Experimental Study Of Two-Phase Flow In Anode Channels Of A Direct Methanol Fuel Cell Under Microgravity

Microgravity science, developing quickly with the development of the aerospace carrying person, is one of the front courses in the world nowadays. The gas-liquid two-phase flow under microgravity is one of the key technique problems in the space technique field and has important academic meaning and applied values.Fuel cell is a device that can continuously convert chemical energy of fuel and oxidant directly into electrical energy by the electrochemical reactions. Its application in the aerospace field has started get the value again because of its high specific power density, high specific energy density, speedy response, the characteristics of high power and longtime power supply.Under microgravity environment, the characteristic of two-phase flow in proton exchange membrane fuel cell is different from normal gravity environment. It is a new challenge for the management of gas and liquid in the fuel cells and becomes one of the key technique problems of proton exchange membrane fuel cell, resolved urgently.In this article, a transparent DMFC was designed and the experimental system was set up. With the aid of visualization technology, the two-phase flow with chemical reactions in the anode channels and the effect of the CO2 bubble on the cell performance were studied under normal and microgravity environment. The experimental results of two-phase flow and electric performance reveal the two-phase flow characteristics, the rule of bubble growing and breaking away and the effect of the gravity factor on cell performance. The work provided dependable scientific data and guidance for the application of the proton exchange membrane fuel cell in the aerospace realm.The main work and results of the study are presented as follows:1. An experimental test system for the direct methanol fuel cell under microgravity environment was set up. The visualization research platform was made up of the test system and the transparent DMFC as well as the drop tower. The system can perform the meansurement and collection of current and voltage of the fuel cell while observe the two-phase flow in fuel cell.2. A visual investigation of the effect of current density on the CO2 bubble behavior and the two-phase flow under normal and microgravity environment were carried out. The experimental results indicated that whether under normal or microgravity environment, the quantity and the size of CO2 bubble increase...