Adsorbents are important components in adsorption refrigeration. The diameter of an adsorbent can affect the heat and mass transfer of an adsorber. The effect of particle diameter on effective thermal conductivity was...Adsorbents are important components in adsorption refrigeration. The diameter of an adsorbent can affect the heat and mass transfer of an adsorber. The effect of particle diameter on effective thermal conductivity was investigated. The heat transfer coefficient of the refrigerant and the void rate of the adsorbent layer can also affect the effective thermal conductivity of adsorbents. The performance of mass transfer in the adsorber is better when pressure drop decreases. Pressure drop decreases with increasing permeability. The permeability of the adsorbent layer can be improved with increasing adsorbent diameter. The effect of adsorbent diameter on refrigeration output power was experimentally studied. Output power initially increases and then decreases with increasing diameter under different cycle time conditions. Output power increases with decreasing cycle time under similar diameters.展开更多
A two-dimensional model for freezing and thawing phase change heat transfer in biological tissue embedded with two cryoprobes was established.In this model,the blood vessels were considered as tree-like branched fract...A two-dimensional model for freezing and thawing phase change heat transfer in biological tissue embedded with two cryoprobes was established.In this model,the blood vessels were considered as tree-like branched fractal network,and the effective flow rate and effective thermal conductivity of blood were obtained by fractal method.The temperature distribution and ice crystal growth process in biological tissue embedded with two cryoprobes during freezing-thawing process were numerically simulated.The results show that the growth velocity of ice crystal in freezing process from 200 to 400 s is more rapid than that from 400 to 600 s. Thawing process of frozen tissue occurs in the regions around cryoprobes tips and tissue boundary simultaneously,and the phase interfaces are close to each other until ice crystal melts completely.The distance of two cryoprobes has a more profound effect on the temperature distribution in freezing process at 400 s than at 800 s.展开更多
The influence of thermal circuit parameters on a buried underground cable is investigated using an ANFIS （adaptive neuro-fuzzy inference system）. Finite element solution of the heat conduction equation is used, comb...The influence of thermal circuit parameters on a buried underground cable is investigated using an ANFIS （adaptive neuro-fuzzy inference system）. Finite element solution of the heat conduction equation is used, combined with artificial intelligence methods. The cable temperature depends on several parameters, such as the ambient temperature, the currents flowing through the conductor and the resistivity of the surrounding soil. In this paper, ANFIS is used to simulate the problem of the thermal field of underground cables under various parameters variation and climatic conditions. The developed model was trained using data generated from FEM （finite element method） for different configurations （training set） of the thermal field problem. After training, the system is tested for several scenarios, differing significantly from the training cases. It is shown that the proposed method is very time efficient and accurate in calculating the thermal fields compared to the relatively time consuming finite element method; thus ANFIS provides a potential computationally efficient and inexpensive predictive tool for more effective thermal design of underground cable systems.展开更多
基金Supported by the Chinese Academy of Science Visiting Professorship for Senior International Scientists project(2009Z2-1973)
文摘Adsorbents are important components in adsorption refrigeration. The diameter of an adsorbent can affect the heat and mass transfer of an adsorber. The effect of particle diameter on effective thermal conductivity was investigated. The heat transfer coefficient of the refrigerant and the void rate of the adsorbent layer can also affect the effective thermal conductivity of adsorbents. The performance of mass transfer in the adsorber is better when pressure drop decreases. Pressure drop decreases with increasing permeability. The permeability of the adsorbent layer can be improved with increasing adsorbent diameter. The effect of adsorbent diameter on refrigeration output power was experimentally studied. Output power initially increases and then decreases with increasing diameter under different cycle time conditions. Output power increases with decreasing cycle time under similar diameters.
基金Project(50436030)supported by the National Natural Science Foundation of China
文摘A two-dimensional model for freezing and thawing phase change heat transfer in biological tissue embedded with two cryoprobes was established.In this model,the blood vessels were considered as tree-like branched fractal network,and the effective flow rate and effective thermal conductivity of blood were obtained by fractal method.The temperature distribution and ice crystal growth process in biological tissue embedded with two cryoprobes during freezing-thawing process were numerically simulated.The results show that the growth velocity of ice crystal in freezing process from 200 to 400 s is more rapid than that from 400 to 600 s. Thawing process of frozen tissue occurs in the regions around cryoprobes tips and tissue boundary simultaneously,and the phase interfaces are close to each other until ice crystal melts completely.The distance of two cryoprobes has a more profound effect on the temperature distribution in freezing process at 400 s than at 800 s.
文摘The influence of thermal circuit parameters on a buried underground cable is investigated using an ANFIS （adaptive neuro-fuzzy inference system）. Finite element solution of the heat conduction equation is used, combined with artificial intelligence methods. The cable temperature depends on several parameters, such as the ambient temperature, the currents flowing through the conductor and the resistivity of the surrounding soil. In this paper, ANFIS is used to simulate the problem of the thermal field of underground cables under various parameters variation and climatic conditions. The developed model was trained using data generated from FEM （finite element method） for different configurations （training set） of the thermal field problem. After training, the system is tested for several scenarios, differing significantly from the training cases. It is shown that the proposed method is very time efficient and accurate in calculating the thermal fields compared to the relatively time consuming finite element method; thus ANFIS provides a potential computationally efficient and inexpensive predictive tool for more effective thermal design of underground cable systems.
