Cooled radial turbine for high power-to-weight applications

Okapuu, U.; Calvert, G.

doi:10.2514/3.44176

Cited by 3 publications

(1 citation statement)

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“…In the present study, the supercritical air is employed to reduce site area and increase the energy density of CAES system, 16 so the compressed air in the multistage radial turbine expands from supercritical to atmospheric conditions to obtain higher output power, which differs from the ordinary operating condition of radial turbines (Figure 1). [16][17][18][19][20][21][22][23] In addition, radial turbines, which are shrouded and unshrouded rotors with different blade profile, are all included in the multistage radial inflow turbine to meet the requirement of operation condition, thus it is difficult for the engineers to determine the stage that has higher flow loss to conduct performance improvement. Although some studies 24 has been conducted on the aerodynamic performance and internal flow patterns of multistage radial inflow turbine, the effects of supercritical condition and geometric parameters on the aerodynamic performance and flow characteristic of multistage radial turbine in CAES system is also still not revealed.…”

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Flow characteristic of a multistage radial turbine for supercritical compressed air energy storage system

Wang

Zhang

et al. 2017

Proceedings of the Institution of Mechanical Engineers, Part A:

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Compressed air in supercritical compressed air energy storage system expand from supercritical to atmospheric conditions at lower inlet temperature (<500 K) to generate MW scale power. Therefore, a new multistage radial turbine is adopted and the flow characteristic is investigated by numerical simulation. Effects of ideal gas model and tip clearance on the performance and flow field of the multistage turbine are revealed. Results show that ideal gas model can reveal flow pattern under supercritical condition correctly while leading to obvious deviation of isentropic enthalpy drop, entropy, and inlet-to-exit total temperature ratio. Relative differences for mass flow and efficiency are less than 2%, while the relative differences for output power reaches to 9.36%. For shrouded rotor, mixing of working fluid near hub, blade suction surface, and shroud is the main influencing factor of the flow loss in the rotor. For unshrouded rotor, leakage vortex promote mixture of the fluid deriving from the hub, shroud, and suction surface, and causes much higher flow loss in the channel of rotor. The rotors, which have higher blade height variation rate, present higher efficiency reduction when the tip clearance height is increased, which is because the proportion of tip clearance in blade inlet height increases with the increase of average aspect ratio, resulting in the increase of leakage flow at the leading edge of rotor blade. The pressure fluctuation near the tip clearance and efficiency reduction is also increased. The present study provides a reference for further design and optimization of the multistage radial turbines in compressed air energy storage.

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