Category Archives: Liquid Cooling

Yesterday we let everyone know about “Understanding Boiling Heat Transfer: a “how to” article from ATS Thermal Labs“.  Hopefully you had a chance to look at our “how to” article as a basic understanding of this important concept.  And there’s relatively new research in this space that’s worth a look as well.

As reported in Purdue University News,  out at Purdue University’s labs, Indiana’s 21st Century Research and Technology Fund has provided $1.9 million to Purdue and Delphi Corp. in Kokomo, Ind., to help commercialize an advanced cooling system using boiling die-electric liquid in microchannels to cool electronic components in hybrid and electric cars.

Tannaz Harirchian, a doctoral student on the project noted that:

One big question has always been, where is the transition from macroscale boiling to microscale boiling?  How do you define a microchannel versus a macrochannel, and at what point do we need to apply different models to design systems? Now we have an answer.

Here is an abstract of the work being done:

ABSTRACT

Boiling Heat Transfer and Flow Regimes in Microchannels – a Comprehensive Understanding

Suresh V. Garimella and Tannaz Harirchian

Cooling Technologies Research Center
School of Mechanical Engineering and Birck Nanotechnology Center, Purdue University

Although flow boiling in microscale passages has received much attention over the last decade, the implementation of microchannel heat sinks operating in the two-phase regime in practical applications has lagged due to the complexity of boiling phenomena at the microscale. This has led to difficulties in predicting the heat transfer rates that can be achieved as a function of the governing parameters. From extensive experimental work and analysis conducted in recent years in the authors’ group, a clear picture has emerged that promises to enable prediction of flow boiling heat transfer over a wide parameter space. Experiments have been conducted to determine the effects of important geometric parameters such as channel width, depth, and cross-sectional area, operating conditions such as mass flux, heat flux and vapor quality, as well as fluid properties, on flow regimes, pressure drops and heat transfer coefficients in microchannels. High-speed flow visualizations have led to a detailed mapping of flow regimes occurring under different conditions. In addition, quantitative criteria for the transition between macro- and micro-scale boiling behavior have been identified. These recent advances towards a comprehensive understanding of flow boiling in microchannels are summarized here.

There’s more on the boil at Purdue University and the applications for the research are far-reaching beyond cooling just automotive electronics.  Click to “New findings could help hybrid, electric cars keep their cool” so you can have a read of the Purdue University News Article with links to the research.