Experimental investigation of evaporation heat transfer and pressure drop of ammonia in a 30¡ã chevron plate heat exchanger
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- 作者：Mohammad S. Khan ; Tariq S. Khan ; Ming-C. Chyu ; Zahid H. Ayub
- 关键词：Plate heat exchanger ; Ammonia ; Heat transfer ; Evaporation ; Pressure drop
- 刊名：International Journal of Refrigeration
- 出版年：2012
- 出版时间：September, 2012
- 年：2012
- 卷：35
- 期：6
- 页码：1757-1765
- 全文大小：722 K
文摘
Ammonia, an environment friendly natural refrigerant with attractive thermo-physical properties is a potential replacement of the synthetic refrigerants with high ozone depletion and global warming potentials. Experimental heat transfer and pressure drop data are obtained for two phase evaporation of ammonia in a commercial plate heat exchanger for symmetric 30¡ã/30¡ã chevron plates. The plate heat exchanger was configured in a single pass U-type counter flow arrangement with liquid ammonia evaporating in upward flow direction and glycol/water solution simulating the heat load in counter flow. Experiments were carried out for saturation temperatures ranging from ?25?¡ãC to ?2?¡ãC. The heat flux was varied between 21?kW?m?2 and 44?kW?m?2. Experimental results show significant effect of saturation temperature, heat and exit vapor quality on heat transfer coefficient and pressure drop. Two phase Nusselt number and friction factor correlations are proposed.