-200. This may be among the few, (if not only) thermal management instrument that allows you to simultaneously or individually test air temperature, air velocity, and pressure drop in one instrument.

Key features include:

  • Sixteen hot wire anemometer ports measure velocity using ATS single-sensor technology, requiring no need to change sensors when measuring different velocity ranges.
  • twelve thermocouple ports supporting J, K, T and E types, with a range of -40 to 750C.
  • Pressure is measured by four ports, supporting differential or absolute pressure, with a range of 0-1,035Pa (0-0.15 psi)
  • User-friendly LabVIEWTM- based IQstage data acquisition software is included in the system. IQstage manages incoming data from various sensors and provides a rich graphical presentation of the results. It automates your test process so you can do more valuable work.

This instrument lets you replace multiple others in your lab, saving you cost and space. To learn more about points on how a student competes in essay writing.

You can read more by clicking to over to The iQ-200 Air Temperature, Velocity and Measurement Instrument, email us to ask for more information by clicking, or call our lab at 781-769-2800