旋转帽罩热管防冰性能数值模拟研究
发布时间：2018-07-17 17:37
【摘要】：在一定的飞行条件和气象条件下,航空发动机的进气部件,如进气道、风扇叶片、支板、旋转帽罩等会出现结冰现象。如果冰层快速增加,减小进气道气流流通的截面积,导致航空发动机性能恶化。旋转帽罩结冰严重时,直接会增加旋转帽罩的重量,增大发动机负荷,会使发动机不能正常工作。如果发生冰脱落,甚至会危及发动机的安全。所以,为了防止帽罩结冰,必须对帽罩进行防冰处理。与热气防冰、憎水涂层防冰等方式相比,旋转热管防冰具有独特的优势。但目前对旋转热管内部工质流动和传热机理认识仍不十分清楚,有待进一步研究。为了揭示旋转热管内部工质的复杂流动和准确描述旋转热管内部工质流动和传热特性,本文采用VOF多相流模型,将液体和蒸气作为一个整体的区域,建立基于完整Navier-Stokes方程组的二维数学模型,以揭示更多的细节特征和旋转热管内部流动和传热特性规律。本文采用CFD软件结合气液界面追踪程序和导热定律的界面相变模型,对轴向旋转热管内部工质流动和传热特性进行了数值模拟研究。分别研究了纯导热蒸发模型和考虑自然对流的蒸发模型,并和实验结果进行了对比,以探索相变模型的优劣。采用了考虑自然对流的相变模型,分析了传热量、充液量、转速和工质等参数对旋转热管流动和传热特性的影响规律。研究表明:蒸发段采用纯导热蒸发模型,其数值模拟结果和实验值误差较大。考虑自然对流的相变模型,其数值模拟结果和实验值吻合很好,验证了该模型的可靠性和准确性。传热量对传热性能影响较小;转速越高,传热性能越强;充液量对传热性能影响较小,这和文献中的实验结论一致;工质的物性参数对旋转热管传热性能影响显著。全锥度旋转热管和典型旋转热管具有相似的工作特性。和典型旋转热管相比,全锥度旋转热管具有更好的传热性能和其冷凝段具有更好的均温性。基于之前的旋转热管研究工作,采用了考虑自然对流的相变模型,对旋转帽罩热管防冰装置进行了防冰性能的数值模拟研究。研究发现,热载荷对整个装置的传热性能影响较小,防冰热载荷对帽罩表面均温性有影响;转速越高,传热性能越强,转速对帽罩表面均温性影响较小;导热材料的导热系数越大,帽罩表面均温性越好。另外,在防冰工况下,润滑油和环境温差在100℃以上,而维持帽罩表面温度在结冰温度以上时,蒸发段和帽罩表面温差远远低于这个值,表明以润滑油作为热源的旋转热管具有帽罩防冰的可行性。本文形成了基于数值计算的旋转帽罩热管防冰装置的设计方法,可以用来研究不同结构、不同工作参数对其影响规律,大大减少了人力、物力和财力,从而为工程设计提供了支持和指导。
[Abstract]:Under certain flight and weather conditions, the aero-engine intake components, such as intake ports, fan blades, branch plates, rotating cap covers and so on, will freeze. If the ice layer increases rapidly, the cross section of inlet airflow will be reduced, which will result in the deterioration of aero-engine performance. When the rotation cap freezes seriously, it will directly increase the weight of the rotating cap cover and increase the engine load, which will make the engine unable to work properly. If ice comes off, it will even endanger the safety of the engine. Therefore, in order to prevent the cap from freezing, the cap must be ice-proof treatment. Compared with hot air ice protection and hydrophobic coating, rotating heat pipe has unique advantages. However, the mechanism of fluid flow and heat transfer in rotating heat pipe is still unclear, which needs further study. In order to reveal the complex flow of the working fluid in the rotating heat pipe and accurately describe the flow and heat transfer characteristics of the working fluid in the rotating heat pipe, a VOF multiphase flow model is used in this paper, in which the liquid and steam are regarded as a whole region. A two-dimensional mathematical model based on holonomic Navier-Stokes equations was established to reveal more detailed characteristics and the characteristics of flow and heat transfer in rotating heat pipe. In this paper, the fluid flow and heat transfer characteristics in axial rotating heat pipe are numerically simulated by using CFD software combined with the gas-liquid interface tracing program and the interfacial phase transition model of heat conduction law. The pure heat conduction evaporation model and the evaporation model considering natural convection are studied, and the results are compared with the experimental results to explore the advantages and disadvantages of the phase transition model. A phase transition model considering natural convection is used to analyze the influence of heat transfer rate, liquid charge, rotational speed and working fluid on the flow and heat transfer characteristics of rotating heat pipe. The results show that the numerical simulation results of the evaporative section with pure heat conduction evaporation model are quite different from the experimental data. The numerical simulation results are in good agreement with the experimental data, and the reliability and accuracy of the model are verified. The effect of heat transfer quantity on heat transfer performance is small; the higher the rotational speed, the stronger the heat transfer performance; the smaller the effect of liquid charge on heat transfer performance, which is consistent with the experimental results in literature; and the significant effect of the physical parameters of working fluid on the heat transfer performance of rotating heat pipe. The full taper rotary heat pipe and the typical rotary heat pipe have similar working characteristics. Compared with the typical rotary heat pipe, the full taper rotating heat pipe has better heat transfer performance and better uniform temperature in the condensation section. Based on the previous research work of rotating heat pipe, a phase change model considering natural convection was used to simulate the anti-ice performance of the heat pipe with rotating cap cover. It is found that the heat load has little effect on the heat transfer performance of the whole device, the anti-ice thermal load has an effect on the uniform temperature of the cap cover surface, and the higher the rotational speed, the stronger the heat transfer performance, and the less the effect of the speed on the uniform temperature property of the cap cover surface. The larger the coefficient of thermal conductivity is, the better the average temperature of the cap is. In addition, when the temperature difference between lubricating oil and ambient temperature is above 100 鈩，
本文编号：2130430
[Abstract]:Under certain flight and weather conditions, the aero-engine intake components, such as intake ports, fan blades, branch plates, rotating cap covers and so on, will freeze. If the ice layer increases rapidly, the cross section of inlet airflow will be reduced, which will result in the deterioration of aero-engine performance. When the rotation cap freezes seriously, it will directly increase the weight of the rotating cap cover and increase the engine load, which will make the engine unable to work properly. If ice comes off, it will even endanger the safety of the engine. Therefore, in order to prevent the cap from freezing, the cap must be ice-proof treatment. Compared with hot air ice protection and hydrophobic coating, rotating heat pipe has unique advantages. However, the mechanism of fluid flow and heat transfer in rotating heat pipe is still unclear, which needs further study. In order to reveal the complex flow of the working fluid in the rotating heat pipe and accurately describe the flow and heat transfer characteristics of the working fluid in the rotating heat pipe, a VOF multiphase flow model is used in this paper, in which the liquid and steam are regarded as a whole region. A two-dimensional mathematical model based on holonomic Navier-Stokes equations was established to reveal more detailed characteristics and the characteristics of flow and heat transfer in rotating heat pipe. In this paper, the fluid flow and heat transfer characteristics in axial rotating heat pipe are numerically simulated by using CFD software combined with the gas-liquid interface tracing program and the interfacial phase transition model of heat conduction law. The pure heat conduction evaporation model and the evaporation model considering natural convection are studied, and the results are compared with the experimental results to explore the advantages and disadvantages of the phase transition model. A phase transition model considering natural convection is used to analyze the influence of heat transfer rate, liquid charge, rotational speed and working fluid on the flow and heat transfer characteristics of rotating heat pipe. The results show that the numerical simulation results of the evaporative section with pure heat conduction evaporation model are quite different from the experimental data. The numerical simulation results are in good agreement with the experimental data, and the reliability and accuracy of the model are verified. The effect of heat transfer quantity on heat transfer performance is small; the higher the rotational speed, the stronger the heat transfer performance; the smaller the effect of liquid charge on heat transfer performance, which is consistent with the experimental results in literature; and the significant effect of the physical parameters of working fluid on the heat transfer performance of rotating heat pipe. The full taper rotary heat pipe and the typical rotary heat pipe have similar working characteristics. Compared with the typical rotary heat pipe, the full taper rotating heat pipe has better heat transfer performance and better uniform temperature in the condensation section. Based on the previous research work of rotating heat pipe, a phase change model considering natural convection was used to simulate the anti-ice performance of the heat pipe with rotating cap cover. It is found that the heat load has little effect on the heat transfer performance of the whole device, the anti-ice thermal load has an effect on the uniform temperature of the cap cover surface, and the higher the rotational speed, the stronger the heat transfer performance, and the less the effect of the speed on the uniform temperature property of the cap cover surface. The larger the coefficient of thermal conductivity is, the better the average temperature of the cap is. In addition, when the temperature difference between lubricating oil and ambient temperature is above 100 鈩，
本文编号：2130430
本文链接：https://www.wllwen.com/kejilunwen/hangkongsky/2130430.html
