A Model of Mass and Heat Transfer for Disc Temperature Prediction in Open Compressor Cavities
A Model of Mass and Heat Transfer for Disc Temperature Prediction in Open Compressor Cavities
复制标题
用于预测开放式压缩机腔室中盘温度的传质和传热模型
DOI：
10.1115/1.4064082
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发表时间：
2024
期刊：
影响因子：
--
通讯作者：
Nicholas T
中科院分区：
文献类型：
--
作者：
Nicholas T
准确预测压气机空腔内的传热对设计高效可靠的航空发动机至关重要。热传递影响压缩机转子的热膨胀，进而影响压缩机叶片的叶尖间隙。本文提出了一种新的，基于物理的预测理论模型的传热和流动结构的开放式压缩机腔，它可以用来准确地计算盘温度。空腔的径向较高区域由热主流流和用于冷却涡轮机的轴向通流之间的温差产生的浮力效应主导。空腔中的空气与该通流之间的强烈相互作用在低半径处产生混合区域。对于给定的几何形状，热传递和流动物理由四个参数控制：旋转雷诺数Re、浮力参数βΔT、压缩性参数χ和Rossby数Ro。该模型量化的浮力和通流引起的质量和热量传递，产生一个可靠的预测光盘和空气温度。该模型考虑了双重效果的通流：被夹带到冷的径向羽流直接和创建一个环形涡在径向较低的区域的空腔。考虑到低Ro时的流动逆转效应，空腔和通流之间的质量交换与浮力诱导区径向羽流中的质量流量有关。该模型使用在Bath压缩机腔体试验台中收集的数据进行验证，并可纳入发动机设计规范中，以稳健地计算压缩机转子的热应力和膨胀，从而有助于更有效的发动机设计。
Accurate prediction of heat transfer in compressor cavities is crucial to the design of efficient and reliable aircraft engines. The heat transfer affects the thermal expansion of the compressor rotor and, in turn, the tip clearance of the compressor blades. This article presents a novel, physically based predictive theoretical model of heat transfer and flow structure in an open compressor cavity, which can be used to accurately calculate disc temperatures. The radially higher region of the cavity is dominated by buoyancy effects created by the temperature difference between the hot mainstream flow and the axial throughflow used to cool the turbine. Strong interaction between the air in the cavity and this throughflow creates a mixing region at low radius. For a given geometry, the heat transfer and flow physics are governed by four parameters: the rotational Reynolds number R e ϕ, the buoyancy parameter βΔT, the compressibility parameter χ, and the Rossby number Ro. The model quantifies both the buoyancy-and throughflow-induced mass and heat transfer, producing a reliable prediction of the disc and air temperatures. The model takes into account a twofold effect of the throughflow: being entrained into the cold radial plumes directly and creating a toroidal vortex in the radially lower region of the cavity. The exchange of mass between the cavity and throughflow is related to the mass flowrate in the radial plumes in the buoyancy-induced region, considering the effect of flow reversal at low Ro. The model is validated using data collected in the Bath compressor cavity rig and can be incorporated in engine design codes to robustly compute the thermal stress and expansion of the compressor rotor, contributing to more efficient engine designs.