Thermodynamic analysis of the rotary tooth compressor

Abstract

The Roots blower has no built-in compression and therefore is not efficient when it discharges gases at pressures substantially higher than at suction. The rotary tooth compressor, which includes built-in compression, has been proposed as a more efficient alternative. This paper describes an analytical study of the rotary tooth compressor. A mathematical model has been constructed to simulate the thermodynamic processes within it and hence predict its performance. The model allows for gas leakage as well as the main gas flow into and out of the working chamber. The estimated performance has been compared with experimental test results. The mathematical model was thereby validated. Further analyses were then carried out, using the validated mathematical model, to determine the magnitude of power and capacity losses in the machine. It is shown that the rotary tooth compressor is more efficient than the Roots blower at pressure ratios greater than about 1.4. Loss in capacity is most affected by gas leakage, and the main cause of loss in adiabatic efficiency is the power loss associated with high gas velocities during discharge.

Optimum Positioning of Ports in the Limaçon Gas Expanders

“…(0|Í+2TT) to repeat the procedure again over the 277 range of 0. This is iterated until the calculated error a falls within an acceptable range to reflect the cyclical nature of the thermodynamic process described, as suggested by Peng et al [24]. Once convergence has been achieved, the total energy fi^^p obtained from the expander in one cycle is calculated using numerical integration as follows:…”

Adding the Teaching of Claw Rotor Compressors to Fluid Machinery Courses

“…This mass fl ow continuously varies according to the pressure evolution of the fl uid in the chamber that is fi rstly pre-compressed and later delivered through the outlet port. Estimating V leak on the basis of an almost instantaneous process may be misleading, so use of a differential approach, such as the one outlined by Peng et al [14], seems to be more suitable. Nevertheless, building a mathematical model simulating all the thermodynamic processes inside a claw rotor compressor is beyond the scope of the current paper.…”

“…Expressions for the pumping speed and the power consumption were presented and predictions based on the model were compared with experimental data. An analytical study of the compressor is described in a more recent work [14], where the main gas fl ows entering and exiting the variable-volume chambers, taking gas leakage into account, are calculated to estimate power and capacity losses in the machine. Finally, studies on the profi le of the claw rotors have been presented [15].…”

Investigation of a novel circular arc claw rotor profile for claw vacuum pumps and its performance analysis

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