{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,8]],"date-time":"2026-06-08T01:51:22Z","timestamp":1780883482460,"version":"3.54.1"},"reference-count":34,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2023,2,12]],"date-time":"2023-02-12T00:00:00Z","timestamp":1676160000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Natural Science Foundation of China","award":["51675254"],"award-info":[{"award-number":["51675254"]}]},{"name":"National Natural Science Foundation of China","award":["51966009"],"award-info":[{"award-number":["51966009"]}]},{"name":"National Natural Science Foundation of China","award":["SQ2020YFF0420989"],"award-info":[{"award-number":["SQ2020YFF0420989"]}]},{"name":"National Natural Science Foundation of China","award":["2020-RC-23"],"award-info":[{"award-number":["2020-RC-23"]}]},{"name":"National Natural Science Foundation of China","award":["20YF8GA057"],"award-info":[{"award-number":["20YF8GA057"]}]},{"name":"National Key Research and Development Program of China","award":["51675254"],"award-info":[{"award-number":["51675254"]}]},{"name":"National Key Research and Development Program of China","award":["51966009"],"award-info":[{"award-number":["51966009"]}]},{"name":"National Key Research and Development Program of China","award":["SQ2020YFF0420989"],"award-info":[{"award-number":["SQ2020YFF0420989"]}]},{"name":"National Key Research and Development Program of China","award":["2020-RC-23"],"award-info":[{"award-number":["2020-RC-23"]}]},{"name":"National Key Research and Development Program of China","award":["20YF8GA057"],"award-info":[{"award-number":["20YF8GA057"]}]},{"name":"Talent Innovation and Entrepreneurship Program of Lanzhou","award":["51675254"],"award-info":[{"award-number":["51675254"]}]},{"name":"Talent Innovation and Entrepreneurship Program of Lanzhou","award":["51966009"],"award-info":[{"award-number":["51966009"]}]},{"name":"Talent Innovation and Entrepreneurship Program of Lanzhou","award":["SQ2020YFF0420989"],"award-info":[{"award-number":["SQ2020YFF0420989"]}]},{"name":"Talent Innovation and Entrepreneurship Program of Lanzhou","award":["2020-RC-23"],"award-info":[{"award-number":["2020-RC-23"]}]},{"name":"Talent Innovation and Entrepreneurship Program of Lanzhou","award":["20YF8GA057"],"award-info":[{"award-number":["20YF8GA057"]}]},{"name":"Science and Technology Program of Gansu Province","award":["51675254"],"award-info":[{"award-number":["51675254"]}]},{"name":"Science and Technology Program of Gansu Province","award":["51966009"],"award-info":[{"award-number":["51966009"]}]},{"name":"Science and Technology Program of Gansu Province","award":["SQ2020YFF0420989"],"award-info":[{"award-number":["SQ2020YFF0420989"]}]},{"name":"Science and Technology Program of Gansu Province","award":["2020-RC-23"],"award-info":[{"award-number":["2020-RC-23"]}]},{"name":"Science and Technology Program of Gansu Province","award":["20YF8GA057"],"award-info":[{"award-number":["20YF8GA057"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Entropy"],"abstract":"<jats:p>Tangential leakage loss is the primary factor that significantly affects the output performance of oil-free scroll expanders. A scroll expander can function under different operating conditions, and the flow of tangential leakage and generation mechanism is different. This study employed computational fluid dynamics to investigate the unsteady flow characteristics of the tangential leakage flow of a scroll expander with air as the working fluid. Consequently, the effects of different radial gap sizes, rotational speeds, inlet pressures, and temperatures on the tangential leakage were discussed. The tangential leakage decreased with increases in the scroll expander rotational speed, inlet pressure, and temperature, and decreased with decrease in radial clearance. With an equal-proportional increase in radial clearance, the flow form of the gas in the first expansion and back-pressure chambers became more complicated; when the radial clearance increased from 0.2 to 0.5 mm, the volumetric efficiency of the scroll expander decreased by approximately 5.0521%. Moreover, because of the large radial clearance, the tangential leakage flow maintained a subsonic flow. Further, the tangential leakage decreased with increase in rotational speed, and when the rotational speed increased from 2000 to 5000 r\/min, the volumetric efficiency increased by approximately 8.7565%.<\/jats:p>","DOI":"10.3390\/e25020339","type":"journal-article","created":{"date-parts":[[2023,2,13]],"date-time":"2023-02-13T03:07:57Z","timestamp":1676257677000},"page":"339","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Analysis of Tangential Leakage Flow Characteristics of Oil-Free Scroll Expander for a Micro-Scale Compressed Air Energy Storage System"],"prefix":"10.3390","volume":"25","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1171-9136","authenticated-orcid":false,"given":"Jian","family":"Sun","sequence":"first","affiliation":[{"name":"School of Mechanical & Electronical Engineering, Lanzhou University of Technology, Lanzhou 730050, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bin","family":"Peng","sequence":"additional","affiliation":[{"name":"School of Mechanical & Electronical Engineering, Lanzhou University of Technology, Lanzhou 730050, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bingguo","family":"Zhu","sequence":"additional","affiliation":[{"name":"School of Mechanical & Electronical Engineering, Lanzhou University of Technology, Lanzhou 730050, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yaohong","family":"Li","sequence":"additional","affiliation":[{"name":"School of Mechanical & Electronical Engineering, Lanzhou University of Technology, Lanzhou 730050, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,2,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Zhou, Q., Du, D.M., Lu, C., He, Q., and Liu, W.Y. (2019). A review of thermal energy storage in compressed air energy storage system. Energy, 188.","DOI":"10.1016\/j.energy.2019.115993"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Olabi, A.G., Wilberforce, T., Ramadan, M., Abdelkareem, M.A., and Alami, A.H. (2021). Compressed air energy storage systems: Components and operating parameters\u2014A review. J. Energy Storage, 34.","DOI":"10.1016\/j.est.2020.102000"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Roos, P., and Haselbacher, A. (2022). Analytical modeling of advanced adiabatic compressed air energy storage: Literature review and new models. Renew. Sustain. Energy Rev., 163.","DOI":"10.1016\/j.rser.2022.112464"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"54","DOI":"10.1016\/j.applthermaleng.2014.05.094","article-title":"A review of scroll expanders for organic Rankine cycle systems","volume":"75","author":"Song","year":"2015","journal-title":"Appl. Therm. Eng."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"37","DOI":"10.2174\/2212797609666151109204948","article-title":"Recent Advances on the Oil-Free Scroll Compressor","volume":"9","author":"Peng","year":"2016","journal-title":"Recent Pat. Mech. Eng."},{"key":"ref_6","first-page":"611","article-title":"Numerical Simulation and Experimental Study of Oil-Free Double-Warp Air Scroll Compressor","volume":"56","author":"Sun","year":"2022","journal-title":"J. Shanghai Jiaotong Univ."},{"key":"ref_7","first-page":"633","article-title":"Variable thickness scroll compressor performance analysis\u2014Part I: Geometric and thermodynamic modeling","volume":"231","author":"Peng","year":"2016","journal-title":"Proc. Inst. Mech. Eng. Part E J. Process Mech. Eng."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"256","DOI":"10.1016\/j.apenergy.2016.08.030","article-title":"Experimental investigation and modeling of a hermetic scroll expander","volume":"181","author":"Fadhel","year":"2016","journal-title":"Appl. Energy"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Emhardt, S., Tian, G.H., Song, P.P., Chew, J., and Wei, M.S. (2020). CFD modelling of small scale ORC scroll expanders using variable wall thicknesses. Energy, 199.","DOI":"10.1016\/j.energy.2020.117399"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Fanti, G.R., Rom\u00e3o, D.A., de Almeida, R.B., and de Mello, P.E.B. (2020). Influence of flank clearance on the performance of a scroll expander prototype. Energy, 193.","DOI":"10.1016\/j.energy.2019.116823"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Oh, J., Jeong, H., Kim, J., and Lee, H. (2020). Numerical and experimental investigation on thermal-hydraulic characteristics of a scroll expander for organic Rankine cycle. Appl. Energy, 278.","DOI":"10.1016\/j.apenergy.2020.115672"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"239","DOI":"10.1016\/j.ijrefrig.2019.11.002","article-title":"Numerical analysis and correlations for radial and tangential leakage of gas in scroll compressors","volume":"110","author":"Pereira","year":"2020","journal-title":"Int. J. Refrig."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"531","DOI":"10.1007\/s12204-020-2163-6","article-title":"Leakage Model of Axial Clearance and Test of Scroll Compressors","volume":"25","author":"Wang","year":"2020","journal-title":"J. Shanghai Jiaotong Univ. (Sci.)"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"185","DOI":"10.3901\/JME.2015.14.185","article-title":"Investigation of Mathematical Modeling and Experiment for Variable Thickness Scroll Compressor","volume":"51","author":"Peng","year":"2015","journal-title":"J. Mech. Eng."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Li, Y.J., Zhong, Y., Meng, F., Zheng, Y.H., and Sun, D.H. (2022). Entropy Production Analysis of a Vertical Mixed-Flow Pump Device with Different Guide Vane Meridians. Entropy, 24.","DOI":"10.3390\/e24101370"},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Tian, S.G., Zhao, Y.Y., Dong, K.R., Liu, G.B., Yang, Q.C., and Li, L.S. (2021). Internal Flow and Cavitation Analysis of Scroll Oil Pump by CFD Method. Processes, 9.","DOI":"10.3390\/pr9101705"},{"key":"ref_17","first-page":"1989","article-title":"Numerical analysis of the transient leakage flow in axial clearance of a scroll refrigeration compressor","volume":"236","author":"Sun","year":"2019","journal-title":"Proc. Inst. Mech. Eng. Part E J. Process Mech. Eng."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"971","DOI":"10.1007\/s11431-020-1765-3","article-title":"Flow characteristics of tangential leakage in a scroll compressor for automobile heat pump with CO\u2082","volume":"64","author":"Zheng","year":"2021","journal-title":"Sci. China Technol. Sci."},{"key":"ref_19","first-page":"1438","article-title":"A Gas Leakage Model in the Leakage Clearance of Scroll Compressor","volume":"37","author":"Zha","year":"2016","journal-title":"J. Eng. Thermophys."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"344","DOI":"10.1504\/PCFD.2017.088795","article-title":"3D numerical calculations of tangent leakages in scroll compressor during unsteady process","volume":"17","author":"Rak","year":"2017","journal-title":"Prog. Comput. Fluid Dyn. Int. J."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1086","DOI":"10.1016\/j.applthermaleng.2017.08.115","article-title":"Analysis of the three-dimensional transient flow in a scroll refrigeration compressor","volume":"127","author":"Sun","year":"2017","journal-title":"Appl. Therm. Eng."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"19231","DOI":"10.1016\/j.ijhydene.2018.08.158","article-title":"3D transient CFD modelling of a scroll-type hydrogen pump used in FCVs","volume":"43","author":"Zhang","year":"2018","journal-title":"Int. J. Hydrogen Energy"},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Fadiga, E., Casari, N., Suman, A., and Pinelli, M. (2020). Structured Mesh Generation and Numerical Analysis of a Scroll Expander in an Open-Source Environment. Energies, 13.","DOI":"10.3390\/en13030666"},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Zheng, S.Y., Wei, M.S., Song, P.P., Hu, C.X., and Tian, R. (2020). Thermodynamics and flow unsteadiness analysis of trans-critical CO\u2082 in a scroll compressor for mobile heat pump air-conditioning system. Appl. Therm. Eng., 175.","DOI":"10.1016\/j.applthermaleng.2020.115368"},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Sun, J., Peng, B., and Zhu, B.G. (2021). Performance Analysis and Test Research of PEMFC Oil-Free Positive Displacement Compressor for Vehicle. Energies, 14.","DOI":"10.3390\/en14217329"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"328","DOI":"10.2174\/2212797614666210830154422","article-title":"Numerical Simulation and Experimental Research of Oil-Free Scroll Air Compressor Based on CFD","volume":"15","author":"Sun","year":"2022","journal-title":"Recent Pat. Mech. Eng."},{"key":"ref_27","first-page":"2065","article-title":"Laminar flow active\/passive control technology","volume":"37","author":"Zhu","year":"2016","journal-title":"Acta Aeronaut. Et Astronaut. Sin."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"97","DOI":"10.3901\/JME.2012.21.097","article-title":"Research on the Radial Labyrinth of Scroll Compressor","volume":"48","author":"Liu","year":"2012","journal-title":"J. Mech. Eng."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"493","DOI":"10.1016\/j.ijrefrig.2021.06.021","article-title":"Impact of micro-grooves in scroll wrap tips on the performance of a trans-critical CO\u2082 scroll compressor","volume":"131","author":"Zheng","year":"2021","journal-title":"Int. J. Refrig."},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Zheng, S.Y., Wei, M.S., Zhou, Y., Hu, C.X., and Song, P.P. (2022). Tangential leakage flow control with seal-grooves on the static scroll of a CO\u2082 scroll compressor. Appl. Therm. Eng., 208.","DOI":"10.1016\/j.applthermaleng.2022.118213"},{"key":"ref_31","first-page":"2778","article-title":"The internal thermodynamic characteristics and performance test of the new oil-free scroll compressor","volume":"52","author":"Sun","year":"2022","journal-title":"J. Jilin Univ. (Eng. Technol. Ed.)"},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Feng, Y.Q., Xu, J.W., He, Z.X., Hung, T.C., Shao, M., and Zhang, F.Y. (2022). Numerical simulation and optimal design of scroll expander applied in a small-scale organic rankine cycle. Energy, 260.","DOI":"10.1016\/j.energy.2022.124981"},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Liu, Z., Li, Z., Xie, D.S., and Wu, H.W. (2022). Unsteady characteristic and flow mechanism of a scroll compressor in small-scale compressed air energy storage system. J. Energy Storage, 51.","DOI":"10.1016\/j.est.2022.104368"},{"key":"ref_34","unstructured":"White, F.M. (2009). Fluid Mechanics, McGraw-Hill. [7th ed.]."}],"container-title":["Entropy"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1099-4300\/25\/2\/339\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T18:32:41Z","timestamp":1760121161000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1099-4300\/25\/2\/339"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,2,12]]},"references-count":34,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2023,2]]}},"alternative-id":["e25020339"],"URL":"https:\/\/doi.org\/10.3390\/e25020339","relation":{},"ISSN":["1099-4300"],"issn-type":[{"value":"1099-4300","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,2,12]]}}}