Loop Heat Pipe(LHP)is an efficient two-phase heat transfer device,which can be used in waste heat recovery,electronics cooling,aerospace and other fields.The wick,the core component of LHP,plays an important role in i...Loop Heat Pipe(LHP)is an efficient two-phase heat transfer device,which can be used in waste heat recovery,electronics cooling,aerospace and other fields.The wick,the core component of LHP,plays an important role in its start-up and operation.In this paper,the wick fabricated by 3D printing technology had uniform and interconnected pores.In the experiment,the position of the parallel vapor removal grooves was always fixed towards the vapor outlet.When the cylindrical wick was placed in the evaporator,the rotation angle relative to its central axis could be changed,thus changing the number and shape of the pores facing the vapor removal grooves.The wick deflection angle represented its change in spatial position relative to the fixed vapor removal grooves.The effect of the wick deflection angles on the heat transfer characteristics of the flat LHP was experimentally investigated.It was found that with the change of deflection angle,the number of pores in the evaporation-oriented zone would also change,which had a significant impact on the start-up process and heat transfer performance of LHP.When the deflection angle was 30°,LHP could start fastest at a low heat load of 20 W and operate stable at a high heat load of 180 W.展开更多
t A series of inline pico hydropower systems,which could be used in confined space,especially for water distribution networks(WDNs),was designed and investigated.The turbine with an eye-shaped vertical water baffle wa...t A series of inline pico hydropower systems,which could be used in confined space,especially for water distribution networks(WDNs),was designed and investigated.The turbine with an eye-shaped vertical water baffle was developed to evaluate the hydraulic performance.A three-dimensional dynamic mesh was employed and the inlet velocity was considered as the inlet boundary condition,whereas the outlet boundary was set as the outflow.Then,numerical simulations were conducted and the standard k-εturbulence model was found to be the best capable of predicting flow features through the comparison with the experimental results.The effects of the opening diameter of the water baffle and installation angle of the rotor on the flow field in the turbine were investigated.The results suggested that the water baffle opening at d=30 mm and the rotor at a 52°angle could achieve the highest efficiency of 5.93%.The proper eye-shaped baffle not only accelerates the fluid flow and generates positive hydrodynamic torque,but also eliminates the flow separation.The scheme proposed in this paper can be exploited for practical applications in the water pipelines at various conditions and power requirements.展开更多
文摘Loop Heat Pipe(LHP)is an efficient two-phase heat transfer device,which can be used in waste heat recovery,electronics cooling,aerospace and other fields.The wick,the core component of LHP,plays an important role in its start-up and operation.In this paper,the wick fabricated by 3D printing technology had uniform and interconnected pores.In the experiment,the position of the parallel vapor removal grooves was always fixed towards the vapor outlet.When the cylindrical wick was placed in the evaporator,the rotation angle relative to its central axis could be changed,thus changing the number and shape of the pores facing the vapor removal grooves.The wick deflection angle represented its change in spatial position relative to the fixed vapor removal grooves.The effect of the wick deflection angles on the heat transfer characteristics of the flat LHP was experimentally investigated.It was found that with the change of deflection angle,the number of pores in the evaporation-oriented zone would also change,which had a significant impact on the start-up process and heat transfer performance of LHP.When the deflection angle was 30°,LHP could start fastest at a low heat load of 20 W and operate stable at a high heat load of 180 W.
文摘t A series of inline pico hydropower systems,which could be used in confined space,especially for water distribution networks(WDNs),was designed and investigated.The turbine with an eye-shaped vertical water baffle was developed to evaluate the hydraulic performance.A three-dimensional dynamic mesh was employed and the inlet velocity was considered as the inlet boundary condition,whereas the outlet boundary was set as the outflow.Then,numerical simulations were conducted and the standard k-εturbulence model was found to be the best capable of predicting flow features through the comparison with the experimental results.The effects of the opening diameter of the water baffle and installation angle of the rotor on the flow field in the turbine were investigated.The results suggested that the water baffle opening at d=30 mm and the rotor at a 52°angle could achieve the highest efficiency of 5.93%.The proper eye-shaped baffle not only accelerates the fluid flow and generates positive hydrodynamic torque,but also eliminates the flow separation.The scheme proposed in this paper can be exploited for practical applications in the water pipelines at various conditions and power requirements.
