Abstract:

High turbine inlet temperatures can enhance turbine performance, but they often require additional cooling methods due to limitations in disk materials.However, the compact size and short blades of turbines used in underwater vehicles can hardly accommodate complex cooling channels.To address this issue, partial admission axial impulse turbines can utilize seawater as the cooling medium.An alternative way is jet impingement cooling. In this study, a three-dimensional computational fluid dynamics method is proposed to investigate the performance of partial admission axial impulse turbines with different injection mass flow rates and positions.The results show that the maximum temperature of the front and back disks decreases by 40.1% and 28.6%, respectively, and the maximum thermal stress of the disk decreases by 33.8% when the axial injection mass flow is 0.2kg/s.When 0.2kg/s axial water is injected with 0.1kg/s radial water, the maximum temperature of the front and back disks decreases by 46.2% and 33.8%, respectively, and the maximum thermal stress of the disk decreases by 36.7%.The efficiency of turbine and the temperature and thermal stress of the front and back disks are negatively correlated with the cooling water mass flow rate in the axial direction under the same radial water flow. These findings can provide insights into the jet impingement cooling strategy for partial admission axial impulse turbines.

Key words: partial admission axial turbines, underwater vehicle, fluid-thermal simulation, evaporation heat transfer, thermal stress, thermal deformation