Effect of parameters affecting oil film formation on the top of a vane of a multiple vane type compressor was studied using a compressor with an electrical insulating circuit. Experiments were conducted with polyalkylene glycol by varying the cooling conditions. The extent of oil film formation was evaluated as the separation degree (SD) defined by the percentage of the contact potential to the applied voltage between vane and cylinder. In a cooling cycle, SD was higher in the suction period than in compression period. When the effect of operating conditions were examined, increase in suction superheat increased an average separation degree (ASD) probably because of viscosity enhancement of refrigerating oil through reduction of refrigerant gas solubility. Meanwhile, ASD increased with increasing rotational speed and decreasing discharge pressure. Such oil film behavior may be caused by pushing the vane against the cylinder, which is brought about by increasing the friction between the side of vane and the rotor groove. Finally, the wear test using a real gas heat pump system under the operating conditions corresponded to low ASD. As a result, the wear amount of the vane was significantly larger at lower rotational speeds and higher suction pressures.
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