【作者】 孟令军；

【导师】 陈国邦；

【作者基本信息】 浙江大学 ， 制冷及低温工程， 2008， 硕士

【摘要】 ~3He-~4He混合物是一种特殊的低温流体混合物，其在低温工程、基础物理学和空间技术等领域有重要应用。这些应用大多需要~3He-~4He混合物热物性数据的支持。虽然有关~3He-~4He混合物的热物性测量和理论研究在过去60年已在4K以下大量开展，但是其固-液相边界曲线特征方程、宽范围混合物模型以及热物性计算程序一直处于空缺状态。为了解决这个制约~3He-~4He混合物各项应用获得进一步发展的瓶颈，本文以研究~3He-~4He混合物相平衡曲线，流体区热力性质及混合物模型为目标，开展了以下工作：1．收集了大量有关~3He-~4He混合物的文献，整理了其中的PVT和VLE(气-液相平衡)热力学性质数据，极大地完善了~3He-~4He混合物电子文献库和数据库；并将大量数据绘制成图表，以便直观地反映~3He-~4He混合物的性质变化趋势，方便了之后的研究工作。2．基于实验数据，通过独立编写的人工神经网络程序以较高的精度预测了整个混合物凝固压力曲面，在国际上首次提出了0．4K-5K温区，0-1全组分范围的显式混合物凝固压力特征方程，其精度满足工程精度要求。3．在分析~3He-~4He混合物特殊性质以及亥姆霍兹能混合模型优势的基础上，提出了在亥姆霍兹能框架内发展~3He-~4He混合物模型的研究思路。4．基于VLE实验数据情况和人工神经网络理论，在亥姆霍兹能方程理论框架内对发展VLE性质辅助方程进行了可行性分析并给出了具体的实施步骤。5．在国际上获得了第一个可付诸工程应用的亥姆霍兹能形式~3He-~4He混合物模型。该模型能较好地预测8K-13K温区~3He浓度较低时的~3He-~4He混合物PVT性质，对于13K以上的区域，计算误差能进一步降低。该模型对于进一步提高采用~3He-~4He混合物为工质的单级G-M型脉管制冷机的设计制造和性能预测水平，有着积极的促进作用。更多还原

【Abstract】 ~3He-~4He mixture is a special cryogenic fluid mixture, with its applications covering cryogenic engineering, fundamental physics and space technology, etc. Optimum system design generally requires knowledge of ~3He-~4He mixture properties. For ~3He-~4He, however, though some theoretical work has been performed and many state properties have been individually measured, the corresponding mixture model explicit in Helmholtz energy form and pressure-explicit state equations along the phase-equilibrium boundaries have never been obtained. Further, no rounded thermodynamic diagrams and modern computer programs are available to calculate the thermophysical properties of ~3He-~4He mixture. In order to provide thermophysical property standards for this mixture and to remove the obstacle for the further development of its applications, the present work focuses on the following sessions:1. Extensive literature survey on ~3He-~4He mixture has been performed and the thermodynamic data have been sorted out, which makes the electronic reference bank and electronic data bank much more plentiful and complete. At the same time, abundant tables and figures have been obtained, which provides a direct view of the trend of all kinds of thermophysical properties.2. Based on experimental data and thermodynamics, the freezing pressure surface of ~3He-~4He mixture has been predicted with relatively high accuracy, using Artificial Neural Network theory. A state equation of freezing pressure covering the whole composition range has been develop for the mixture and the accuracy of the equation between 0.4K-5K meets the engineering standard.3. After examining the experimental data and Artificial Neural Network theory, a detailed flexibility analysis has been carried out on the development of Vapor-Liquid Equilibrium Ancillary Equation within the framework of Helmholtz Energy State Equation and specific procedures outlined.4. Following a discussion on peculiar properties of ~3He-~4He mixture and the advantage of mixture model explicit in Helmholtz energy form, a development strategy concerning ~3He-~4He mixture within the framework of Helmholtz Energy State Equation has been put forward and evaluated.5. The first practical ~3He-~4He mixture model explicit in Helmholtz energy form in the world has been developed. The model’s accuracy concerning PVT property of the mixture between 8K and 13K is fairly satisfactory when the composition of ~3He is below 50%, and that in the region above 13K can be enhanced to a higher degree. This practical mixture model can facilitate the enhancement of design and theoretical prediction ability of single-stage G-M type Pulse Tube Refrigerator.更多还原