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
Single phases of ammonium penta and tetra molybdates were prepared. The massic heat capacities at normal pre ssure below their decomposition temperatures were measured by drop method. The relationships of the massic h...Single phases of ammonium penta and tetra molybdates were prepared. The massic heat capacities at normal pre ssure below their decomposition temperatures were measured by drop method. The relationships of the massic heat capacities of ammonium molybdates with those of the decomposition products were also discussed. The results show that the massic heat capacities of ammonium molybdates can be estimated by adding together contributions from their decomposition products, and the less change of chemical bonds, the more accurate of the estimation.展开更多
The thermal behavior,non-isothermal thermal decomposition reaction kinetics and specific heat capacity of hexanitro-hexaazaisowurtzitane(HNIW)were studied by differential scanning calorimeter(DSC)and Micro-DSCIapparat...The thermal behavior,non-isothermal thermal decomposition reaction kinetics and specific heat capacity of hexanitro-hexaazaisowurtzitane(HNIW)were studied by differential scanning calorimeter(DSC)and Micro-DSCIapparatus,The kinetic parameters of the thermal decomposition reaction(the apparent activation energy(E,)and pre-exponential factor(A))were calcu-lated by non-isothermal DSC curves.The results show that the differential mlechanism function and values of E,and A of the ther-mal decomposition reaction of HNIW are 3(1-a)[-ln(1-a)]"·,155.04 kJ·mol^(-1)and 10""s^(-1),respectively.The critical tem-perature of thermal explosion of the title compound is 226.60℃.The entropy of activation(AS·),enthalpy of activation(AH·)and free energy of activation(AG·)of this reaction are 11.60J·mol·K^(-1),152.04 kJ·mol^(-1)and 146.29 kJ·mol^(-1),respec-tively.The equation of specific heat capacity of HNIW with temperature is C,=0.2472+0.002705992Tin the temperature range of 283 K to 343K.The values of self-accelerating decomposition temperature,adiabatic time-to-maximum decomposition rate and adiabatic time-to-explosion are 486.5K,54.81s and 54.31s,respectively.Thermal sensitivity probability density distribution curve of HNIW is constructed.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.
文摘Single phases of ammonium penta and tetra molybdates were prepared. The massic heat capacities at normal pre ssure below their decomposition temperatures were measured by drop method. The relationships of the massic heat capacities of ammonium molybdates with those of the decomposition products were also discussed. The results show that the massic heat capacities of ammonium molybdates can be estimated by adding together contributions from their decomposition products, and the less change of chemical bonds, the more accurate of the estimation.
基金The National Nature Science Foundation of China(21173163)
文摘The thermal behavior,non-isothermal thermal decomposition reaction kinetics and specific heat capacity of hexanitro-hexaazaisowurtzitane(HNIW)were studied by differential scanning calorimeter(DSC)and Micro-DSCIapparatus,The kinetic parameters of the thermal decomposition reaction(the apparent activation energy(E,)and pre-exponential factor(A))were calcu-lated by non-isothermal DSC curves.The results show that the differential mlechanism function and values of E,and A of the ther-mal decomposition reaction of HNIW are 3(1-a)[-ln(1-a)]"·,155.04 kJ·mol^(-1)and 10""s^(-1),respectively.The critical tem-perature of thermal explosion of the title compound is 226.60℃.The entropy of activation(AS·),enthalpy of activation(AH·)and free energy of activation(AG·)of this reaction are 11.60J·mol·K^(-1),152.04 kJ·mol^(-1)and 146.29 kJ·mol^(-1),respec-tively.The equation of specific heat capacity of HNIW with temperature is C,=0.2472+0.002705992Tin the temperature range of 283 K to 343K.The values of self-accelerating decomposition temperature,adiabatic time-to-maximum decomposition rate and adiabatic time-to-explosion are 486.5K,54.81s and 54.31s,respectively.Thermal sensitivity probability density distribution curve of HNIW is constructed.
