摘要
将向心透平(以下简称透平)作为研究对象,选取R123作为循环工质。采用热力计算方法,对动叶入口工质速度气流角α_1、动叶出口工质实际相对速度的方向角β_2对透平性能指标(轮周效率)的影响进行计算分析,确定α_1、β_2的最优值。α_1的取值范围为15°～25°,变化步长设定为1°。β-2的取值范围为25°～45°,变化步长设定为2°。在设计参数优化的基础上,采用CFX16. 0软件对透平蜗壳内部速度场、静压分布进行数值模拟。当β_2为25°时,轮周效率、动叶转速均随α1的增大而减小,α_1宜选取15°。当α_1为15°时,轮周效率随β_2的增大先增大后减小,在β_2为34°时轮周效率出现最大值,β_2宜选取34°。动叶转速随β_2的增大持续增大,存在最佳转速(4 354min^(-1))对应轮周效率最大值。蜗壳内的速度场分布非常复杂,径向及周向的速度分布均不均匀。喷嘴出口气体速度很高,一直延伸到蜗壳内部。沿流道流向蜗壳的出口,流体速度逐渐降低,在蜗壳出口形成气体旋涡。蜗壳内静压分布不均,蜗壳的进口处存在呈周向分布的局部高压区,蜗壳出口的静压比较低。
Taking the centripetal turbine(hereinafter referred to as turbine)as the study object,R123 is selected as a circulating working fluid.The influence of the velocity airflow angle α1 of the rotor blade inlet working fluid and the relative velocity direction angle β2 of the rotor blade outlet working fluid on the turbine performance index(wheel circumference efficiency)is calculated and analyzed by the thermal calculation method to determine the optimal values ofα1 and β2.The value ofα1 is from 15°to 25°,and the change step size is set to 1°.The value of β2 is from 26°to 44°,and the change step size is set to 2°.Based on the optimization of design parameters,the numerical simulation of the velocity field and static pressure distribution inside the turbine volute is performed by CFX 16.0 software.When β2 is 25°,the wheel circumference efficiency and the speed of the rotor blade decrease with the increase of α1,and α1 should be chosen as 15°.Whenα1 is 15°,the wheel circumference efficiency first increases and then decreases with the increase of β2,the maximum value of wheel circumference efficiency appears when β2 is 34°,and β2 should be chosen as 34°.The speed of the rotor blade increases continuously with the increase of β2,there is an optimal speed(4354 min^-1)corresponding to the maximum value of wheel circumference efficiency.The velocity field distribution inside the volute is very complex,radial and circumferential velocity distribution is uneven.The nozzle outlet gas velocity is very high and extends to the inside of the volute.Along the flow path to the outlet of the volute,the velocity of the fluid gradually decreases,and the gas vortex is formed at the volute outlet.The static pressure distribution inside the volute is uneven,there is a circumferentially distributed local high pressure zone at the inlet of the volute,and the static pressure at the volute outlet is relatively low.
作者
李新禹
郝旭涛
陈林
孟林
LI Xinyu;HAO Xutao;CHEN Lin;MENG Lin
出处
《煤气与热力》
2019年第1期12-15,共4页
Gas & Heat
基金
天津市自然科学基金(C16JCZDJC31400)
关键词
向心透平
轮周效率
参数优化
数值模拟
centripetal turbine
wheel circumference efficiency
parameter optimization
numerical simulation
