向心压气机进出气道设计及整机模拟

向心压气机的通流部件主要包括:进气道、动叶栅、静叶栅、出气道,本文对除静叶栅、动叶栅之外的静止通流部件的子午面进行设计,进气道、出气道子午面设计采用等截面法,能保证进出气均匀、轴向对称;并对所设计的向心压气机进行了整机模拟及变工况分析。结果表明,所设计的向心式压气机气动性能符合要求,向心式压气机是可行的。

向心式压气机的数值模拟及优化

根据某一压气机级的设计要求,采用向心式结构,合理地设计向心式压气机的气动参数和叶型参数,然后采用ANSYS-geometry对叶片型线进行参数化设置,最后在Workbench平台上对此向心式压气机进行数值模拟和优化。根据数值模拟结果,分析其内部流场流动结构,找到向心式压气机的较优工况;再研究优化后该向心式压气机的总压比、效率随相对流量和转速变化的特性曲线,分析向心式压气机的变工况特性。

SCO_2向心式压气机的数值模拟与分析

本文根据超临界二氧化碳布雷顿循环对压气机的要求,设计向心式压气机。采用中弧线叠加厚度的方法进行叶型设计,并基于NIST物性数据库建立真实二氧化碳数据模型。在Workbench平台上进行叶型设计、网格划分、流场计算和结果后处理,并对超临界二氧化碳向心式压气机进行级变工况分析。结果表明:超临界二氧化向心式压气机在设计点滞止等熵效率可以到达91.2%,总压比可以达到1.29,增压主要在动叶中完成,静叶中改变气流方向;当转速小于设计转速时,压气机正常工作的流量范围变大,效率较高但是压比小于1.2;当转速大于设计转速时,向心式压气机的正常工作的流量范围逐渐变小,效率小于设计点,但是压比大于1.3。

Radial Forces in a Centrifugal Compressor; Experimental Investigation by Using Magnetic Bearings and Static Pressure Distribution

The volute of a centrifugal compressor causes a non-uniform pressure distribution which leads to a radial force on the impeller. This force was measured using magnetic bearings. In addition, the radial force was estimated using the static pressure distribution measured at the impeller outlet. The impeller force was found to be the highest at choke, the lowest at the design flow and moderate at stall. The radial force determined from the pressure measurements was only slightly different from the force obtained from the bearing measurements. The rotational speed was seen to affect the force to some extent.