圆孔型预旋喷嘴转静盘腔内流动换热特性数值研究

Numerical Investigations on the Flow and Heat Transfer Characteristics of the Rotor Stator System with Circle Pre-swirl Nozzles

运用RANS(数值求解三维)方程和SST(紊流模型)的方法研究了圆孔形预旋喷嘴转静盘腔内流动换热特性。通过数值计算获得的实验测量预旋盘腔内的阻力系数和努赛尔数与实验数据吻合良好,验证了数值方法的有效性。分析了3种不同进气预旋比和湍流系数对圆孔型预旋喷嘴转静盘腔内的流动换热特性的影响。研究结果表明:旋流比、阻力系数和转盘表面换热随着湍流系数的增大而增大。阻力系数由于受旋转泵效应的影响沿径向逐渐增大,受进气影响在进出口附近周向不均匀较为明显。进气预旋比较小时转盘对气流做功提高气流总温,当进气预旋比达到1.5左右时,转盘无需推动气流转动,气流总温相对较低。进气流冲击导致进气位置转盘表面Nu周向分布不均匀,并导致形成转盘表面强换热区。

The flow and heat transfer characteristics of the rotor stator cavity with circle pre-swirl nozzle structures was numerically investigated using three-dimensional Reynolds-Averaged Navier-Stokes( RANS) and SST turbulence model.The numerical drag coefficient and Nu coefficient distributions in the rotor stator cavity agreed well with the experimental data. The reliability of the utilized numerical method was also demonstrated. Three different turbulent flow parameters and pre-swirl ratios were used to analyze the flow and heat transfer performance of the rotor stator system with circle pre-swirl nozzles. The obtained results show as the turbulent flow parameter increases,swirl ratio,static pressure coefficient and the heat transfer on the rotating disc increase,and vary apparently along the circumference because of the impingement of the pre-swirl flow. The drag coefficient is gradually increasing along the radial direction due to the influence of the rotary pump,and the non-uniformity along the circumferential direction at the inlet and outlet position is observed due to the inlet pre-swirl flow influence. The rotational disc does work on the flow and increases the total temperature at the low pre-swirl inlet flow condition. The total temperature of the fluid is relative low at the pre-swirl ratio 1. 5 because the rotational disc does not do work on the airflow or drive the flow rotation. The inlet flow impinges on the rotational disc and results in the non-uniformity distribution of the Nu along the circumferential direction. This flow behavior leads to the high heat transfer region on the rotational disc surface.