Fluid Mechanics & Aerodynamics

Fluid Mechanics & Aerodynamics

Numerical investigation of the effect of the cooling flow entry angle on the stacked ring cooling effectiveness

Document Type : Original Article

Authors
Sajjad Ranjbar 1
Mohammad Mehdi Doustdar 2
Kazem Delsoz 1
1 Master's Degree, Imam Hossein Comprehensive University, Tehran, Iran
2 Professor, Imam Hossein Comprehensive University, Tehran, Iran
Abstract
In this research, the design of a cooling system for the combustion chamber of a ramjet engine and the effect of various cooling methods on the temperature distribution of the combustion chamber wall have been addressed. The components of the ramjet engine, types of ramjet engine combustion chambers, and the governing thermodynamics of the ramjet engine components have been studied. After determining the engine operating conditions using thermodynamic relations, the inlet conditions of the combustion chamber were specified. Following the determination of the flow conditions in the combustion chamber using existing empirical relations, the necessity and effect of film cooling were investigated. The numerical solution was validated with obtained experimental results. Using the numerical solution, film cooling methods with a simple gap, spray cooling, and a punched ring were examined. Various cases were studied by changing the geometry dimensions of the lip and the cooling gap size in spray cooling for a single cooling ring, and the required bypass air flow rate was investigated. Then, for a punched ring, the cooling effect was studied by changing the inlet flow angle and incorporating a lip. Spray cooling yields favorable results when the ratio of the lip height to the gap size is equal to or greater than one. The punched ring with a lip and angles close to 90 degrees provides favorable results.
Keywords
Ramjet engine
Film cooling
Combustion chamber
Impingement cooling
[1]. Mattingly JD. Elements of propulsion: Gas turbines and rockets. Reston (VA): American Institute of Aeronautics and Astronautics; 2006. DOI:10.2514/4.103711
[2]. Hojnacki JT. Ramjet engine fuel injection studies. Air Force Aero Propulsion Laboratory; 1972.
[3]. Mattingly JD, Heiser WH, Pratt DT. Aircraft engine design. 2nd ed. Reston (VA): American Institute of Aeronautics and Astronautics; 2002.
[4]. Song JW, Lee KW, Cho HH, Hwang KY, Ham HC. Film cooling system for ramjet combustion chamber. In: Proceedings of the Korean Society of Propulsion Engineers Conference; 2009. p. 406-407.
[5]. Baldauf S, Scheurlen M, Schulz A, Wittig S. Correlation of film cooling effectiveness from thermographic measurements at engine-like conditions. Journal of Turbomachinery. 2002;124(4):686-698. DOI:10.1115/1.1504443.
[6]. Colban WF, Thole KA, Bogard D. A film-cooling correlation for shaped holes on a flat-plate surface. Journal of Turbomachinery. 2011;133(1):011002. DOI:10.1115/1.4002064
[7]. Cutbirth JM, Bogard DG. Evaluation of pressure side film cooling with flow and thermal field measurements: Part I: Showerhead effects. Journal of Turbomachinery. 2002;124(4):679-685. DOI:10.1115/1.1504441.
[8]. Bons JP, MacArthur CD, Rivir RB. The effect of high free-stream turbulence on film cooling effectiveness. Journal of Turbomachinery. 1996;118(4):814-825. DOI:10.1115/1.2840939.
[9]. Kadotani K, Goldstein RJ. Effect of mainstream variables on jets issuing from a row of inclined round holes. Journal of Engineering for Power. 1979;101(4):619-624. DOI:10.1115/1.3446486.
[10]. Foster NW, Lampard D. The flow and film cooling effectiveness following injection through a row of holes. Journal of Engineering for Power. 1980;102(3):584-588. DOI:10.1115/1.3230306.
[11]. Amer AA, Jubran BA, Hamdan MA. Comparison of different two-equation turbulence models for prediction of film cooling from two rows of holes. Numerical Heat Transfer, Part A: Applications.1992;21(2):143-162. DOI:10.1080/10407789108944870
[12]. Schmidt DL, Sen B, Bogard DG. Film cooling with compound angle holes: adiabatic effectiveness. Journal of Turbomachinery. 1996;118(4):807-813. DOI:10.1115/1.2840938.
[13]. Seo HJ, Lee JS, Ligrani PM. The effect of injection hole length on film cooling with bulk flow pulsations. International Journal of Heat and Mass Transfer. 1998;41(22):3515-3528. DOI:10.1016/S0017-9310(98)00042-8.
[14]. Schuchkin V, Osipov M, Shyy W, Thakur S. Mixing and film cooling in supersonic duct flows. International Journal of Heat and Mass Transfer. 2002;45(22):4451-4461. DOI:10.1016/S0017-9310(02)00151-5.
[15]. Leger B, Miron P, Emidio JM. Geometric and aero-thermal influences on multiholed plate temperature: application on combustor wall. International Journal of Heat and Mass Transfer. 2003;46(7):1215-1222. DOI:10.1016/S0017-9310(02)00396-4.
[16]. Tao Z, Yang X, Ding S, Xu G, Wu H, Deng H, Luo X. Experimental study of rotation effect on film cooling over the flat wall with a single hole. Experimental Thermal and Fluid Science. 2008;32(5):1081-1089. DOI:10.1016/j.expthermflusci.2007.12.003.
[17]. Jovanović MB, De Lange HC, Van Steenhoven AA. Effect of hole imperfection on adiabatic film cooling effectiveness. International Journal of Heat and Fluid Flow. 2008;29(2):377-386. DOI:10.1016/j.ijheatfluidflow.2007.11.008.
[18]. Liu JS, Malak MF, Tapia LA, Crites DC. Enhanced film cooling effectiveness with new shaped holes. In: Proceedings of ASME Turbo Expo 2010: Power for Land, Sea, and Air. 2010. Paper No.: GT2010-22774. DOI:10.1115/GT2010-22774.
[19]. Ghorab MG. Cooling performance and flow-field analysis of a hybrid scheme with different outlet configurations. Applied Thermal Engineering. 2013;61(2):799-816. DOI:10.1016/j.applthermaleng.2011.05.020.
[20]. Kalghatgi P, Acharya S. Improved film cooling effectiveness with a round film cooling hole embedded in a contoured crater. Journal of Turbomachinery. 2015;137(10):101006. DOI:10.1115/1.4030395
[21]. Taheri Y, Rajabi Zargarabadi M, Jahromi M. Experimental and numerical study on the effects of shaped multi-holes on the effectiveness of film cooling. Journal of Thermal Analysis and Calorimetry. 2021;146:1723-1733. DOI:10.1007/s10973-020-10157-4.
[22]. Anderson JD. Fundamentals of aerodynamics. 5th ed. New York (NY): McGraw-Hill; 2010.
[23]. Anderson JD Jr. Hypersonic and high-temperature gas dynamics. 2nd ed. Reston (VA): American Institute of Aeronautics and Astronautics; 2006.
[24]. Modest MF. Radiative heat transfer. 3rd ed. Amsterdam: Academic Press; 2013.
[25]. Lefebvre AH, Ballal DR. Gas turbine combustion: alternative fuels and emissions. 3rd ed. Boca Raton (FL): CRC Press; 2010.
[26]. Han JC, Dutta S, Ekkad S. Gas turbine heat transfer and cooling technology. 2nd ed. Boca Raton (FL): CRC Press; 2012.
Fluid Mechanics & Aerodynamics
Volume 14, Issue 2 - Serial Number 36
Autumn and Winter
February 2026
Pages 37-55

  • Receive Date 10 December 2025
  • Revise Date 21 January 2026
  • Accept Date 05 February 2026
  • Publish Date 20 February 2026