Optimal Performance Design For A Variable Throat Ejector

• Main Authors: Ting-Yau Shiu, 許庭耀
• Other Authors: 顏瑞和
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/29271964948933079244

碩士 === 國立臺灣大學 === 機械工程學研究所 === 98 === For solar-driven ejector refrigeration system, operating temperature may change with the variation in solar radiation and ambient temperature. Thus, a conventional fixed throat area ejector may not work at its optimal performance. In this study, a variable ejector has been designed, which incorporates a needle into the ejector. This allows the primary throat area to be changed by adjusting the position of the needle. By means of this controlled needle modification, an unsteady operating temperature can be taken into account. For a given throat area, an optimum generator temperature exists at which the critical condenser temperature is the same as the actual condenser temperature. A regressive equation, related to the corresponding optimum throat area ratio with respect to the operating conditions, is obtained. A3/At=0.71701Tg-0.0196Te+0.70234Tc+ 0.00204TgTe-0.01185TgTc-0.00257TeTc-43.9477. From the practical operating point of view, if the generator, evaporator or condenser temperature is measured out, the ejector can be adjusted to the corresponding optimal throat area ratio using the equation. The system then operates with optimal performance.