旋转盘腔轴向通流的压降和温升数值研究

Numerical Study on Pressure Drop and Temperature Rise of an Axial Throughflow Passing Through Rotating Cavity

关键词:  轴向通流  旋转盘腔  压降  温升  数值模拟

Key words:  Axial throughflow  Rotating cavity  Pressure drop  Temperature rise  Numerical simulation

摘要:

为获得旋转雷诺数对盘腔轴向通流温升和压降的影响，对轴向通流雷诺数Re_x恒定为1.0×10⁵，旋转雷诺数Re_ω=0~5.31×10⁶、绝热边界下的流动进行了数值模拟，从流场特征、盘面绝热温升以及轴向通流压降和温升等三个方面进行了分析。研究表明，旋转雷诺数对于盘腔内部和轴向通流的流动均具有显著影响；尽管是绝热盘面，但是由于高速旋转的黏性耗散作用引发盘腔内气流的温升，由温度差引起的浮升力对于盘腔内流动和盘面温度分布的影响也是不可忽略的；随旋转雷诺数增大，轴向通流出口温度相对进口温度的温升急剧增大，在旋转雷诺数<2.5×10⁶时，轴向通流相对温升系数在0.01以内，当旋转雷诺数>4.5×10⁶时，轴向通流相对温升系数达到0.04以上。

Abstract:

To demonstrate the effects of rotational Reynolds number （Re_ω） on the pressure drop and temperature rise of an axial throughflow passing through rotating cavity， a series of numerical simulations were performed under a fixed axial throughflow Reynolds number Re_x=1.0×10⁵， rotational Reynolds number between 0 and 5.31×10⁶ in adiabatic thermal boundary condition. The detailed flow fields， the adiabatic temperature rise on rotating disks， as well as the pressure drop and temperature rise of an axial throughflow were analyzed. The results show that the rotational Reynolds number affects the flow fields significantly， both inside the rotating cavity and inside the axial throughflow path. Although the disk is thermally adiabatic， the centrifugal-buoyancy force caused by temperature rise is not to be ignored due to the viscous dissipation effect， which affects the flow instable and temperature distribution. As the rotational Reynolds number increases， the absolute temperature rise with respect to the axial throughflow inlet increased rapidly. When the rotational Reynolds number is less than 2.5×10⁶， the relevant temperature-rise coefficient of axial throughflow is generally less than 0.01. When the rotational Reynolds number is greater than 4.5×10⁶， the relevant temperature-rise coefficient of axial throughflow reaches up to 0.04.