Jinsheng Xiao

Thermal effect simulation of hydrogen cryo-adsorption storage system

One of the primary challenges to introduce hydrogen on the energy market is to improve onboard hydrogen storage and research more efficient distribution technologies to increase the amount of stored gas while lessening the storage pressure. The aim of this paper is to study hydrogen storage in an on-board hydrogen adsorption storage tank under low temperature and moderate pressures through the finite element analysis software Comsol MultiphysicsTM. The experimental study is carried out in a cylindrical tank with granular adsorbents in which the bed temperature is measured at various positions. The adsorbents we used in the experiment are activated carbon (NORIT R0.8) and metal-organic framework (Cu-BTC). Compared with the experiment results, the simulated pressure and temperature of the activated carbon (NORIT R0.8) have better agreement with experimental results than the metal-organic framework (Cu-BTC). The material properties of Cu-BTC are necessary to be identified accurately. Owing to the mass flow r...

Numerical study of thermal effects in cryo-adsorptive hydrogen storage tank

Hydrogen storage is an important issue in the practical application of hydrogen technology. Among various hydrogen storage technologies, the cryo-adsorptive hydrogen storage appears to have huge potential for a further research because of its high storage capacity at low pressure. In this study, a computational fluid dynamics model and a lumped parameter model are developed to simulate the cryo-adsorptive hydrogen storage processes. These two models are implemented on the fluentTM platform and matlab/simulinkTM environment, respectively. The thermodynamic behavior and thermal effect during the cryo-adsorptive hydrogen storage processes in a cryo-adsorption storage system are analyzed. Two adsorbents, activated carbon (Norit R0.8) and metal-organic-framework (Cu-BTC), have been studied. The pressure increases quickly at early stage and then keeps steady during the slow filling process. The temperature has larger gradient in the radial and smaller gradient in the axis. During the fast filling process, the r...

Structural optimization of two-stage thermoelectric generator for wide temperature range application

A 3-D finite element model of two-stage thermoelectric generator based on low-temperature thermoelectric material bismuth-telluride and medium-temperature thermoelectric material skutterudites is established. Based on the formal model, structural optimization of the two-stage thermoelectric generator is carried out. Results show that, reasonable design of the structure of two-stage thermoelectric generator can take full advantage of the characteristics of thermoelectric materials and effectively improve the performance of power generation. If contact resistance and all heat losses are neglected, the conversion efficiency of the two-stage thermoelectric generator can reach a value of 17.02%.

Fabrication and Characterization of Ceramic/Metal Composite Wear Preventive Coating

The air plasma spray (APS) technology was used to prepare WC/NiCrAl and WC/NiCrBSi ceramic/metal composite wear preventive coating on cast iron substrate. The microstructure, microhardness, bond strength and slurry wear preventive performance of coating was measured. The results revealed that all of the coating prepared by APS has good qualities. The coating with NiCrBSi as its combining metal is better than that with NiCrAl on wear preventive performance, and coating containing more WC is supreme than that containing less WC. Finally, wear mechanics and the principle of the coating’s wear preventive property was concluded.

Lower and Upper Bounds of Mechanical and Thermal Properties of Ceramic/Metal Composites

In this paper, the lower and upper bounds of Young’s modulus and Poisson ratio are determined by the effective stress method and effective strain method from material mechanics. The effective heat flux method based on the hypothesis of equivalent temperature difference and the effective temperature difference method based on the hypothesis of equivalent heat flux are proposed, the lower and upper bounds of the thermal conductivity of ceramic/metal composite material are determined similarly. The result shows that the property values of ceramic/metal composites calculated from current theoretical property formulas are within the lower and upper bounds determined by the above methods.

Reuse, Recycling and Recovery of End-of-Life New Energy Vehicles in China

China has the largest quantity of new energy vehicles (NEVs) in the world. As time progresses, a certain percentage of NEVs will enter the scrap stage every year. By examining the status quo and the problems of recycling of conventional end-of-life vehicles in China, this study investigated the potential market for end-of-life NEVs and existing problems in the recycling and reuse systems. It was found that the recycling and reuse systems’ needs should be considered ahead of time. Further, various modes and methods for the recycling and reuse of end-of-life NEVs and their parts were analysed. Several strategies for the recycling and reuse of NEVs are proposed, including the establishment of an independent industry model for the utilization of scrap NEV power batteries. This study provides a reference for establishing a sound recycling system for end-of-life NEVs and setting up a recycling and reuse platform for scrapped NEVs in China.

Modeling and Simulation of Ceramic/Metal Gradient Thermal Barrier Coating

Using the development tool C++ Builder and adopting object oriented programming method, the ceramic/metal gradient thermal barrier coating design software (CCDS) is developed according to software engineering criterion. The CCDS, which has user-friendly interface, is composed of three functional modules: preprocess module, analysis module and post process module. In addition, this software is attached with an optimal design module and an expert module. The calculation and design of the ceramic/metal gradient thermal barrier coating can be carried out by the CCDS, and the numerical results show good agreement with the analytical results.

Coupled Thermomechanical Analyses for Thermal Shock of Ceramic/Metal Gradient Thermal Barrier Coatings

A coupled and uncoupled non-linear thermomechanical finite element analysis using ANSYS have been carried out to analyze the heat transfer and associated thermal stresses during different simulated thermal shock processes, and the results of two analyses are discussed. It indicates that piezocaloric effect can be neglect when thermal shock intensity is mild and piezocaloric effect should be taken into account when thermal shock intensity is severe.

Fabrication and Characterization of Ceramic/Metal Gradient Thermal Barrier Coating

Four Coating schemes and two substrate materials are designed to evaluate the characteristics of the ceramic/metal gradient thermal barrier coating. The gradient coating is successfully prepared by plasma spray with single torch and single feeder. The coating performance is evaluated by observing microstructure, measuring thermal shock resistance and thermal residual stress. The coating microstructure is observed by scanning electron microscope (SEM). Diffractive peaks for the gradient coating are got at different zone by X-ray spectroscopy (XRS). The thermal shock experiment shows that the thermal shock resistance property of the gradient coating is better than that of the non-gradient coating. The measurements of thermal residual stresses in different coating schemes are carried out by hole-drilling method, the results show that compressional stress presents on 1Cr18Ni9Ti substrate and tensile stress presents on 2Cr13 substrate.

Thermal Shock Experiment and Simulation of Ceramic/Metal Gradient Thermal Barrier Coating

A thermal shock experiment is designed to explore the thermal shock properties of ceramic/metal gradient thermal barrier coating. The specimens are heated up by oxygen-acetylene flame and cooled by water spray. The experiment procedure includes two stages, heating the specimen from the initial temperature 30°C for 40s, and then cooling for 20s. The heat transfer and the associated thermal stresses produced during the thermal shock procedure are simulated by finite element method. Experimental results indicated that the specimen of gradient coating behaves better in thermal shock experiments, which agree with the results of simulation.