On the basis of thermoelastic theory, a thermoelastic equivalent circuit model for laser-generated ultrasound has been proposed. With this model, laser-heated region is des cribed as a three-port electrical circuit wh...On the basis of thermoelastic theory, a thermoelastic equivalent circuit model for laser-generated ultrasound has been proposed. With this model, laser-heated region is des cribed as a three-port electrical circuit which interprets the direct conversion bctween thermal energy and elastic energy. As the circuit is derived from single frequency excitation, arbitrary temporal response can be calculated by means of IFFT algorithm. In this paper, three kinds of ideal heated regions are considered which arc circular plate, cylinder and sphere, the corre spondent one-dimensional adiabatic thermoelastic equivalent circuits are completed, and their pressure responses are calculated. It is shown that the results agree well with previous reports.展开更多
短路电流容量计算的基本原理尽管在OPGW相关的标准中有过叙述,但很少有实际计算方法上的报道。文章编译自古河电工提交给国际大电网协会C IGRE SC22 WG12 2002年巴黎会议的最终草案,对OPGW的特定参数进行了简要介绍,详细阐述了短路电流...短路电流容量计算的基本原理尽管在OPGW相关的标准中有过叙述,但很少有实际计算方法上的报道。文章编译自古河电工提交给国际大电网协会C IGRE SC22 WG12 2002年巴黎会议的最终草案,对OPGW的特定参数进行了简要介绍,详细阐述了短路电流容量的计算原理以及与实测结果的对照。展开更多
Because of the high cost of measuring the specific heat capacity and the difficulty in measuring the thermal conductivity of prismatic lithium-ion batteries,two devices with a sandwiched core of the sample-electric he...Because of the high cost of measuring the specific heat capacity and the difficulty in measuring the thermal conductivity of prismatic lithium-ion batteries,two devices with a sandwiched core of the sample-electric heating film-sample were designed and developed to measure the thermal properties of the batteries based on Fourier's thermal equation.Similar to electrical circuit modeling,two equivalent thermal circuits were constructed to model the heat loss of the self-made devices,one thermal-resistance steady circuit for the purpose of measuring the thermal conductivity,the other thermal-resistance-capacitance dynamic circuit for the purpose of measuring the specific heat capacity.Using the analytic method and recursive least squares,the lumped model parameters of these two thermal circuits were extracted to estimate the heat loss and correct the measured values of the self-made devices.Compared to the standard values of the reference samples of the glass and steel plates,the measured values were corrected to improve the measurement accuracies beyond 95% through steady thermal-circuit modeling.Compared to the measured value of the specific heat capacity of the battery sample at 50% state of charge using the calorimeter,the measured value using the self-made device was corrected in order to elevate the measurement accuracy by about 90% through dynamic thermal-circuit modeling.As verified through the experiments,it was reliable,convenient,and low cost for the proposed methodology to measure the thermal properties of prismatic lithium-ion batteries.展开更多
文摘On the basis of thermoelastic theory, a thermoelastic equivalent circuit model for laser-generated ultrasound has been proposed. With this model, laser-heated region is des cribed as a three-port electrical circuit which interprets the direct conversion bctween thermal energy and elastic energy. As the circuit is derived from single frequency excitation, arbitrary temporal response can be calculated by means of IFFT algorithm. In this paper, three kinds of ideal heated regions are considered which arc circular plate, cylinder and sphere, the corre spondent one-dimensional adiabatic thermoelastic equivalent circuits are completed, and their pressure responses are calculated. It is shown that the results agree well with previous reports.
基金This work was supported by the National Key R&D Program of China(No.2018YFBO106104)the National Natural Science Foundation of China(No.51677006).
文摘Because of the high cost of measuring the specific heat capacity and the difficulty in measuring the thermal conductivity of prismatic lithium-ion batteries,two devices with a sandwiched core of the sample-electric heating film-sample were designed and developed to measure the thermal properties of the batteries based on Fourier's thermal equation.Similar to electrical circuit modeling,two equivalent thermal circuits were constructed to model the heat loss of the self-made devices,one thermal-resistance steady circuit for the purpose of measuring the thermal conductivity,the other thermal-resistance-capacitance dynamic circuit for the purpose of measuring the specific heat capacity.Using the analytic method and recursive least squares,the lumped model parameters of these two thermal circuits were extracted to estimate the heat loss and correct the measured values of the self-made devices.Compared to the standard values of the reference samples of the glass and steel plates,the measured values were corrected to improve the measurement accuracies beyond 95% through steady thermal-circuit modeling.Compared to the measured value of the specific heat capacity of the battery sample at 50% state of charge using the calorimeter,the measured value using the self-made device was corrected in order to elevate the measurement accuracy by about 90% through dynamic thermal-circuit modeling.As verified through the experiments,it was reliable,convenient,and low cost for the proposed methodology to measure the thermal properties of prismatic lithium-ion batteries.
