AJAX Concept‎ > ‎

MHD-control of the ionized air flow in the engine

Currently, the ramjet engine with a supersonic combustion (scramjet), wherein for pre-compression of the oncoming airflow the surface of the vehicle is used, is considered the most promising one for mastering hypersonic flight velocities. However, a complicated flow structure in its duct increases the likelihood of flow separation and makes it difficult to organize efficient fuel combustion. With flight velocity below calculated one, for scramjet air inlet mass flow rate of the air and flow contraction degree decrease. Apart from that, with flight velocity change the structure of the flow in the scramjet re-arranges significantly, and thus the engine proves to be effective only in a rather low velocity range. As such, we investigate a totality of issues having to do with the development, within the frame of the Ajax conception, of a new engine – ramjet with MHD interaction (in our terminology – magneto-plasma-chemical engine, abbreviated to MPCE). 

MPCE scheme: 0-1-air inlet; 1-2,c – internal MHD-generator; 2-3 – combustion chamber; 
3-4,d – MHD accelerator; 4-5 – nozzle; a-ionizer; b-external MHD-generator; c- onboard systems

This simplified MPCE scheme in essence is a scramjet with MHD systems installed in its duct. In the external part of the air intake the compression of the oncoming flow in N shock-wave system and its ӨN net angle turn is realized, and in the internal – the reverse flow reversal at the angle ӨN and its additional compression. Ionizer is used for creation of the necessary flow conductivity when the natural conductivity does not provide the required degree of MHD interaction. The external MHD generator is used to control flow profile, air flow control in MPCE, and to increase increase. The internal MHD generator is used to increase pressure and prevent separation flows evolving. Electricity output of MHD generators is consumed on meeting power requirements of the ionizer, onboard equipment, as well as an additional acceleration of the combustion yields in the MHD accelerator

During MHD braking of air flow, its kinetic energy is converted into electrical one which shall be aimed at:

  1. realization of the functions of controlled air intake optimizing the MPCE’ state properties;
  2. reducing drag due to the interaction of plasma-air hypersonic flow with the surface of the airframe; 
  3. operation of powerful onboard systems of directed energy converting electrical energy into controlled beaming used for a wide range of innovative applications and defense tasks, as well as ensuring the work of onboard complex avionics.

Volumetric deceleration by magnet field allows to create the controlled air inlet, optimize  the state properties of the air flow in the MPCE’ duct (in combustion chamber’ too) and in so doing to guarantee creation of a ducted jet-engine operating in a wide range of hypersonic velocities. And no longer there exists the need to use hardly realizable methods of mechanical controlling of geometrical parameters of the engine. Modern advances in the fields of electrical engineering and magneto engineering suggest that the MHD systems of MPCE will have quite acceptable weight-and-size characteristics.