Abstract: The performance of steam ejector does have effects on the heat utilization rate of the seawater desalination system in power plants. The traditional ejector design adopts Sokolov design method, which uses too much experience coefficients and is inaccurate in mixed steam pressure calculation. Therefore, the designed performance of the ejector is low. In consideration of the shortages of this method, the design of the ejector mixing section is divided into two parts and the calculations of the mixing section area ratio and the throat shock are induced to revise the ejection coefficient calculation formula and variation operation curve equation. In order to verify the reliability of this modified method, an ejector model with the scale of 1∶20 is built and tested. In the test, the ejection coefficient, the variable injection pressure and the variable backpressure operation curve are measured and analyzed. The test results show that the operation performance of the ejector model designed with the new method is greatly improved and is consistent with the calculated results

Key words: seawater desalination, ejector, area ratio of mixing section, throat shock calculation, optimization design, model test