Fluid Mechanics & Aerodynamics

Fluid Mechanics & Aerodynamics

Effect of Relative Humidity and Nonequilibrium Condensation on the Variation of Performance Parameters in Transonic Nozzles

Document Type : Original Article

Authors
Hasan Masoudirad 1
mehdi maerefat 2
reza maddahian 3
1 PhD student, .tarbiat modares university.Tehran, Iran
2 professor,tarbiat modares university.Tehran, Iran
3 Associate Professor, Tarbiat Modares University, Tehran, Iran
Abstract
Non-equilibrium condensation of water vapor in supersonic flows significantly impacts the performance of nozzles and aerospace equipment. Under humid conditions, this phenomenon must be considered during flow design and analysis. This study investigates the effect of relative humidity on supersonic flow in a nozzle using numerical modeling and simulation of non-equilibrium water vapor condensation. The governing equations, incorporating nucleation and droplet growth processes, were solved using user-defined functions within a compressible numerical solver. Results indicate that the presence of water vapor leads to significant changes in Mach number, pressure, and temperature. For 100% relative humidity, the dry air model overestimates the Mach number by 16% compared to the wet model's prediction and underestimates outlet pressure and temperature by 43.3% and 52%, respectively. Increasing relative humidity intensifies the condensation shock, and the nucleation rate reaches its maximum at humidities above 80%. Furthermore, above 60% relative humidity, the number of condensed droplets increases sharply. Therefore, non-equilibrium water vapor condensation must be accounted for in the design of supersonic nozzles and compressors operating in humid conditions to prevent performance errors.
Keywords
Non
equilibrium Condensation Supersonic Nozzle Nucleation CFD Humidity

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[1]     Luo X, Wang J, Dooner M, Clarke J. Overview of current development in compressed air energy storage technology. Energy Procedia. 2014; 62: 603-611. DOI 10.1016/j.egypro.2014.12.059
[2]     Mousavi SB, Ahmadi P, Pourahmadiyan A, Hanafizadeh P. Transient thermodynamic modeling and economic analysis of an adiabatic compressed air energy storage (A-CAES) based on cascade packed bed thermal energy storage with encapsulated phase change materials. Energy Conversion and Management. 2021; 243: 114379. DOI 10.1016/j.enconman.2021.114379.
[3]     Haskell RW. Gas turbine compressor operating environment and material evaluation. In: Turbo Expo: Power for Land, Sea, and Air. American Society of Mechanical Engineers; 1989; 79177. DOI Not available.
[4]     Alhazmy MM, Jassim RK, Zaki GM. Performance enhancement of gas turbines by inlet air-cooling in hot and humid climates. International Journal of Energy Research. 2006; 30(10): 777-797. DOI 10.1002/er.1182.
[5]     Al-Fahed SF, Alasfour FN, Abdulrahim HK. The effect of elevated inlet air temperature and relative humidity on cogeneration system. International Journal of Energy Research. 2009; 33(15): 1384-1394. DOI 10.1002/er.1546.
[6]     Shukla AK, Sharma A, Sharma M, Mishra S. Performance improvement of simple gas turbine cycle with vapor compression inlet air cooling. Materials Today: Proceedings. 2018; 5(9): 19172-19180. DOI 10.1016/j.matpr.2018.06.275.
[7]     Sanaye S, Tahani M. Analysis of gas turbine operating parameters with inlet fogging and wet compression processes. Applied Thermal Engineering. 2010; 30(2-3): 234-244. DOI 10.1016/j.applthermaleng.2009.07.005.
[8]     Sun J, Chen W, Li Y, Zhang H. The effect of wet compression on a centrifugal compressor for a compressed air energy storage system. Energies. 2019; 12 (5): 906. DOI 10.3390/en12050906.
[9]     Prandtl L. Attidel Convegno Volta. Volume XIV. 1st Edition. Roma: Reale Academia D’Italia; 1936.
[10]  Schnerr GH, Mundinger G. Similarity, drag and lift in transonic flow with given internal heat addition. European Journal of Mechanics B/Fluids. 1993; 12(5): 597-612. DOI Not available.
[11]  Wiśniewski P, Dykas S, Majkut M, Zhang G. Selection of a steam condensation model for atmospheric air transonic flow prediction. Applied Thermal Engineering. 2022; 203: 117922. DOI 10.1016/j.applthermaleng.2021.117922.
[12]  Dykas S, Wróblewski W. Numerical modelling of steam condensing flow in low and high-pressure nozzles. International Journal of Heat and Mass Transfer. 2012; 55(21-22): 6191-6199. DOI 10.1016/j.ijheatmasstransfer.2012.06.029.
[13]  Wang J, Gu H. A study of moist air condensation characteristics in a transonic flow system. Energies. 2021; 14(13): 4052. DOI 10.3390/en14134052.
[14]  Jabir E, Brezgin D, Aronson K, Kim HD. Numerical estimation of non-equilibrium condensation of steam in supersonic nozzles. Journal of Mechanical Science and Technology. 2018; 32(10): 4531-4540. DOI 10.1007/s12206-018-0901-6.
[15]  Cai L, He M, Huang KZ, Xiong W. Computational fluid dynamics simulation of the supersonic steam ejector using different condensation models. Thermal Science. 2019; 23(Suppl. 3): S933-S941. DOI 10.2298/TSCI180601179C.
[16]  ANSYS, Inc. ANSYS Fluent User's Guide, Release 2023 R1. ANSYS, Inc.; 2023.
[17]  Kalikmanov VI, Van Dongen MEH. Semiphenomenological theory of homogeneous vapor–liquid nucleation. Journal of Chemical Physics. 1995; 103(10): 4250-4255. DOI 10.1063/1.469589.
[18]  Young JB. The spontaneous condensation of steam in supersonic nozzles. Physicochemical Hydrodynamics. 1982; 3(1): 57-82. DOI Not available.
[19]  Charton H, Perret C, Phan HT. Analysis of supersonic flows inside a steam ejector with liquid–vapor phase change using CFD simulations. MDPI Proceedings. 2024; 4(1): 1. DOI 10.3390/proceedings4010001.
Moses CA, Stein GD. On the growth of steam droplets formed in a Laval nozzle using both static pressure and light scattering measurements. Journal of Fluids Engineering. 1978; 100(3): 311-322. DOI 10.1115/1.3448672.
Fluid Mechanics & Aerodynamics
Volume 14, Issue 1 - Serial Number 35
Spring and summer
September 2025
Pages 51-62

  • Receive Date 13 April 2025
  • Revise Date 01 July 2025
  • Accept Date 29 July 2025
  • Publish Date 23 August 2025