分类: 能源科学 >> 储能技术 提交时间: 2024-03-31
摘要: This work experimentally explores the influence of thesodiumchloride pollution on thePEMFC performancein the marine saltsprayenvironment by analyzing the concentration diffusion characteristics of the sodium chloride in thePEMFC membraneelectrodes. Firstly, a set of experiments were carried out to determine the distribution of the sodium chloride components in the membrane electrodes, where five different salt spray environments (i.e., 100mg/L, 200mg/L, 300mg/L, 400mg/L, and 500mg/L of the salt component, respectively) were used/employed to analyze the concentration diffusion characteristics of the sodium chloride. Then, the obtained samples were microscopically characterized and elementally analyzed by thefield emission scanning electron microscopy(FESEM) and the energy spectrometry. Subsequently, a least squares-based model was proposed to predict the diffusion rate of the contaminatingions inthe membrane electrodes. Lastly, the pollution of the sodium chloride was evaluated/assessed to reveal theperformance degradationof the PEMFCs. The experimental results demonstrated that (1) the sodium chloride fraction existed as crystals orions inthe membrane electrodes in the marine salt spray environment; (2) the sodium chloride poisoning was founded in theproton exchange membranein the form ofsodium ions; (3) and the sodium-to-chloride ratio was proportional to the contamination time and the salt spray in the proton exchange membrane.
分类: 机械工程 >> 机械工程其他学科 提交时间: 2024-03-28
摘要: Increasing the transfer (HT) coefficient used in thermal industries is very important. Various methods are used to improve the efficiency of thermal heat HT so that maximum HT takes place in a smaller space. Ethylene glycol (EG) is generally used as an agent for convective HT. EG obtains energy from a hot source and discharges it to the required location. At present, the most consumption of EG is to produce engine cooling fluid. In the upcoming research, the TB of EG fluid in two-dimensional microchannels (MCs) has been investigated using molecular dynamics (MD) simulations, and the effect of variables such as MC dimensions and MC wall temperature (Temp) on the TB of the simulated fluid has been investigated. The results revealed that by increasing the Temp difference of the MC wall from 10 to 50 K, the maximum temperature (Max-Temp) and velocity (Max-Vel) of the target sample increased to 640.94 K and 0.024 Å/ps. It can be concluded that the increase in the cross-sectional area and the wall Temp difference leads to an increase in the HT rate in the MC.