基于三维实体建模的刷式密封传热机理数值研究

建立了基于三维实体建模的刷式密封传热特性求解模型,在验证数值模型准确性的基础上,分析了刷式密封流场与温度场分布特性,研究了压比、转速、干涉量和热流密度对刷丝最高温度的影响,揭示了刷式密封的传热机理。结果表明:高温区主要集中在末排刷丝与转子面接触位置,刷丝的最高温度随着压比、转速、干涉量和热流密度增加而增大,其中干涉量对刷丝最高温度的影响最为明显。当干涉量从0.1 mm增至0.7 mm时,刷丝的最高温度上升1.61倍;刷式密封热量的主要来源为刷丝与转子表面摩擦产生的热量,其传热形式包括导热和对流换热,摩擦热量通过导热形式进入刷丝和转子,当刷丝与转子之间的接触力增加时,摩擦热量增大,刷丝的最高温度升高,摩擦热量通过对流换热形式在流体和固体之间进行传递,热量散失主要形式为泄漏气流带走部分热量。 

Numerical study on heat transfer mechanism of brush seal based on three-dimensional solid modeling

A model for solving the heat transfer characteristics of brush seals based on three-dimensional solid modeling was established. The distribution characteristics of the flow field and temperature field of the brush seal were analyzed by verifying the accuracy of the numerical model. The influences of the pressure ratio, the rotational speed and the interference on the maximum temperature of the brush wire were studied. The heat transfer mechanism of the brush seal was revealed. The results showed that the end-discharge brush wire and the rotor face were mainly concentrated in the high temperature area of the bristle. The maximum temperature of the brush wire increased with the increase of the pressure ratio, rotational speed and interference, in which the interference had obvious influence on the maximum temperature. When the amount of interference increased from 0.1 mm to 0.7 mm, the maximum temperature increased 1.61 times; The main source of heat of the brush seal was generated by friction between the brush and the rotor surface, the heat transfer form of the brush seal included conduction heat and convection heat exchange. The friction heat flow entered the brush wire bundle and the rotating shaft through the heat conduction form. When the contact force between the brush wire and the rotor increased, the frictional heat flux increased, and the maximum temperature rose. The friction heat flowed through the heat transfer between fluid and solid transmission, and the main form of heat dissipation was the leakage of air taking away part of the heat.