A mathematical model was developed to predict the maximum heat transfer capacity of high temperature heat pipe with triangular grooved wick. The effects of the inclination angle and geometry structure were considered ...A mathematical model was developed to predict the maximum heat transfer capacity of high temperature heat pipe with triangular grooved wick. The effects of the inclination angle and geometry structure were considered in the proposed model.Maximum heat transfer capacity was also investigated experimentally. The model was validated by comparing with the experimental results. The maximum heat transfer capacity increases with the vapor core radius increasing. Compared with the inclination angle of0°, the maximum heat transfer capacity increases at the larger inclination angle, and the change with temperature is larger. The performance of heat pipe with triangular grooved wick is greatly influenced by gravity, so it is not recommended to be applied to the dish solar heat pipe receiver.展开更多
A thermal model for a heat pipe with axially swallow-tailed microgrooves is developed and analyzed numerically to predict the heat transfer capacity and total thermal resistance.The effect of heat load on the axial di...A thermal model for a heat pipe with axially swallow-tailed microgrooves is developed and analyzed numerically to predict the heat transfer capacity and total thermal resistance.The effect of heat load on the axial distribution of capillary radius,and the effect of working temperature and wick structure on the maximum heat transfer capability,as well as the effect of the heat load and working temperature on the total thermal resistance are all investigated and discussed.It is indicated that the meniscus radius increases non-linearly and slowly at the evaporator and adiabatic section along the axial direction,while increasing drastically at the beginning of the condenser section.The pressure difference in the vapor phase along the axial direction is much smaller than that in the liquid phase.In addition,the heat transfer capacity is deeply affected by the working temperature and the size of the wick.A groove wick structure with a wider groove base width and higher groove depth can enhance the heat transfer capability.The effect of the working temperature on the total thermal resistance is insignificant;however,the total thermal resistance shows dependence upon the heat load.In addition,the accuracy of the model is also verified by the experiment in this paper.展开更多
It is the basic requirement of the synergetic exploitation of deep mineral resources and geothermal resources to arrange the heat transfer tube in filling body. The heat release performance of filling body directly im...It is the basic requirement of the synergetic exploitation of deep mineral resources and geothermal resources to arrange the heat transfer tube in filling body. The heat release performance of filling body directly impacts on the exploiting efficiency of geothermal energy. Based on heat transfer theory, a three-dimensional unsteady heat transfer model of filling body is established by using FLUENT simulation software. Taking the horizontal U-shaped buried pipe as research object, the variation of temperature field in filling body around buried pipe is analyzed during the heat release process of filling body;the initial temperature of filling body, the diameter of buried pipe, the inlet temperature and inlet velocity of heat transfer fluid influencing of coupling heat transfer, which exists between heat transfer fluid and surrounding filling body within a certain axial distance of buried tube, and influencing of temperature difference between inlet and outlet of heat transfer fluid and on heat transfer performance of filling body are also discussed. It not only lays a theoretical foundation for the synergetic exploitation of mineral resources and geothermal energy in deep mines, but also provides a reference basis for the arrangement of buried pipes in filling body as well as the selection of working conditions for heat transfer fluid.展开更多
The earth to fluid pipe(ETFP)system has been widely applied to various energy engineering.The numerical model of the heat transfer process in the ETFP system with a shallow-buried horizontal or a deep-buried vertical ...The earth to fluid pipe(ETFP)system has been widely applied to various energy engineering.The numerical model of the heat transfer process in the ETFP system with a shallow-buried horizontal or a deep-buried vertical U-shape pipe adopted in practical engineering was established and the model distinctions were pointed out.The comparison of the thermal performance between the two types of ETFP system under various schemes was conducted on the basis of numerical prediction.The results showed that the thermal parameters of the ETFP system with a shallow-buried horizontal pipe were influenced by the inlet velocity and ground temperature obviously.The variation of the fluid temperature was smooth and the thermal influence zone was limited under the fixed conditions.The proper intermittent operation scheme reduced 53.1%outlet fluid temperature rising.By contrast,the fluid temperature in the ETFP system with a deep-buried vertical U-shape pipe varied dramatically with the operation conditions.The intermittent operation scheme with a relatively short interval led to a less temperature fluctuation of soil around the pipe.The intermittent scheme is beneficial to the recovery of the thermal condition of soil around the U-shape pipe.These results indicated a stark difference in thermal performance between the two types of system.The study can provide guidance for the selection and operation of ETFP system in practical heat exchange engineering.展开更多
基金Project(51076062)supported by the National Natural Science Foundation of China
文摘A mathematical model was developed to predict the maximum heat transfer capacity of high temperature heat pipe with triangular grooved wick. The effects of the inclination angle and geometry structure were considered in the proposed model.Maximum heat transfer capacity was also investigated experimentally. The model was validated by comparing with the experimental results. The maximum heat transfer capacity increases with the vapor core radius increasing. Compared with the inclination angle of0°, the maximum heat transfer capacity increases at the larger inclination angle, and the change with temperature is larger. The performance of heat pipe with triangular grooved wick is greatly influenced by gravity, so it is not recommended to be applied to the dish solar heat pipe receiver.
基金Supported by the 11th Five Year National Science and Technology Support Key Project of China(2008BAJ12B02)
文摘A thermal model for a heat pipe with axially swallow-tailed microgrooves is developed and analyzed numerically to predict the heat transfer capacity and total thermal resistance.The effect of heat load on the axial distribution of capillary radius,and the effect of working temperature and wick structure on the maximum heat transfer capability,as well as the effect of the heat load and working temperature on the total thermal resistance are all investigated and discussed.It is indicated that the meniscus radius increases non-linearly and slowly at the evaporator and adiabatic section along the axial direction,while increasing drastically at the beginning of the condenser section.The pressure difference in the vapor phase along the axial direction is much smaller than that in the liquid phase.In addition,the heat transfer capacity is deeply affected by the working temperature and the size of the wick.A groove wick structure with a wider groove base width and higher groove depth can enhance the heat transfer capability.The effect of the working temperature on the total thermal resistance is insignificant;however,the total thermal resistance shows dependence upon the heat load.In addition,the accuracy of the model is also verified by the experiment in this paper.
基金Projects(51974225,51874229,51674188,51904224,51904225,51504182) supported by the National Natural Science Foundation of ChinaProjects(2018JM5161,2018JQ5183,2015JQ5187) supported by the Natural Science Basic Research Plan of Shaanxi,China
文摘It is the basic requirement of the synergetic exploitation of deep mineral resources and geothermal resources to arrange the heat transfer tube in filling body. The heat release performance of filling body directly impacts on the exploiting efficiency of geothermal energy. Based on heat transfer theory, a three-dimensional unsteady heat transfer model of filling body is established by using FLUENT simulation software. Taking the horizontal U-shaped buried pipe as research object, the variation of temperature field in filling body around buried pipe is analyzed during the heat release process of filling body;the initial temperature of filling body, the diameter of buried pipe, the inlet temperature and inlet velocity of heat transfer fluid influencing of coupling heat transfer, which exists between heat transfer fluid and surrounding filling body within a certain axial distance of buried tube, and influencing of temperature difference between inlet and outlet of heat transfer fluid and on heat transfer performance of filling body are also discussed. It not only lays a theoretical foundation for the synergetic exploitation of mineral resources and geothermal energy in deep mines, but also provides a reference basis for the arrangement of buried pipes in filling body as well as the selection of working conditions for heat transfer fluid.
基金supported by the National Natural Science Foundation of China(No.51606114)the Science and Technology Commission of Shanghai Municipality(No.18020501000).
文摘The earth to fluid pipe(ETFP)system has been widely applied to various energy engineering.The numerical model of the heat transfer process in the ETFP system with a shallow-buried horizontal or a deep-buried vertical U-shape pipe adopted in practical engineering was established and the model distinctions were pointed out.The comparison of the thermal performance between the two types of ETFP system under various schemes was conducted on the basis of numerical prediction.The results showed that the thermal parameters of the ETFP system with a shallow-buried horizontal pipe were influenced by the inlet velocity and ground temperature obviously.The variation of the fluid temperature was smooth and the thermal influence zone was limited under the fixed conditions.The proper intermittent operation scheme reduced 53.1%outlet fluid temperature rising.By contrast,the fluid temperature in the ETFP system with a deep-buried vertical U-shape pipe varied dramatically with the operation conditions.The intermittent operation scheme with a relatively short interval led to a less temperature fluctuation of soil around the pipe.The intermittent scheme is beneficial to the recovery of the thermal condition of soil around the U-shape pipe.These results indicated a stark difference in thermal performance between the two types of system.The study can provide guidance for the selection and operation of ETFP system in practical heat exchange engineering.
