跨能域/跨尺度机载电动静液作动器的油液温升机理及抑制方法

High power density and lower cooling capacity of airborne electro-hydrostatic actuator (EHA) lead to the higher oil temperature, which is a serious threat to flight safety, so the higher oil temperature is an urgent issue. At present, the method of simplifying or ignoring EHA nonlinear heat factor reduces the thermodynamic modeling accuracy; the method of installing radiator to expand the cooling area leads to increasing sharply EHA volume and weight. According to the deficiency, the project based on thermodynamic accurate modeling, explores the method of improving shell heat dissipation rate to suppress too high oil temperature rise. Detailed research coupling relationship between leakage creating heat and friction creating heat, to establish thermodynamic model of the whole coupling non-isothermal hydraulic friction pair；research thermodynamic accurate modeling problem of hydraulic system in multi-energy domains (electric, magnetic, machine, hydraulic), multi-scale (μm→dm) and nonlinear heating model containing such as friction pair, to reveal oil temperature rise mechanism；research the problem of enhancing heat transfer by passive device when the air is in the laminar flow, to put forward the method of swallow eddy heat transfer inducement and develop EHA thermal design; finally, perform experiment in the ground and upper air test bench to verify the oil temperature rise mechanism and suppression method. The study of project can promote thermodynamics research and development in the complicated mechanical, electrical and hydraulic system; swallow eddy heat transfer inducement can greatly improve the shell heat dissipation rate with no external power through the reasonable layout of fin, which is of great theoretical significance and engineering application value to the airborne equipment with the strict request in weight and reliability.

机载电动静液作动器（EHA）功率密度大、散热能力差的特点导致其油液温度过高，危及飞行安全，因此油温过高是亟待解决的问题。目前简化或忽略EHA非线性生热因素降低了热力学建模精度；安装散热片扩大散热面积导致EHA体积和重量大幅增加。针对以上不足，项目基于热力学精确建模，探索提高壳体热耗散率方法来抑制油温过高。重点研究泄漏生热和摩擦生热的耦合关系，建立全耦合非等温液压摩擦副热力学模型；研究跨能域（电、磁、机、液）、跨尺度（μm→dm）、包含摩擦副等非线性生热模型的液压系统热力学精确建模问题，揭示EHA油液温升机理；研究空气层流时无源强化换热问题，提出燕涡导换热方法，并进行EHA热设计；最后进行地面和高空模拟实验验证。项目研究可推动复杂机电液系统的热力学研究与发展；燕涡导换热方法无需外部动力，通过布置翅片可大幅提高壳体热耗散率，对重量和可靠性有严格要求的机载设备来说具有重大理论意义和工程应用价值。

电动静液作动器（Electro-Hydrostatic Actuator，EHA）是多电飞机关键子系统之一，将电能根据飞行指令转换为机械能操纵飞行舵面，在能量传递和转换过程中发生能量损失、产生热量。产生的热量一部分滞留在EHA壳体的较小密闭容腔内，散热面积小、散热能力差，导致EHA液压油温度过高、功能失效，危及飞行安全，因此油液温度控制是EHA亟待突破的关键技术之一。.项目以EHA为研究对象，展开四个方面研究，即①液压摩擦副热力学建模及生热机理研究；②跨能域/跨尺度液压系统热力学统一建模及油液温升机理；③空气层流时提高壳体热耗散率的无源强化换热方法；④试验研究。.项目创新性成果如下：.1）提出了跨能域（电能、机械能、液压能、热能）、变参数（电机电阻、液压油密度、黏度）EHA的“三维+一维+三维”热力学建模方法，解决了复杂机电液系统的热力学精确建模问题，实验验证了方法的正确性；.2）揭示了EHA油液温升规律：① EHA的电机和油箱温升主要与载荷谱有关，与环境温度相关度低；②电机转速对EHA油液温升影响较大，载荷谱对应电机转速越高，油液温升越大；③ EHA的油液温度随着工作频率增加而升高，EHA达到平衡点时，在误差允许范围内增大控制周期，有利于控制系统油液温度；.3）提出了一种新型基于导流翼型散热翅片的无源强化散热方法，无需外部动力，在不降低系统可靠性情况下通过破坏空气层流为湍流，强化壳体表面温度较高区域的散热，具有更好的散热效果和广泛适用性；.4）发明了一种新型导流翼型散热翅片，揭示了导流翼片倾角对散热效果的影响规律，倾角为20.7º的散热翅片散热效果最好；在4.2m/s风速工况下，新型导流翼型散热翅片相比传统的直翅片散热效果提升了10%左右，但当风速超过11m/s后新型散热片的散热效果要低于传统直翅片。.项目研究推动了复杂机电液系统的热力学建模和仿真，导流翼型换热方法无需外部动力，通过布置翅片可大幅提高壳体热耗散率，对重量和可靠性有严格要求的机载设备来说具有重大理论意义和工程应用价值。