• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.2
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• pp.9-15
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• 2013

An effect of a spiral turbulent ring, so-called Shchelkin spiral, on a detonation performance was studied experimentally for acetylene and oxygen mixture. A couple of dynamic pressure transducers were used to calculate a detonation wave velocity by a time difference between two pressure peaks. In addition, impulse was measured by a load cell and the impulse was used to analyze the spiral effect on the detonation performance. A CFD analysis was adopted to calculate mass flow rates of the propellants and the minimum filling time. The maximum velocity and pressure were measured at the equivalence ratio of 2.4, and the measured values showed similar trend to C-J conditions calculated from CEA. For the shorter chamber with the short spiral, the maximum detonation velocity was appeared. In contrast, the longer chamber without the spiral showed the maximum thrust performance.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.15 no.1
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• pp.1-10
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• 2007

When detonation is occurred, the working fluid is compressed itself, though there are no other devices that compress the fluid. As a result, an engine which uses detonation for a combustion process doesn't need moving parts so that the engine can be lighter than other engines ever exist, and such an engine is often referred to as a pulse detonation engine. Since using detonation has higher performance than using deflagration, many studies have been attempting to control and analyze the engines using detonation as combustion. The purpose of this study is to analyze the hybrid cycle which is consisted of Brayton and Pulse Detonation Engine cycle. At first, we set the theoretical basis of detonation analysis, and after that we consider two hybrid cycles; a turbojet hybrid cycle and a turbofan hybrid cycle. The more energy released, the higher detonation Mach number the detonation wave has. In general, a cycle which has a detonation process has higher performances but thermal efficiency of hybrid turbofan engine.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.624-628
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• 2011

To develop a pulse detonation engine, it needs to understand the mechanism of a detonation initiation, and establish the methods for measuring and analyzing the detonation phenomenon. In this study, DDT tube, which use oxygen-acetylene propellant mixture, were designed and manufactured, and the effect of equivalent ratio and Schelkin spiral on the characteristics of the detonation initiation were discussed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.8
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• pp.1989-1998
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• 1995

Characteristics of the flame propagation for normal and abnormal combustion in hydrogen premixture in a cylindrical constant-volume combustion chamber are studied numerically. A detailed hydrogen oxidation kinetic mechanism, mixture transport properties and a model describing spark ignition process are used. The calculated pressure-time history of the stable deflagration wave propagation agrees well with the experiment. The ignition of the premixture in the unburned gas, initiated by the hot spot, causes a transition from deflagration to detonation under some initial temperature and pressure. Under the initial conditions with high temperature and pressure, excessive ignition energy initiates a strong blast wave and a detonation wave that follows. The chemical reaction in the detonation wave is much more vigorous than that in the deflagration wave and the peak pressure in the detonation wave is much higher than the equilibrium value.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.05a
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• pp.221-224
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• 2003

A numerical study is carried out for the detonation wave propagation through a T-branch. The T-branch is a crucial part of the combustion wave igniter, a novel concept of rocket ignition system aimed for the simultaneous ignition of multiple combustion chambers by delivering detonation waves. Euler equation and induction parameter equation are used as governing equations with a reaction term modeled from the chemical kinetics database obtained from a detailed chemistry mechanism. Second-order accurate implicit time integration and third-order space accurate TVD algorithm were used for solution of the coupled equations. Over two-million grid points enabled the capture of the dynamics of the detonation wave propagation including the degeneration and re-initiation phenomena, and some of the design factors were be obtained for the CWI flame tubes.