为了提高航空发动机离心喷嘴的雾化性能,优化喷嘴喷口结构参数,基于两相界面追踪流体体积(Volume of fluid,VOF)方法对离心喷嘴进行了仿真分析,并通过实验验证了VOF方法的可靠性。采用正交试验方法完成以喷嘴出口直径、出口直管段长度...为了提高航空发动机离心喷嘴的雾化性能,优化喷嘴喷口结构参数,基于两相界面追踪流体体积(Volume of fluid,VOF)方法对离心喷嘴进行了仿真分析,并通过实验验证了VOF方法的可靠性。采用正交试验方法完成以喷嘴出口直径、出口直管段长度、扩张角、扩张段长度为优化参数,以雾化锥角、液膜厚度和流量系数作为雾化性能指标的试验设计。通过极差方差分析讨论各个参数对雾化性能指标影响的显著性并利用回归分析得到规律曲线,获得最佳参数组合。结果表明:4个结构参数中扩张角是对喷嘴雾化性能影响最大的因素;扩张角和喷口直径的增大可以明显地增大雾化锥角,减小液膜厚度和流量系数;扩张段长度的增大会使雾化锥角减小,同时减小液膜厚度和流量系数;直管段长度的变化对各指标的影响不大;当扩张角θ为60°,出口直径D为0.6mm,出口直管段长度L1为0.3mm,扩张段长度L2为0.4mm时,雾化性能最佳。展开更多
The cavitation is very common in a centrifugal pump,especially when the speed is very high,and it seriously influences the centrifugal pump performance.In this investigation,the RNG k-ε turbulence model and the cavit...The cavitation is very common in a centrifugal pump,especially when the speed is very high,and it seriously influences the centrifugal pump performance.In this investigation,the RNG k-ε turbulence model and the cavitation model with consideration of the mass transferring are first used to simulate the cavitation performance of the high-speed centrifugal pump without taking any measure for improving the pump cavitation performance.The calculation results reveal that a number of bubbles appear in the centrifugal pump flow channel,and the head as well as the flow rate of the high-speed centrifugal pump are far from its design condition.The cavitation performance can be improved effectively by arranging a variable pitch inducer and adopting an annular nozzle scheme.The flow field analysis of the pump is conducted to obtain the suitable working temperature distribution at different void fractions.On one hand,with the same void fraction,the head of the centrifugal pump drops slowly with the increase of temperature.However,when the temperature exceeds 90°C,the head of the pump drops rapidly.On the other hand,at the constant temperature,the higher the void fraction,the worse the cavitation performance.This research conducted under different temperatures and void fractions provides some guidance for designing an effective high-speed centrifugal pump.展开更多
文摘为了提高航空发动机离心喷嘴的雾化性能,优化喷嘴喷口结构参数,基于两相界面追踪流体体积(Volume of fluid,VOF)方法对离心喷嘴进行了仿真分析,并通过实验验证了VOF方法的可靠性。采用正交试验方法完成以喷嘴出口直径、出口直管段长度、扩张角、扩张段长度为优化参数,以雾化锥角、液膜厚度和流量系数作为雾化性能指标的试验设计。通过极差方差分析讨论各个参数对雾化性能指标影响的显著性并利用回归分析得到规律曲线,获得最佳参数组合。结果表明:4个结构参数中扩张角是对喷嘴雾化性能影响最大的因素;扩张角和喷口直径的增大可以明显地增大雾化锥角,减小液膜厚度和流量系数;扩张段长度的增大会使雾化锥角减小,同时减小液膜厚度和流量系数;直管段长度的变化对各指标的影响不大;当扩张角θ为60°,出口直径D为0.6mm,出口直管段长度L1为0.3mm,扩张段长度L2为0.4mm时,雾化性能最佳。
基金the National Natural Science Foundation of China (Grant No.51279145).
文摘The cavitation is very common in a centrifugal pump,especially when the speed is very high,and it seriously influences the centrifugal pump performance.In this investigation,the RNG k-ε turbulence model and the cavitation model with consideration of the mass transferring are first used to simulate the cavitation performance of the high-speed centrifugal pump without taking any measure for improving the pump cavitation performance.The calculation results reveal that a number of bubbles appear in the centrifugal pump flow channel,and the head as well as the flow rate of the high-speed centrifugal pump are far from its design condition.The cavitation performance can be improved effectively by arranging a variable pitch inducer and adopting an annular nozzle scheme.The flow field analysis of the pump is conducted to obtain the suitable working temperature distribution at different void fractions.On one hand,with the same void fraction,the head of the centrifugal pump drops slowly with the increase of temperature.However,when the temperature exceeds 90°C,the head of the pump drops rapidly.On the other hand,at the constant temperature,the higher the void fraction,the worse the cavitation performance.This research conducted under different temperatures and void fractions provides some guidance for designing an effective high-speed centrifugal pump.
