横流环境中冷却水排放浮升规律

Study of buoyant rule of cooling waterdischarged in cross flow

冷却水排放浮升规律对红外隐身的研究具有重要意义。冷却水排放过程可以简化为横流环境中的水平热射流过程,本文在有限体积法的基础上采用Simple算法和Realizable k-ε湍流模型对热射流浮升过程建立三维数学模型,并进行数值模拟。数值模拟结果显示热射流三维浮升轨迹线与文献中的实验结果吻合良好,浮升迹线验证了该模型和方法的准确性。利用该数学模型进一步计算比较了不同流速比和不同环境流速下的浮升规律和温度分布特性,分析得到了流速比和环境流速对热射流浮升轨迹和中心温度的影响规律,为基于红外特征的冷却水排放规律研究提供了理论依据。

The cooling water discharging law plays an important role in the study of infrared stealth. The cooling water discharge process can be condensed into the horizontal thermal jet in cross flow. According to the theory of computational fluid dynamics, the mathematical model of round horizontal thermal jets in cross flow is established. The 3D numerical simulation of thermal jets based on finite volume method is achieved by using the Realizable k-a turbulence model and the Semi-implicit method for pressure linked equations, and the three-dimensional trajectory of thermal jet are obtained. The rationality of analysis method is approved by comparing calculation value with experimental value. Both buoyant law and temperature distributions in thermal jets are studied through the numerical experiments conducted under different velocity ratios and different cross-flow velocity with same ratios. As a result, the impacts of these conditions on buoyant trajectory and the center temperature are found, and the theoretic bases are provided for the study of cooling water discharging law based on infrared characteristics.