【作者】 王勇；

【导师】 戴景民； 萧鹏；

【作者基本信息】 哈尔滨工业大学 ， 仪器科学与技术， 2019， 博士

【摘要】 在科学技术的发展中,温控技术发挥着十分重要的作用,尤其在军事领域,受到了广泛的重视。对于导弹来说,需要在不被探测的情况下实现精确打击,因此,导弹表面均涂覆有防止雷达探测的吸波材料。导弹飞行过程中,与空气不断摩擦会使表面温度逐渐升高,因此,需要在吸波材料的背面装载温控组件使导弹表面保持恒温,从而实现热红外隐身。在温控技术中,相变材料由于相变温度区间稳定、储能密度高、化学稳定性好等优势,成为温控技术中广泛使用的材料。准确的获得相变材料的传热特性和热物理性质,对温控技术的发展,具有十分重要的意义。温控组件的研究主要包含内部相变材料传热过程研究,以及热导率、相变温度和吸热量等热物性参数的测量。导弹飞行过程中,温控组件可能会出现不同的姿态,温控组件姿态的不同会影响内部相变材料的传热特点,而对于不同姿态的温控组件的传热研究,目前是十分缺乏的。为了检验温控组件产品性能,需要对温控组件的热物性进行测量。由于温控组件的尺寸较大,而且是组件内填充的是能够固液相变的材料,因此,对于这种结构的热物性测量方法和装置也是十分缺乏的。综上,本文开展了相变温控材料热物性理论和实验研究工作。本文研究工作的主要内容如下:(1)针对导弹发射后温控组件存在不同的位置关系问题,建立了不同姿态矩形容器内相变材料的相变传热过程模型,分析不同姿态的温控组件的相变传热特点。考虑加热过程中接触热阻对传热过程的影响,对接触热阻进行修正,使仿真分析中温度的监测点与实验测试温度点的偏差小于7%,并揭示了相变材料储能时间与组件倾斜角度的非线性关系规律。通过正交试验法建立不等水平的正交试验方案,对相变传热过程的影响因素进行了分析。(2)针对导弹发射后温控组件的热物理性质测试问题,提出了温控组件热导率、相变温度和吸热量的测试方法。基于稳态热流法的基本原理,通过标定随温度变化的热流计灵敏系数和接触热阻,建立温控组件热导率测量方法,并推导温控组件中相变材料热导率的计算模型。同时,利用标定得到的热流计吸热量校正系数随温度变化的函数关系,建立温控组件内相变材料总吸热量的计算模型,并给出相变温度的判断方法。(3)针对温控组件产品的热物理性质测量要求,研制了宽温度范围的温控组件产品的热导率、相变温度和吸热量的测量装置。在装置中,设计了两个结构相同的加热板,通过冷板自身的对流辐射散热,提高了冷板的温度范围,解决了目前稳态热流法测试中冷板温度低的问题,实现了温控组件热导率和吸热量测量。同时,根据不同温度下的PID参数自整定结果,提出分段极值约束PID控制方法,减小温度超调。(4)利用本文提出的热物性测量方法和研制的热物性测量装置进行了实验,并进行了不确定度分析。通过对基本材料的热导率的测试,验证了在宽温度范围内,对热流计灵敏系数随温度变化标定的必要性。然后,对容器中的正二十二烷和丁四醇的热物性进行了测试实验,并对实验结果进行了比较和分析,验证了测试方法的可靠性。通过不确定度分析,容器中材料热导率测试的标准不确定度优于3.79%,相变温度测试标准不确定度为0.3°C,吸热量测试标准不确定度为1.99%。更多还原

【Abstract】 With the development of science and technology,temperature control technology plays a very important role and has received widely attention,especially in the military field.For missiles used to attack targets,it is necessary for missiles to attack accurately without being detected.Therefore,surfaces of missiles are coated with electromagnetic wave absorbing material to prevent radar detection.During the missile flight,continuous friction with air will increase the surface temperature gradually.Thus,it is necessary to load temperature control components on the back of absorbing materials to keep the missile surface at a constant temperature so as to realize thermal infrared stealth.In the temperature control technology,phase change materials are widely used because of the advantages of stable phase change temperature range,high energy storage density and good chemical stability.Therefore,it is of great significance for the development of temperature control technology to study the phase change heat transfer characteristics and accurately measure the thermophysical properties of phase change materials.The research of temperature control components mainly includes the study of heat transfer process of internal phase change materials,as well as the measurement of thermophysical parameters such as thermal conductivity,phase change temperature and heat absorption.During the missile flight,the temperature control components may have different postures.The difference in the postures of the temperature control components will affect the heat transfer characteristics of internal phase change material.However,the research on the heat transfer of the temperature control components with different postures is currently very scarce.Besides,in order to test the performance of temperature control components,it is necessary to measure the thermophysical properties of temperature control components.Since the size of the temperature control component is large and the component is filled with solid-liquid phase change material,the methods and devices for measuring thermophysical properties of the component are also very scarce.Therefore,the theoretical and experimental research on the thermophysical properties of phase change temperature control materials has been carried out in this paper.The main research contents of this paper are as follows:(1)In view of the different positions of temperature control components after the missile is launched,a phase change heat transfer model of phase change material in a rectangular container with different inclination angles is established,and the phase change heat transfer characteristics of temperature control components with different inclination angles are analyzed.Considering the influence of contact thermal resistance on heat transfer during the heating process,the contact thermal resistance is corrected,so that the deviation between temperature monitoring points in simulation analysis and experimental temperature points is less than 7%.Furthermore,the non-linear relationship between energy storage time of phase change materials and inclination angles is revealed.Besides,in order to analyze the influencing factors of phase change heat transfer process,different levels of orthogonal test schemes are established.(2)Aiming at the thermophysical properties test of the temperature control components after missile launching,a method for measuring the thermal conductivity,phase change temperature and heat absorption of the temperature control component is proposed.Based on the basic principle of steady-state heat flow method,the thermal conductivity measurement method of temperature control component is established by calibrating the sensitivity coefficient of heat flow meter and contact thermal resistance between specimen and plates varied with temperature change,and the calculation model of thermal conductivity of phase change material in temperature control component is derived.Meanwhile,based on the calibration function of the calibration coefficient of the heat flow meter obtained by calibration experiment varied with temperature change,the calculation model of total heat absorption of phase change material in the temperature control component is established,and the judgment method of phase change temperature is provided.(3)In order to meet the requirements of thermophysical properties measurement of temperature control component products,a device for measuring thermal conductivity,phase change temperature and heat absorption of temperature control component product in a wide temperature range is developed.In this apparatus,two heating plates with the same structure are designed.The upper temperature limit of the cold plate is increased by using the convection and radiation heat dissipation method,which solves the problem of low temperature of the cold plate in steady-state heat flow method.Then,the thermal conductivity and the heat absorption of the temperature control component are measured.At the same time,according to selftuning results of PID parameters at different temperatures,a piecewise extremely constrained PID control method is proposed to reduce temperature overshoot.(4)Experiments are carried out with the thermophysical property measurement method and the designed apparatus proposed in this work,and the uncertainties of the testing results are analyzed.Through the test of the thermal conductivity of basic materials,the necessity of calibrating the sensitivity coefficients of the heat flow meter with temperature change in a wide temperature range is verified.Then,the thermophysical properties of n-docosane and erythritol in the container are measured,and the experimental results are compared and analyzed to verify the reliability of the method.Through the uncertainty analysis of thermophysical parameters for the phase change material in the container,the standard uncertainty of thermal conductivity test is better than 3.79%,the standard uncertainty of phase change temperature test is 0.3 °C,and the standard uncertainty of heat absorption test is 1.99%.更多还原