To investigate the vapor injection performance of a scroll compressor with a short profile

a three-dimensional transient numerical model of a vapor-injection scroll compressor for an electric vehicle with a displacement of 38 cm

3

/r is established and verified with deviations within 9.5%. We investigated the effects of the pressure and temperature of vapor injection on the performance of the scroll compressor using the model. The results show that under the condition of a constant superheat

with an increase in injection pressure

the discharge temperature of the compressor initially decreases and then gradually increases. Moreover

the heating capacity exhibits an increasing trend

with the maximum increase in heating capacity reaching 20.5% and 17.1% at rotary speeds of 5 000 and 6 000 r/min

respectively. In addition

the heating coefficient of performance (COP) increases during the first stage and then decreases. Moreover

the maximum values of the heating COP with vapor injection at the former speeds were 3.9% and 2.3% higher than those without vapor injection

respectively. The compressor efficiency exhibits the

same tendency as the heating COP

and the volumetric efficiency gradually decreases. The compressor discharge temperature increases slightly with constant injection pressure

whereas the compressor power

heating capacity

and heating COP remain almost constant as the injection temperature increases. Compared with the injection temperature

the injection pressure has a significant impact on the scroll compressor.