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Spray cooling in a closed system with different fractions of non-condensables in the environment.

Author(s) : JIANG S., DHIR V. K.

Type of article: Article

Summary

Spraying liquid on a hot surface is an effective method for dissipating high heat fluxes from integrated circuit chips. In this study, HAGO nozzle was used to create the spray and a closed system with water as a test liquid was used. The effect of presence of non-condensables in the closed system on the heat transfer coefficient in both single phase and boiling modes were investigated. Maintaining an air partial pressure of 3.1 kPa, while varying the vapour partial pressure from 7.3 to 97.9 kPa, the total system pressure was varied from 10.4 to 101 kPa. Experiments were also conducted by keeping the system pressure constant at 101 kPa and varying the air partial pressure inside the chamber from 2.75 to 93.7 kPa. In each case, liquid temperature corresponded to the saturation temperature corresponding to partial pressure of vapour and this was also approximately the ambient temperature of vapour and air mixture in the chamber. It was found that in the single phase regime, overall heat transfer coefficient for lower concentration of non-condensables in the system is much higher than that for the case with more non-condensables. In boiling, heat transfer coefficient depends on the total system pressure in the system. For the same system pressure, data for different partial pressures of air overlap. For a water mass flux of 17.5 ml/min.cm2 at room temperature, critical heat flux as high as 230 W/cm2 was obtained at a surface temperature of 127 °C.

Details

  • Original title: Spray cooling in a closed system with different fractions of non-condensables in the environment.
  • Record ID : 2005-1493
  • Languages: English
  • Source: International Journal of Heat and Mass Transfer - vol. 47 - n. 25
  • Publication date: 2004/12

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