A particle sub-model describing the bed characteristics of a bubbling fluidised bed is presented. Atomisation air, applied at high pressures via a nozzle positioned above the bed for spray formation, is incorporated i...A particle sub-model describing the bed characteristics of a bubbling fluidised bed is presented. Atomisation air, applied at high pressures via a nozzle positioned above the bed for spray formation, is incorporated in the model since its presence has a profound influence on the bed characteristics, though the spray itself is not yet considered. A particle sub-model is developed using well-known empirical relations for particle drag force, bubble growth and velocity and particle distribution above the fluidised-bed surface. Simple but effective assumptions and abstractions were made concerning bubble distribution, particle ejection at the bed surface and the behaviour of atomisation air flow upon impacting the surface of a bubbling fluidised bed, The model was shown to be capable of predicting the fluidised bed characteristics in terms of bed heights, voidage distributions and solids volume fractions with good accuracy in less than 5 min of calculation time on a regular desktop PC. It is therefore suitable for incorporation into general process control models aimed at dynamic control for process efficiency and product quality in top-spray fluidised bed coating processes.展开更多
This study focuses on the heat transfer characteristics of the evaporation terminal,the cool distribute unit(CDU)and refrigerant flow distribution of a water cooled multi-spilit heat pipe system(MSHPS)used in data cen...This study focuses on the heat transfer characteristics of the evaporation terminal,the cool distribute unit(CDU)and refrigerant flow distribution of a water cooled multi-spilit heat pipe system(MSHPS)used in data center.The finite time thermodynamic analysis,the exergy method and the software SIMULINK was employed to build the simulation model of the combined system.The results show that the IT servers should concentrate on arranging at the location below 1.3 m.The CDU has a heat transfer of about 74 J in a period of 6 s.And the optimum flow rate of the CDU is 0.82 kg/s.The flow distribution characteristic of a CDU which connect 2 heat pipe evaporator terminals of 6 kW was calculated,and the working fluid is R22.Then the free cooling time,part time free cooling and energy saving potential in major cities of China were analysised.The energy saving potential is from 61%to 25%.The results are of great significance for the operational control and practical application of a MSHPS and other pipe-net systems.展开更多
基金the financial support of the Special Research Fund (BOF) of the Ghent University
文摘A particle sub-model describing the bed characteristics of a bubbling fluidised bed is presented. Atomisation air, applied at high pressures via a nozzle positioned above the bed for spray formation, is incorporated in the model since its presence has a profound influence on the bed characteristics, though the spray itself is not yet considered. A particle sub-model is developed using well-known empirical relations for particle drag force, bubble growth and velocity and particle distribution above the fluidised-bed surface. Simple but effective assumptions and abstractions were made concerning bubble distribution, particle ejection at the bed surface and the behaviour of atomisation air flow upon impacting the surface of a bubbling fluidised bed, The model was shown to be capable of predicting the fluidised bed characteristics in terms of bed heights, voidage distributions and solids volume fractions with good accuracy in less than 5 min of calculation time on a regular desktop PC. It is therefore suitable for incorporation into general process control models aimed at dynamic control for process efficiency and product quality in top-spray fluidised bed coating processes.
基金Thanks for the support of Hunan postdoctoral fund(Number:198514)。
文摘This study focuses on the heat transfer characteristics of the evaporation terminal,the cool distribute unit(CDU)and refrigerant flow distribution of a water cooled multi-spilit heat pipe system(MSHPS)used in data center.The finite time thermodynamic analysis,the exergy method and the software SIMULINK was employed to build the simulation model of the combined system.The results show that the IT servers should concentrate on arranging at the location below 1.3 m.The CDU has a heat transfer of about 74 J in a period of 6 s.And the optimum flow rate of the CDU is 0.82 kg/s.The flow distribution characteristic of a CDU which connect 2 heat pipe evaporator terminals of 6 kW was calculated,and the working fluid is R22.Then the free cooling time,part time free cooling and energy saving potential in major cities of China were analysised.The energy saving potential is from 61%to 25%.The results are of great significance for the operational control and practical application of a MSHPS and other pipe-net systems.
