A comprehensive mathematical model is proposed to study the transport phenomena in an Electrodialysis (ED) process employed to recover lithium hydroxide and sulfuric acid from the lithium sulphate solution derived from a recycling process of spent lithium-ion battery material. The model is developed based on the conservation equations of mass and ions, and considers electrolyte solutions consisting of mono- and multivalence ions. The concentration polarization at ion exchanged membranes (IEMs) and their adjacent diffusion boundary layers as a function of the applied current, inlet concentrations and flow rate are computed. Experimental data from a three-compartment ED cell are used for validation. A parametric study is performed to evaluate the impact of parameters on transmembrane fluxes of ion and water. It is revealed that increasing current leads to the enhancement of the transmembrane water and concentration polarization across IEMs. Feeding solutions consisting of smaller ions result in lower water transfer through IEMs. Raising the lithium concentration at the dilute channel increases the LiOH concentration due to reduced transmembrane water transfer. Using the uncertainty propagation method, it is found that current and counter-ion radius are the most influential parameters affecting the outlet concentration of concentrate channel and transmembrane water transfer.

Latent thermal energy storage is regarded as an effective strategy to utilize solar energy and recover automotive waste heat. Based upon an enthalpy-porosity method, the influence characteristics and mechanism of fin location on phase change material melting behavior in vertical rectangular enclosures were explored numerically. The results show that as fin location increases, the melting time decreases before attaining the minimum at the fin location of 0.20 after which it increases and finally surpasses the no fin case, because (1) the influence range of fins for conduction is limited by the bottom surface when putting fins next to this surface, (2) the liquid flow resistance increases with moving fins up, and (3) mounting fins near the top surface accelerates melting at the upper part, facilitating thermal stratification formation and weakening natural convection. Nu is higher than the no fin case, i.e., Nu enhancement factor is a positive value, in the melting process for a lower fin location, while for other fin locations, a transition to a negative value takes place. The higher the fin location is, the earlier the transition that arises. Finally, a strategy of increasing the maximum liquid flow velocity is proposed to reinforce melting for cases with considerable natural convection.

An experimental study using electrical heating method has been performed to explore the impact of wind speed, wind incidence angle as well as cavity inclination on the heat losses from a fully open cylindrical cavity with only bottom wall heated at constant heat flux. The cavity under different inclinations is subjected to four different wind speeds of 1.15, 1.84, 2.94, 5.69 m/s, and wind incidence angles from 0° (wind blowing parallel to cavity aperture plane) to 90° (wind blowing vertically to cavity aperture plane) at intervals of 30°. Results reveal that, the average temperature of cavity wall decreases with increasing wind speed and wind incidence angle. The combined convection heat loss increases obviously with the increase of wind speed, while the radiation and conduction heat losses decrease for all wind incidence angles. The variations of convection heat loss with the cavity inclination at constant heat flux boundary condition are quite different from that at constant wall temperature boundary condition. The combined free-forced convection heat loss Nusselt number Nu_c is more sensitive to the wind speed and wind incidence angle in comparison with the radiation heat loss Nusselt number Nu_r. In addition, new correlations of Nusselt numbers have been developed to estimate the convection heat loss and radiation heat loss due to the environmental wind.