在工业条件下实验研究一种新型“水包火”式辐射加热的传热功率和传热效率,分别在额定电功率为9,18,27,36,45 k W的条件下加热,使水温升高,用温度计测量水的温度变化,在炉膛内插入一支热电偶观察炉膛的温度变化。通过实验研究及理论计算...在工业条件下实验研究一种新型“水包火”式辐射加热的传热功率和传热效率,分别在额定电功率为9,18,27,36,45 k W的条件下加热,使水温升高,用温度计测量水的温度变化,在炉膛内插入一支热电偶观察炉膛的温度变化。通过实验研究及理论计算,论证了辐射传热对储能设备的传热效果,随着加热功率的增大,传热功率也增大,且二者呈正相关;传热效率则先增后减,且有一个明显的峰值。展开更多
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
In this work, laser heat conduction lap welding(LHCLW) of AZ31B magnesium alloy sheet and DP780galvanized steel sheet was carried out by the defocused laser beam. The effects of laser power on the microstructure and m...In this work, laser heat conduction lap welding(LHCLW) of AZ31B magnesium alloy sheet and DP780galvanized steel sheet was carried out by the defocused laser beam. The effects of laser power on the microstructure and mechanical properties of the joint were studied. The pros and cons of the joint were identified and evaluated by measuring the tensile shear strength, microhardness and microstructure observation. The formation mechanism of various phases at the Mg/steel interface was analyzed. The results indicated that the galvanized layer could promote the metallurgical bonding between magnesium alloy and steel by improving the diffusion ability of molten magnesium alloy at the steel interface and reacting with Mg, so as to enhance the strength of the joint. A continuous dense layered eutectic structure(α-Mg+MgZn) was formed at the interface of the joint, while MgZn_(2)and MgZn phase was formed at the weld edge zone and heat affective zone(HAZ), whereas no reaction layer was generated between the uncoated steel and magnesium alloy. A sound joint could be obtained at 2.5 kW, and the corresponding tensile shear strength reached the maximum value of 42.9 N/mm. The strength was slightly reduced at 2.6 kW due to the existence of microcracks in the eutectic reaction layer.展开更多
文摘在工业条件下实验研究一种新型“水包火”式辐射加热的传热功率和传热效率,分别在额定电功率为9,18,27,36,45 k W的条件下加热,使水温升高,用温度计测量水的温度变化,在炉膛内插入一支热电偶观察炉膛的温度变化。通过实验研究及理论计算,论证了辐射传热对储能设备的传热效果,随着加热功率的增大,传热功率也增大,且二者呈正相关;传热效率则先增后减,且有一个明显的峰值。
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Projects(51705219, 51905227) supported by the National Natural Science Foundation of ChinaProject(BK20200915) supported by the Natural Science Foundation of Jiangsu Province,ChinaProject(19KJB460013) supported by the General University Science Research Project of Jiangsu Province,China。
文摘In this work, laser heat conduction lap welding(LHCLW) of AZ31B magnesium alloy sheet and DP780galvanized steel sheet was carried out by the defocused laser beam. The effects of laser power on the microstructure and mechanical properties of the joint were studied. The pros and cons of the joint were identified and evaluated by measuring the tensile shear strength, microhardness and microstructure observation. The formation mechanism of various phases at the Mg/steel interface was analyzed. The results indicated that the galvanized layer could promote the metallurgical bonding between magnesium alloy and steel by improving the diffusion ability of molten magnesium alloy at the steel interface and reacting with Mg, so as to enhance the strength of the joint. A continuous dense layered eutectic structure(α-Mg+MgZn) was formed at the interface of the joint, while MgZn_(2)and MgZn phase was formed at the weld edge zone and heat affective zone(HAZ), whereas no reaction layer was generated between the uncoated steel and magnesium alloy. A sound joint could be obtained at 2.5 kW, and the corresponding tensile shear strength reached the maximum value of 42.9 N/mm. The strength was slightly reduced at 2.6 kW due to the existence of microcracks in the eutectic reaction layer.
