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Visualization of Electrohydrodynamic Effects and Time Scale Analysis for Impinging Spray Droplets of HFE-7000
| Content Provider | Semantic Scholar |
|---|---|
| Author | Kreitzer, Paul J. Kuhlman, John M. |
| Copyright Year | 2008 |
| Abstract | Spray cooling is becoming a leading technique for removing excess heat from high heat flux electronics. Electrohydrodynamic effects have been found to result in significant variation in spray behavior once the applied voltage level is increased enough to reach the Rayleigh limit. In the present work the dielectric coolant HFE-7000 has been used to study spray cooling heat transfer across a thick film resistor heater mounted to a 16 mm diameter pedestal. Heater power levels have been varied from 0 to 80 Watts, with spray flow rates varied from 2 GPH to 6 GPH (2.1x10 m/s to 6.3x10 m/s). Applied voltage levels between 0 kV and 30 kV with both positive and negative polarity have been applied directly to the brass spray nozzle, resulting in contact charging of the spray. A high-speed video camera was used to study behavior of both the impinging spray and the liquid film that formed on the heater surface. Time scale estimates of the various physical processes within the spray and the liquid film have indicated the time between droplet impacts falling into a crater from a previous droplet to be the shortest time scale, which thus will limit the amount of heat transfer that may take place during spray cooling. However, the observed time between large droplet impacts onto the same heater surface location is comparable to the computed time to heat and vaporize a large drop, indicating a new explanation for the onset of spray cooling CHF: localized dryout of the original large droplet impact craters. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://web.statler.wvu.edu/~spraycool/Publications/10.pdf |
| Alternate Webpage(s) | http://www2.statler.wvu.edu/~spraycool/Publications/10.pdf |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Accidental Falls Computer cooling Cool - action Cryptographic hash function Diameter (qualifier value) Eighty Estimated Heart failure Heat sink Heater Device Component Logic level Meter per Second Nozzle Device Component Occur (action) Offset binary Onset (audio) Physical Phenomenon or Property Rayleigh–Ritz method Resistor Device Component Short Wafer (electronics) Watt polarity voltage |
| Content Type | Text |
| Resource Type | Article |
