DETERMINATION OF BREAKING CHARACTERISTICS IN THE PRE-COMBUSTION CHAMBER OF A COMBINED RAMJET ENGINE ON A POWDERED ALUMINUM FUEL TAKING INTO ACCOUNT AIR BRAKING IN AIR INTAKE DEVICE

The paper considers a combined ramjet engine powered by powdered aluminum fuel . The prototype was a combined solid-fuel ramjet engine. The advantages of the engine under consideration are given. An example of the combustion of finely dispersed aluminum powder is considered, from which it follows that the initial temperature of the aluminum powder will affect the stall characteristics in the pre-chamber. The following characteristics of the PAF ramjet were determined: the temperature of air stagnation in the air intake device, the temperature of the mixture of aluminum powder and the stalled air flow, the excess air ratio, and the stall characteristics in the pre-chamber taking into account the air stagnation temperatures. All parameters are de-termined for engine operating altitudes equal to 0.5, 10 and 18 km. A comparison is made of the limiting flame propagation ve-locities under standard conditions and with an incident air flow. Based on the obtained values of the characteristics, the interval of values of the coefficient of air sampling from the inlet to the pre-chamber of the ramjet engine on the PAF was determined, corresponding to the maximum possible areas of the engine operating parameters. Using the obtained values of characteristics, the combustion process of powdered aluminum in the pre-chamber of a ramjet engine takes place without flame blowout, which excludes unstable operation of the propulsion system as a whole. The use of powdered aluminum makes it possible to regulate the thrust in a wide range of values, and a high initial temperature of the air entering the pre-chamber for repeated switching on and off of the engine. Based on the available data, the type of engines under consideration is suitable for combat missiles of various classes, but the most suitable for aircraft-based missiles.