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Transport Properties of Helium-3 and Thermodynamic Properties of Helium-3/Helium-4 Mixtures

Author: WangXiaoJian
Tutor: WangRuZhu；HuangYongHua
School: Shanghai Jiaotong University
Course: Refrigeration and Cryogenic Engineering
Keywords: helium-3 helium-4 mixtures transport properties equation of state
CLC: O572.35
Type: Master's thesis
Year: 2011
Downloads: 41
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Abstract

Helium-3 is a rare natural gas, but is widely used in many fields with its unique properties. So it is very important and necessary to understand its thermal physical properties. Now there has been systematic research of its thermodynamic properties, but no comprehensive research of its transport properties. However, there are many published papers about the experimental research and many data of measurements in the past 50 years. Based on these research works, breakthrough of its transport properties has made. Considering some use of helium-3 under some circumstance and its expensive price, so it makes sense that using mixtures of helium-3 and helium-4 to replace helium-3. So the thermodynamic properties are important for us to determine the idea. The present work focuses on the following sessions:1. Research work for transport properties of helium-3. A lot of experimental measurements and theoretical calculations for the transport properties such as surface tension, thermal conductivity and viscosity have been collected into a searchable database. For the sake of consistency, the outdated units and temperature scales of the reference data were converted to SI units and ITS-90 scale. Based on the previous work, surface tension, thermal conductivity and viscosity are investigated in the relationship of temperature and pressure. The equation of surface tension is developed from the absolute 0 degree to the critical temperature 3.3157 K. Considering scarce measurement of thermal conductivity and viscosity above 20 K, the predict data are calculated from the principle of corresponding states. Combine the experimental data, two equations for the thermal conductivity and viscosity are developed for the temperature from 3 mK to 300 K and pressure up to 20 MPa using chebyshev polynomials.2. Research of thermodynamic properties of ~3He-~4He mixtures along the vapor-liquid line. ~3He-~4He mixtures have unique superfluid transition and phase separation properties, so their phase diagram is more complicated than normal fluids. Base on the experimental measurements, the accurate phase diagram is built using equations. The research work of density and pressure in the dew and boiling line are summed up. The boiling pressure is calculated using spline difference. And the boiling density equation is developed form 0.5 K to the critical temperature. The critical parameters are determined by the functions related with 3He concentration. The relation between saturated heat specific and temperature is defined by equations in small temperature range.3. State equations of the ~3He-~4He mixtures. Simply make a introduction about the phase diagram in high pressure and the state equation of liquid ~3He-~4He mixtures in the temperature from 2.5 to 4.5 K. A new state equation of gas ~3He-~4He mixtures in temperature from 4.5 to 14 K is developed. The deviation between the measurements and calculated data mostly is within 2%, and 6% near the critical point. Considering that there is small deviation of density between ~3He and ~4He above 20 K, so the p-V-T date above 20 K is predicted by linear interpolation. So theρ-T diagram of five mixtures with which the concentration of ~3He are respectively 0.2, 0.4, 0.5, 0.6 and 0.8 are built in temperature form 2.5 to 300 K and pressure up to 2.5MPa.

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