Performance study of a water ramjet engine

A performance study of a water ramjet engine is described.The engine is powered by the reaction of a magnesium-based propellant and ingested water.In this study,a solid propellant,which consisted of a large percentage of magnesium,a binder and a small amount of oxidant,was used as a hydro reactive fuel.Cold water was injected into the combustion chamber as a main oxidant.A scaled-down experimental engine was tested in a direct-connect ground testing system to characterize the factors influencing the engine performance.The results show that the increasing of total water/fuel ratio,an addition of secondary water intake along the combustion chamber,a larger magnesium content in the solid propellant,a smaller primary water injection angle towards the coming main flow,and a higher primary injection pressure were all able to promote the engine performance.The maximum engine performance was obtained in test 08,and with all tests,an appropriate set of parameters and conditions for the optimum engine performance were determined

Model optimization method and connected-pipe experiment of a liquid fuel ramjet engine

The optimization method of a mathematical model and connected-pipe experimental technique for a test in altitude test facility (ATF) of a liquid fuel ramjet engine was researched.The optimization of the simple mathematical model was divided into two steps.Firstly,using the test engine's geometry configuration size data,a preliminary adjustment was done.Secondly,using experimental test data,the components' experiential coefficients were modified appropriately.Emphasis was laid on the simulation technique of flight condition and parameters measurement method.The experimental technique was applied to a ramjet ATF test successfully.The comparison results show that the optimized-model has higher precision and the nozzle gross thrust difference drops from 12% to about 4%.

Overspeeding characteristics of turbomachinery for gas generator cycle air turbo ramjet engine

The main interest in the current study focuses on the possibility of overspeeding for the gas-generator cycle air turbo ramjet(GG-ATR)engine.The authors developed the air turbo ramjet engine and investigated its compressor performance.Based on those data,the authors developed the analytical code for the air turbo ramjet engine,which calculates the performances of turbomachinery,gas-generator,and ram combustor.The previous study described that the rotor overspeeding would not occur in the air turbo rocket engine.However,the current results show that degraded ram combustion can decrease the compressor pressure ratio and the compressor power.This reduced compressor power can cause overspeeding for the air turbo ramjet engine.The experimental results of compressor power and turbine inlet pressure support those analytical results.

Statistical model for combustion of high-metal magnesium-based hydro-reactive fuel

We investigate experimentally and analytically the combustion behavior of a high-metal magnesium-based hydro- reactive fuel under high temperature gaseous atmosphere. The fuel studied in this paper contains 73% magnesium powders. An experimental system is designed and experiments are carried out in both argon and water vapor atmo- spheres. It is found that the burning surface temperature of the fuel is higher in water vapor than that in argon and both of them are higher than the melting point of magnesium, which indicates the molten state of magnesium particles in the burning surface of the fuel. Based on physical considerations and experimental results, a mathematical one-dimensional model is formulated to describe the combustion behavior of the high-metal magnesium-based hydro-reactive fuel. The model enables the evaluation of the burning surface temperature, the burning rate and the flame standoff distance each as a function of chamber pressure and water vapor concentration. The results predicted by the model show that the burning rate and the surface temperature increase when the chamber pressure and the water vapor concentration increase, which are in agreement with the observed experimental trends.