Analytical and experimental study of a self-rectifying turbine driven by a liquid piston stirling engine

We aim to develop a low-cost, long-life power generator by combining a Liquid Piston Stirling Engine (LPSE) with a self-rectifying turbine. In this system, the self-rectifying turbine is installed in the liquid column section of the LPSE and is driven by the longitudinal oscillations of the water column. These oscillations result from the thermoacoustic energy conversion performed by the LPSE, and the turbine extracts shaft power from this motion. Our previous studies have shown that the flow resistance in the pipe section, where the turbine is mounted is a key parameter for maximizing the power transferred to the self-rectifying turbine. However, the relationship between this flow resistance and the turbine’s design, as well as the characteristics of the oscillatory water flow, remains poorly understood. As a result, no clear guidelines for optimal design have been established. This study investigates an analytical method for estimating both the flow resistance and efficiency of the turbine. Focusing on turbines with known torque and input coefficients, we analytically solve the rotational equation of motion under harmonically oscillating flow. The validity of these results will be verified through comparison with experimental data.