The shrouded radial-inflow turbine is widely employed as a power generation device in the compressed air energy storage (CAES) system. The loss mechanism and off-designed performance of the shrouded radial turbine are lesser known hitherto and should be deeply understood. Loss analyses of a shrouded radial turbine are conducted numerically based on the first and second laws of thermodynamics in the current study. The relationship between losses and the secondary flow has been discussed in detail. A high proportion of loss in the rotor and outblock passage is found under off-designed conditions. The secondary vortex cores and wake are the primary sources of energy dissipation, while the entropy generation mainly appears at the edge of secondary vortices. The suction-surface separation expands as the velocity ratio is decreased, making the high entropy generation scope on the cross-sectional plane wider. Reducing the seal clearance and avoiding the low velocity ratio conditions are quite necessary to reduce losses. It is recommended the outlet passage should be designed longer than the length of rotor axial chord for a uniform outflow.
VenkataramaniGParankusamPRamalingamV, et al.
A review on compressed air energy storage – a pathway for smart grid and polygeneration. Renew Sust Energ Rev2016;
62: 895–907.
2.
ZhangYXuYZhouX, et al.
Compressed air energy storage system with variable configuration for accommodating large-amplitude wind power fluctuation. Appl Energy2019;
239: 957–968.
3.
LiHZhangXLiW, et al.
Experimental investigation of a liquid turbine in a full performance test rig. Proc IMechE, Part A: J Power and Energy2019;
233: 337–345.
4.
WangXLiWZhangX, et al.
Flow characteristic of a multistage radial turbine for supercritical compressed air energy storage system. Proc IMechE, Part A: J Power and Energy2018;
232: 622–640.
5.
HePSunZGuoB, et al.
Aerothermal investigation of backface clearance flow in deeply scalloped radial turbines. J Turbomach2013;
135: 021002.
6.
DentonJD.Loss mechanisms in turbomachines. J Turbomach1993;
115: 621–656.
7.
DambachRHodsonHPHuntsmanI.An experimental study of tip clearance flow in a radial inflow turbine. J Turbomach1999;
121: 644–650.
8.
DengQHNiuJFFengZP.Study on leakage flow characteristics of radial inflow turbines at rotor tip clearance. Sci China Ser E-Technol Sci2008;
51: 1125–1136.
9.
SerranoJRNavarroRGarcía-CuevasLM, et al.
Turbocharger turbine rotor tip leakage loss and mass flow model valid up to extreme off-design conditions with high blade to jet speed ratio. Energy2018;
147: 1299–1310.
10.
WangXLiWZhangX, et al.
Efficiency improvement of a CAES low aspect ratio radial inflow turbine by NACA blade profile. Renew Energy2019;
138: 1214–1231.
11.
DuYChenHHaoM, et al.
Off-design performance comparative analysis of a transcritical CO 2 power cycle using a radial turbine by different operation methods. Energy Convers Manage2018;
168: 529–544.
12.
RogoC. Variable area radial turbine fabrication and test program. NASA Report. No. NASA-CR-175091, 1986.
13.
SimonyiPSBoyleRJ. Comparison of a quasi-3D analysis and experimental performance for three compact radial turbines. AIAA Report. No. AIAA-91-2128, 1991.
14.
SimonyiPSRoelkeRJStabeRG. Aerodynamic evaluation of two compact radial-inflow turbine rotors. NASA Report. No. NASA TP-3514, 1995.
15.
MarechaleRJiMCaveM. Experimental and numerical investigation of labyrinth seal clearance impact on centrifugal impeller performance. ASME Paper No. GT2015-43778, 2015.
16.
VanniniGBertoneriMNielsenKK, et al.
Experimental results and computational fluid dynamics simulations of labyrinth and pocket damper seals for wet gas compression. J Eng Gas Turbines Power2015;
138: 052501.
17.
DalbertPRibiBKmeciT, et al.
Radial compressor design for industrial compressor. Proc IMechE, Part C: J Mechanical Engineering Science1999;
213: 71–83.
18.
MischoBRibiBSeebass-LinggiC, et al. Influence of labyrinth seal leakage on centrifugal compressor performance. ASME Paper. No. GT2009-59524, 2009.
19.
RibaudY. Experimental Aerodynamic analysis relative to three high pressure ratio centrifugal compressors. ASME Paper. No. 87-GT-153, 1987.
YanXLiJFengZ.Effects of inlet preswirl and cell diameter and depth on honeycomb seal characteristics. J Eng Gas Turbines Power2010;
132: 122506.
22.
LiWWangXZhangXH, et al.
Experimental and numerical investigation of closed radial-inflow turbine with labyrinth seals. J Eng Gas Turbines Power2018;
140: 102502.
23.
ICEM-CFD 15.0 theory guide. Canonsburg: ANSYS Inc., 2013.
AinleyDGMathiesonGCR. A method of performance estimation for axial-flow turbines. Aeronautical Research Council Technical Report R&M. No. 2974, 1951.
26.
DixonSLHallC.Fluid mechanics and thermodynamics of turbomachinery.
Oxford:
Butterworth Heinemann, 2010.
27.
ZhangLZhuHRLiuCL, et al. Experimental and numerical investigation on leakage characteristic of stepped labyrinth seal. ASME Paper. No. GT2016-56743, 2016.
28.
BejanA.Entropy generation through heat and fluid flow.
Hoboken:
Wiley, 1982.
29.
ZlatinovMBSooi TanCMontgomeryM, et al.
Turbine hub and shroud sealing flow loss mechanisms. J Turbomach2012;
134: 061027.
30.
ErogluHTabakoffW. LDV measurements of turbulent stresses in radial turbine guide vanes. ASME Paper. No. 90-GT-75, 1990.
31.
HashemiSGRLemakRJOwczarekJA.An investigation of the flow characteristics and of losses in radial nozzle cascades. J Eng Gas Turbines Power1984;
106: 502–509.
32.
PutraMAJoosF.Investigation of secondary flow behavior in a radial turbine nozzle. J Turbomach2013;
135: 061003.
33.
NatkaniecCKKammeyerJSeumeJR. Secondary flow structures and losses in a radial turbine nozzle. ASME Paper. No. GT2011-46753, 2011.
34.
SimpsonATSpenceSWTWattersonJK.A comparison of the flow structures and losses within vaned and vaneless stators for radial turbines. J Turbomach2009;
131: 031010.
35.
DentonJD. Some limitations of turbomachinery CFD. ASME Paper. No. GT2010-22540, 2010.
36.
ShaoZLiWWangX, et al.
Analysis of shroud cavity leakage in a radial turbine for optimal operation in compressed air energy storage system. J Eng Gas Turbines Power2020;
142: 071005.
37.
LiuYZhangT-LZhangM, et al.
Numerical and experimental investigation of aerodynamic performance for a straight turbine Cascade with a novel partial shroud. J Fluids Eng2015;
138: 031206.
38.
PopovićI, andHodsonHP. Aerothermal impact of the interaction between hub leakage and mainstream flows in highly-loaded HP turbine blades. ASME Paper. No. GT2010-22311, 2010.
39.
SchulerPKurzWDullenkopfK, et al. The influence of different rim seal geometries on hot-gas ingestion and total pressure loss in a low-pressure turbine. ASME Paper. No. GT2010-22205, 2010.
40.
OngJHPMillerRJUchidaS. The effect of coolant injection on the endwall flow of a high pressure turbine. ASME Paper. No. GT2006-91060, 2006.
41.
PaniaguaGDéNosRAlmeidaS.Effect of the hub endwall cavity flow on the flow-field of a transonic high-pressure turbine. J Turbomach2004;
126: 578–586.
