Investigation of startup process for underwater turbine power systems using computational fluid dynamics method

The start-up process is vital to the performance of underwater turbine power system. The current analysis is mostly relied on analytical models established from simplified models and empirical formulas and it cannot accurately predict the start-up process. This paper proposes numerical methods to simulate the startup process of the underwater turbine power system. The results from the analytical and numerical models are compared at different launching depths. It is shown that the analytical model is suitable at the shallow launching depth (30 m), and the maximum difference is 4.3 % compared against the numerical method. However, the difference between analytical and numerical methods is as high as 45.9 % at the large launching depth (300 m). In addition, the closed-loop control strategy of the fuel pump needs to be triggered within 1.2 s after the combustion chamber is fully occupied, the start-up process can then be successful at the large launching depth. The experimental validation is finally performed to test the start-up process of the underwater turbine power system at the launching depths of 300 m.