Study on pressurization characteristics of single-screw steam compressor with water spray cooling under fluctuating heat source operating conditions

For a water-injected single-screw steam compressor (SSSC), the performance of the compressor is significantly affected by the water spray rate. However, the precise relationship between the water injection parameters and the operating parameters of the heat source under fluctuating heat source operating conditions (FHSOC) has not been elucidated. This paper introduces a constructed thermodynamic analysis model for the wet compression process under FHSOC aiming to explore the impact of fluctuating heat source parameters such as inlet steam temperature (IST) and inlet steam dryness (ISD) on the thermodynamic performance parameters of the compressor. The operational performance of the SSSC is then analyzed and compared under two distinct conditions: optimal water spray rate (OWSR) and fixed water spray rate (FWSR). The results demonstrate that when the IST of the SSSC increases within the range of 375 K-400 K, there is an initial decline followed by an increase in both the leakage rate and volumetric efficiency. Simultaneously, displacement and power consumption decrease, while adiabatic indicated efficiency and OWSR increase. Within this range, an optimal synergy is observed between IST and water spray parameters enabling the compressor to exhibit superior lubrication, sealing, and pressurization performance. On the other hand, when the ISD increases within the range of 0.92-1, the total heat transfer in the compression chamber decreases, and the leakage, OWSR, displacement, power consumption, adiabatic indicated efficiency, and volumetric efficiency all show varying degrees of increase. Regarding the volumetric efficiency corresponding to the OWSR, the impact of ISD on volumetric efficiency surpasses that of IST to a significant degree.