Research on Energy Transport Characteristics of an Axial Flow Circulating Pump under Unpowered Driven and Pump Operating Conditions

An axial flow circulating pump (AFCP), as a key facility of the large vessel power system, is designed for conveying cooling water of the power system. The pump will be rotated actively under the drive of motor when the vessel is navigated at a low speed, which is called the pump operating condition (POC). Besides, it will be rotated passively under the drive of Inlet flow fluid energy in the case of the vessel at a high speed, which is called the unpowered driven condition (UDC). It is worth noting that the characteristics of internal flow, energy generation and dissipation laws of the AFCP are varied under UDC and POC. This paper analyzes the energy transfer laws of the AFCP under UDC and POC using the modified PANS model and energy conveying theory. Pressure propulsion power (accounting for 82.6%) is a primary factor affecting energy conveying, while Lamb vector divergence and enstrophy (accounting for 17.4%) have limited effects on energy conveying, according to the research findings. Moreover, more intense energy generation and dissipation can be found under UDC with a rising proportion between Lamb vector divergence and enstrophy.