A rocket's engine usually uses fuel and oxygen as propellants to increase the rocket's projection during launch. Nowadays, metallic ingredients are commonly used in the rocket’s operation to increase its performance. Metallic ingredients have a high energy density, flame temperature, and regression rate that are important factors in the propulsion process. There is a wide range of additives have been reported so far as catalysts for rocket propulsion. The studies show that the presence of metal additives improves the regression rate, specific impulse and combustion efficiency. Herein, the common energetic additives for rocket propulsion such as metal and light metals are reviewed. Besides the effect of these energetic particles on the regression behaviors of base (hybrid) fuel has been exclusively discussed. This paper also proposed a new alloy namely high entropy alloys (HEAs) as a new energetic additive that can potentially increase the performance of the rocket propellant system.
Detonation is a shock wave obtained from the energy that releases after the combustion. Chapman-Jouguet(CJ) theory can be used to identify the behaviour of the detonation in gasses. Pulse Detonation Engines (PDEs) is one of the engines that implement the detonation in its combustion system. The Humphrey cycle is the thermodynamic cycle which is similar to the Pulse Detonation Engines (PDEs). It is the modification of the Brayton cycle where the constant-pressure heat addition process of the Brayton cycle is replaced by a constant-volume heat addition process. The Humphrey cycle can provide the pressure rise combustion by utilizing the shock inside the combustion chamber. Compared to the Brayton cycle, the Humphrey cycle has higher thermodynamic efficiency. However, the detonation process has unsteady combustion which makes it more difficult to handle. The purpose of the study is to calculate the performance of the aircraft by using alternative fuel in the ZND model. An analytical model is started by having the molecular structure of each biofuel and it has been used to determine detonation velocity, Mach number at C-J point, temperature ratio, pressure ratio, density ratio, Brayton and Humphrey efficiency, specific impulse, and specific thrust. In addition, the physical properties of the flow are investigated by changing the initial temperature, initial pressure, and mass flux. The pressure ratio, temperature ratio, and density ratio will all decrease as the initial pressure varies. The variation of mass flux and initial temperature, on the other hand, generates the opposite outcome as the change of pressure. The feasibility of the fuels in the detonation combustion can be known as they show high propulsive performance after the initial condition is changing.
A low regression rate is a major limitation in the hybrid rocket propulsion system. This paper is to study the regression rate characteristics of a cylindrical solid grain with cryogenic propellants. Paraffin (P) fuel is coupled with two types of oxidizers, namely gaseous oxygen (GOX) and nitrous oxide (N2O). ANSYS software is used as the CFD platform to observe the hybrid rocket flow-fields. The modelling values obtained from the pressure, temperature, velocity, and wall heat flux contours are used to calculate the hybrid rocket performance in terms of regression rate, thrust, specific impulse, characteristic velocity, and exit Mach number. The numerical results show that the mass-flow-inlet boundary conditions, initial design feature, and type of propellant play an important role in the enhancement of hybrid rocket performance. Result shows that enhanced of 68 % of the regression rate, 59 % of thrust, 6 % of specific impulse and exit Mach number, and % of characteristic velocity by improved 50% of mass flow rate. Due to the high flame temperature, the GOX/P propellants produce the best hybrid rocket motor compared with the others.
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