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针对在存在换热的情况下理想绝热容腔模型瞬态响应预测误差大的现状,提出一种考虑换热对容腔瞬态响应影响的非绝热单孔容腔零维瞬态建模方法。通过研究影响气体与容腔壁面换热的因素,采用量纲分析推导了与换热相关的特征数方程,利用CFD数值模拟确定特征数方程的具体函数形式,显式表达了绝热容腔模型未考虑的换热项,建立了非绝热单孔容腔零维模型。通过与数值模拟进行对比分析,结果表明:(1)非绝热容腔零维瞬态模型与CFD三维瞬态数值模拟计算的压力和温度的响应规律吻合很好,最大相对误差不超过0.8%,验证了模型的准确性和建模方法的可行性;(2)绝热容腔零维模型计算结果较CFD数值模拟结果的最大相对误差达6%,表明非绝热模型较绝热模型能够更精确地反映容腔真实响应规律。此外,该模型与CFD数值模拟相比,在1%的精度水平下,降低了三个维度,也大幅降低了容腔瞬态响应模拟的计算量,可以有效地支撑航空发动机空气系统中的容腔高精度建模。
Aiming at the situation that the prediction error of ideal thermal insulation cavity model is large in the presence of heat transfer, a zero-dimensional transient modeling method for non-thermal isolated single-hole cavity considering the influence of heat transfer on the transient response of the cavity is proposed. By studying the factors that affect the heat transfer between the gas and the wall of the cavity, dimension equations were deduced for the characteristic equations related to heat transfer. The CFD numerical simulation was used to determine the specific function form of the eigenvalue equation. The adiabatic cavity model was explicitly expressed Considering the heat exchange term, a non-adiabatic single-hole cavity zero-dimensional model was established. Comparing with the numerical simulation, the results show that: (1) The response law of pressure and temperature in non-adiabatic cavity with zero-dimensional transient model and CFD three-dimensional transient numerical simulation are in good agreement with the maximum relative error less than 0.8% The accuracy of the model and the feasibility of the modeling method are verified. (2) The maximum relative error between the calculated results of the zero-dimensional model of adiabatic cavity and the CFD numerical simulation results is 6%, indicating that the non-adiabatic model can reflect more accurately than the adiabatic model True response to the law of the cavity. In addition, compared with CFD numerical simulation, the model reduces three dimensions at 1% accuracy, greatly reduces the computational load of cavity transient response simulation, and can effectively support the capacity of aeroengine air system Cavity high-precision modeling.