GB2169034A - Jet engine having ramjet driven compressor - Google Patents

Abstract

In a propulsion engine in which an axial-flow compressor 6 supplies compressed working fluid to a combustion chamber 45 which exhausts through a propelling nozzle 40, the compressor is driven by ramjet motors 2 placed at the tips of some of the first stage compressor blades 4. Details of fuel and low- voltage electricity supply to the ram jets is also disclosed. <IMAGE>

Description

SPECIFICATION Ramjet-compressor jet engine This invention relates to using ramjet as the prime mover for the jet engine compressor instead of the turbine.

The simplest of all air-breathing engines is the ramjet, where no rotating element is exist which allows operation at very high temperatures which in sequence allows operation at high flight Mack numbers. This in addition to its design and manufacturing simplicity, insensitive to fuel type, etc. A disadvantage of ramjet is that the pressure ratio is strictly limited by flight speed and diffuser performance.

The most serious sequence of this is the fact that the ramjet cannot develop static thrust and, therefore, connot accelarate a vehicle from a standing start. New jet engine having the advantages of the ramjet and able to develop static thrust is proposed.

According to the present invention, the engine consists of a mechanical compressor in the inlet duct, a combustion chamber and an exhaust nozzle is presented, The compressor is driven by small ramjets mounted at the tips of some of the first statage blades of the compressor, so that even at zero flight speed air could be drawn into the engine. The compressed air then mixed with the fuel and burned in the combustion chamber. The hot gases are then expelled through the propelling nozzle. Startor is provided to accelarate the ramjet to its operating speed after which the startor will be disengaged and ramjets takes over. Fuel supplies to ramjets is provided from the main tank through a rotating joint fixed on the compressor hollow shaft. Amechanical seal is used to prevent fuel leakage at the joint.Low voltage electrical supplies to ramjets is provided through a stationar graphite brush incontact with a rotating brass ring fixed on the compressor hollow shaft. Both fuel and electrical lines continue along the inside of the compressor hollow shaft, through the ramjets supporting blades and to the ramjet engines.

Aspecific embodiment of the invension will now be described by way of example with reference to accompanying drawings in which: Figure 1 shows schematic diagram of the engine; Figure 2 shows detailed drawing of the rotating joints. Refer to Fig. 1 ramjets 2 are mounted and fixed at the tips of two of blades 4 of the first stage of the axial-flow compressor 6. The fuel and low voltage electrical supplies for the ramjets are provided from the main tank and through a rotating joint 12. The details of which is shown diagrammatically in Fig. 2, where a double-mechanical seal is used to prevent fuel leakage at the joint. The double mechanical seal comprises two rotating elements 19, which are fixed on the compressor hollow shaft 16, and the stationary part 14 which is fixed to the back stationary center body 20.The fuel enters from port 22 to room 24, from which it flows into room 26 inside the compressor hollow shaft, through the holes 29 made in it.

From room 26 it flows through pipe 99 which runs inside the compressor hollow shaft and inside the ramjets supporting blades 4 to the ramjets 2. The electrical supply transfer from the stationary graphite brush 30 to the rotating mass ring 34 fixed around the compressor shaft. The electrical cable 32 then continue its way to the ramjets through the hollow compressor shaft and ramjets supporting blades.

A startor with a necessary reduction gear is provided (not shown) to accelerate the system to the required operating speed of the ramjets. After that the startor is automatically disengaged and the ramjets take over. Now the compressor 6 which is driven by the ramjets 2 draws air inside the main engine. The compressed air then mixed with the fuel comes out from the fuel burners 39 and burned in the combustion chamber 45. The hot gases then expelled out from the propelling nozzle 40. In Fig. 1, 42 represent flame holder and the ignition system is not shown. The exhaust gases from the driving ramjets is guided axially through the external duct 44.

1. Ramjet-Compressor jet engine comprise a conventional propulsion engine where the gas turbine is despensed with Ramjet motors which are mounted at the tips of some of the first stage compressor blades is used instead to drive the engine compressor.

2. Ramjet-Compressor jet engine as claimed in claim 1 wherein a circular external duct is used to collect and guide axially the exhaust gases from the driving ramjets so that augmenting the engine thrust.

3. Ramjet-Compressor jet engine as claimed in claim 1 wherein a proper mechanical seal chamber and power slip ring is provided to feed the rotating ramjets with fuel and electricity.

4. Ramjet-Compressor jet engine as described herein with reference to Fig. 1 and 2 of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Ramjet-compressor jet engine This invention relates to using ramjet as the prime mover for the jet engine compressor instead of the turbine. The simplest of all air-breathing engines is the ramjet, where no rotating element is exist which allows operation at very high temperatures which in sequence allows operation at high flight Mack numbers. This in addition to its design and manufacturing simplicity, insensitive to fuel type, etc. A disadvantage of ramjet is that the pressure ratio is strictly limited by flight speed and diffuser performance. The most serious sequence of this is the fact that the ramjet cannot develop static thrust and, therefore, connot accelarate a vehicle from a standing start. New jet engine having the advantages of the ramjet and able to develop static thrust is proposed. According to the present invention, the engine consists of a mechanical compressor in the inlet duct, a combustion chamber and an exhaust nozzle is presented, The compressor is driven by small ramjets mounted at the tips of some of the first statage blades of the compressor, so that even at zero flight speed air could be drawn into the engine. The compressed air then mixed with the fuel and burned in the combustion chamber. The hot gases are then expelled through the propelling nozzle. Startor is provided to accelarate the ramjet to its operating speed after which the startor will be disengaged and ramjets takes over. Fuel supplies to ramjets is provided from the main tank through a rotating joint fixed on the compressor hollow shaft. Amechanical seal is used to prevent fuel leakage at the joint.Low voltage electrical supplies to ramjets is provided through a stationar graphite brush incontact with a rotating brass ring fixed on the compressor hollow shaft. Both fuel and electrical lines continue along the inside of the compressor hollow shaft, through the ramjets supporting blades and to the ramjet engines. Aspecific embodiment of the invension will now be described by way of example with reference to accompanying drawings in which: Figure 1 shows schematic diagram of the engine; Figure 2 shows detailed drawing of the rotating joints. Refer to Fig. 1 ramjets 2 are mounted and fixed at the tips of two of blades 4 of the first stage of the axial-flow compressor 6. The fuel and low voltage electrical supplies for the ramjets are provided from the main tank and through a rotating joint 12. The details of which is shown diagrammatically in Fig. 2, where a double-mechanical seal is used to prevent fuel leakage at the joint. The double mechanical seal comprises two rotating elements 19, which are fixed on the compressor hollow shaft 16, and the stationary part 14 which is fixed to the back stationary center body 20.The fuel enters from port 22 to room 24, from which it flows into room 26 inside the compressor hollow shaft, through the holes 29 made in it. From room 26 it flows through pipe 99 which runs inside the compressor hollow shaft and inside the ramjets supporting blades 4 to the ramjets 2. The electrical supply transfer from the stationary graphite brush 30 to the rotating mass ring 34 fixed around the compressor shaft. The electrical cable 32 then continue its way to the ramjets through the hollow compressor shaft and ramjets supporting blades. A startor with a necessary reduction gear is provided (not shown) to accelerate the system to the required operating speed of the ramjets. After that the startor is automatically disengaged and the ramjets take over. Now the compressor 6 which is driven by the ramjets 2 draws air inside the main engine. The compressed air then mixed with the fuel comes out from the fuel burners 39 and burned in the combustion chamber 45. The hot gases then expelled out from the propelling nozzle 40. In Fig. 1, 42 represent flame holder and the ignition system is not shown. The exhaust gases from the driving ramjets is guided axially through the external duct 44. CLAIMS

1. Ramjet-Compressor jet engine comprise a conventional propulsion engine where the gas turbine is despensed with Ramjet motors which are mounted at the tips of some of the first stage compressor blades is used instead to drive the engine compressor.

2. Ramjet-Compressor jet engine as claimed in claim 1 wherein a circular external duct is used to collect and guide axially the exhaust gases from the driving ramjets so that augmenting the engine thrust.

3. Ramjet-Compressor jet engine as claimed in claim 1 wherein a proper mechanical seal chamber and power slip ring is provided to feed the rotating ramjets with fuel and electricity.

4. Ramjet-Compressor jet engine as described herein with reference to Fig. 1 and 2 of the accompanying drawings.