Performance analysis of a novel oil-free rotary compressor

Abstract

A novel rotating piston-type compressor is presented. The conventional rolling piston architecture was redesigned to allow oil-free operation. The spring activated vane was replaced by a directly driven swinging vane to provide constant contact to the rotating piston. The model of the compressor was implemented in the AMESim simulation platform. Experiments were conducted on prototypes and the data were evaluated based on the simulation results. Directly unobservable geometric dimensions were estimated by adjusting the mathematical model parameters to the measured thermodynamic state variables with the use of a multi-parametric genetic algorithm. The simple genetic algorithm proved fast and adequate solutions. According to the collected results, the oil-free rotating piston architecture is significantly more sensitive to the sealing clearances compared to the conventional oil lubricated rolling piston compressors. Therefore, the theoretically estimated performance can only be achieved with extremely small manufacturing tolerances, which has to be maintained during the operation.

Application of morphed non-linear phase oscillators for representing rolling piston compressor performance

“…Unknown sealing clearance sizes due to material wear or inadequate precision at assembly are the usual cause of unpredictable operation. 3 Slight differences caused by the manufacturing or assembling can alter the behaviour of investigated appliance in a magnitude where the applied models would fail to resemble the studied parameters. Besides the alteration in geometry parameters, compressor performance can be improved by the application of additional oil injection into the compression chamber, 4 or by refrigerant vapour injection across the cylinder or the vane of rolling piston compressor.…”

“…(a) Schematic draw of a common rolling piston compressor. 3 (b) Pressurisation process within the rolling compressor cylinder.…”

“…Figure 1(a) represents the schematic of a common rolling piston compressor. 3 During the working cycle, the piston rotates in the clockwise direction and pressurizes the working fluid till it reaches the discharge pressure. When the discharge pressure is reached, the discharge valve opens and working fluid is released to the pressure tank across the discharge port.…”

“…Figure 1(b) is the illustration of a typical pressurization time diagram at given rotational speed of a rolling piston compressor extracted from model data. 3…”

Transient 3D CFD Simulation of a Stationary Vane, Oil Free, Rotary Compressor

“…In this design the vane is positioned by a pivoted beam similarly to the construction introduced by Jaworowski [11]. However, in this case the vane is actuated by a linkage mechanism which is directly driven by the crankshaft to keep constant clearance between the vane and the piston [24]. During the test period the initial prototype geometry was modified to improve the reliability and decrease the wiredrawing loss.…”