Study On Thermal Physical Properties Of Hydrate

Nowadays,most experiments about gas hydrate are based on time domain.With the development of the freestanding sensors based on 3? method,the thermal properties of gas hydrate can be easily measured in frequency domain.This thesis used Pt wire linear sensor and freestanding membranous sensor based on 3? method to measure the thermal properties of methane hydrate and carbon dioxide hydrate,which were compounded with high pressure and low temperature.Analyzing the effects of the structure of sensors on experimental results.For Pt wire linear sensor,the effects of ratio of length and diameter,heat capacity and end effect were discussed.For freestanding membranous sensor,the effects of the width of Ni belt and the depth of the Kapton film on linear heat source approximation degree and two dimensional thermal diffusion effect were analyzed.Besides the theoretical analysis,the thermal conductivity and thermal diffusivity of carbon dioxide were measured through Pt wire linear sensor in the transcritical state.The changes of thermal conductivity of carbon dioxide with pressure and temperature were analyzed.The thermal conductivity and thermal diffusivity of methane hydrate were measured through freestanding linear sensor based on 3? method.Also,the thermal boundary resistance of the experimental system were obtained.Both Pt wire sensor and freestanding linear sensor were used to measuring the thermal properties of carbon dioxide hydrate and the results obtained respectively were compared to prove the feasibility of the two methods.The molecular dynamic was applied to calculate the thermal conductivity of methane hydrate and the effect of the intermolecular forces on the thermal conductivity of methane hydrate was obtained.The simulated results were compared with experimental results to find the differences and explain the reasons.