Received 24 January 2006, revised 19 June 2007 Defence Science Journal, Vol. 58, No. 3, May 2008, pp. 327-337 Ó 2008, DESIDOC 327 Keywords: Ramjet engine, air intake, combustor, numerical simulation, internal flow, air/fuel ratio 1. INTRODUCTION Ramjet engines are lighter than rockets since they utilise ambient air as the oxidiser for combustion of fuel. The major constituents of a liquid ramjet engine are air-intake, combustion chamber, and nozzle. The full engine simulation is useful for understanding the various important aspects of ramjet internal flows that include shockwave/boundary layer interactions, inlet/combustor coupling, flame holding and spreading, and combustion dynamics. Thomas 1 presented documented facts about the current status of ramjets and ramjet technology and concluded that ramjets possess the unique ability to provide continuous thrust, sustained high supersonic speed and high specific impulse. Hebrard 2 , et al. employed a combined approach using experiments in isothermal conditions and simple computation models to study the global performances of various Numerical Analysis of Integrated Liquid Ramjet Engine G. Raja Singh Thangadurai 1 , B.S. Subhash Chandran 1 , V. Babu 2 , and T. Sundararajan 2 1 Defence Research & Development Laboratory, Hyderabad-500 058 2 Indian Institute of Technology Madras, Chennai-600 036 ABSTRACT The numerical simulation of an integrated, liquid-fuelled ramjet engine comprising supersonic air intake, subsonic combustor and a convergent-divergent nozzle has been carried out and the results are discussed in this paper. These results include cold flow studies, heat addition in the combustor and full engine analysis with coupled simulation of supersonic air-intake and combustion chamber along with the nozzle. Overall ramjet operation depends on the performance of the air intake and the combustion chamber. The coupling phenomena are very dominant and performance of air intake is affected vastly by the combustor operation and vice versa. In this paper, a numerical analysis of integrated liquid ramjet engine considering coupling phenomena between various sub-systems viz., air intake, combustor and nozzle has been reported. ramjets. Calzone 3 carried out a study of the international developments on missile ramjet propulsion. The choice and techniques to be used during the design of a liquid-fuelled ramjet engine were described in detail by Cazin and Laurent 4 .The specific features of the constituents of a ramjet engine such as the air supply system, fuel supply system, combustion chamber and the nozzle, were discussed. Conway and Johansson 5 dealt with the development and validation of a methodology for simulation of ramjet -powered missiles using computational fluid dynamics (CFD). Simultaneous calculations of the internal and external flows were carried out by coupling a quasi one- dimensional ramjet engine model with a CFD solver. A thermally perfect gas assumption was adopted to enable accurate modelling of the hot nozzle gas flow. Tip to tail calculations were carried out on two ramjet-powered vehicles brought to you by CORE View metadata, citation and similar papers at core.ac.uk provided by Defence Science Journal