Effect of Nozzle Geometry on a Model Thermocompressor Performance – a Numerical Evaluation

Thermocompressors are widely used in a large number of industries that use steam as their heating medium or as a power generating utility. They are devices that use the energy of a high pressure fluid to move a low pressure fluid and enable it to be compressed to a higher pressure according to the principle of energyconversion. They work like a vacuum pump but without usage of any moving part and therefore they can saveenergy. The performance of a thermocompressor highly depends on its geometry especially its nozzle geometry. This paper aims to study the influence of nozzle geometry on the thermocompressor performance when it operates under the specified operating conditions. Several geometrical factors including nozzle throat diameter and nozzle exit plane diameter are considered for this investigation. The simulation is done by using the CFD software package, FLUENT. Since the flow is turbulent and supersonic, it will be an efficient tool to investigate the nozzle geometrical changes. The results indicate that the nozzle geometry can affect both the entrainment ratio and critical back pressure of the thermocompressor. This device uses water vapor as the working fluid. The motive pressure changes from 1.25 to 1.75 bar and the suction temperature is fixed at 30°C.

کلیدواژه ها:

Thermocompressor ، nozzle ، performance evaluation ، entrainment ratio ، CFD