THE EXPERIMENTAL STUDY OF EJECTOR WITH PETAL NOZZLE
| Autor: | Yang, Sheng-Chu, 楊勝竹 |
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| Rok vydání: | 1998 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 86 Experimental study was conducted to investigate the performance of ejector with petal nozzle applied in steam-jet refrigeration system. Four ejectors with different area ratio values (AR) and mixing section length were tested in the present study. The performance of ejector with petal nozzle increases with increasing AR, but it achieves an optimum value at about AR=220. The performance then decreases when AR is larger than 220. By contrast, the performance of ejector with conical nozzle decreases monotonously with increasing AR. At AR=196, the performance of ejector with petal nozzle does not vary in this three mixing length. But at AR=300, the performance decreases with decreasing mixing length. This indicates the mixing length has its optimum value meeting each AR. Compared with the ejector with conical nozzle, the compression ratio can be enhanced about 10%~25% if the petal nozzle was adopted. In other word, if the compression ratio is a constant, the larger entrainment ratio can be achieved by using petal nozzle. From the analysis with one-dimensional compressible flow theory, the isentropic efficiency of mixing can be promoted about 5%~10% by the use of petal nozzle. Combine experiment and theory, we develop the half-experience equation that predicts the isentropic efficiency of mixing of the ejector. If we can add the correction of isentropic efficiency of mixing to the analysis with one-dimensional theory, it will make the prediction more accurate. In addition, from the analysis of two-stage ejector, the maximum COP=0.33 can be achieved if the second stage ejector was replaced by ejector with petal nozzle. This indicates the petal nozzle has potential if it is applied in the multi-stage ejectors. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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