Experimental investigation on water injected twin screw compressor for fuel cell humidification

A water injection in Twin Screw compressors was examined in order to develop effective humidification and cooling schemes for fuel cell stacks as well as cooling for compressors. The temperature and the relative humidity of the air at suction and exhaust of the compressor were monitored under constant pressure and water injection rate and at variable compressor’s operating speeds. The experimental results showed that the relative humidity of the outlet air was increased by the water injection. The injection tends to have more effect on humidity at low operating speeds/ mass flow rates. Further humidification can be achieved at higher speeds as higher evaporation rate becomes available. It was also found that the rate of power produced by the fuel cell stack was higher than the rate used to run the compressor for the same amount of air supplied. The efficiency of the Balance-Of-Plant (BOP) was therefore higher when more air is delivered to the stack. However, this increase in the air supply needs additional subsystems for further humidification/ cooling of the BOP system

A Numerical and Experimental Investigation of Pulsation Induced Noise in Screw Compressors

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Some Aspects of Estimating Geometric Characteristics of Screw Compressors

The methods used today for the calculation of screw compressor thermodynamic and fluid flow processes, from quasi one-dimensional thermodynamic models to three-dimensional computational fluid dynamics (CFD) procedures, require accurate identification and quantification of geometric parameters, such as volume, gradient and cross-section, leakage flow and blow-hole areas. Historically, some of the geometric characteristics have been neglected, or approximated when calculation accuracy was not essential. However, more sophisticated models may lose some of their advantages if accurate geometric characteristics are not included in them. The work presented in this paper is aimed to enhance the accuracy of geometric calculations. The usual geometric calculation procedures are given and modified where necessary. The results are compared with models generated by 3D Computer Aided Design (CAD), software packages, from which improvements in the accuracy of predictions can be demonstrated