Rocket Turbopump Starter Using Compressed Air Tapping
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Solution Overview
Problem
Existing methods for starting rocket engine turbopumps in aircraft subject the turbines to significant thermal shocks and are bulky, heavy, and costly due to the use of high-temperature hot gases, which reduces their lifespan and increases maintenance needs.
Innovation Solution
A device that uses compressed air from a turbine engine's compressor stage to start the turbopump, avoiding thermal shocks by maintaining lower temperatures and incorporating a combustion chamber supplied with liquid propellants for ignition, along with cooling means and control valves for controlled rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If hot gases from combustion chamber or pyrotechnic starter are used to start the turbopump, then the turbine can be driven into rotation, but the turbine undergoes significant thermal shock which reduces its lifespan and increases maintenance needs
Solution Approach 1:
The patent applies preliminary action by first introducing compressed air at moderate temperature (600°C maximum) to gradually heat the turbine before introducing hotter combustion gases. This preparatory heating step prevents thermal shock when the turbine later operates with high-temperature rocket propellant combustion gases, thereby extending turbine lifespan while achieving the required rotation speed for pump operation
Solution Approach 2:
The patent uses compressed air as an intermediary substance to transfer energy to the turbine in a controlled manner. This intermediary medium allows the turbine to be accelerated to operational speed without direct exposure to extreme temperatures, acting as a buffer between the driving mechanism and the turbine blades, thus protecting the turbine from thermal shock while still achieving the necessary mechanical work
2Reliability
If cold gases stored under high pressure in a dedicated tank are used to start the turbopump, then the turbine can be driven into rotation without thermal shock, but the device becomes heavy and bulky
Solution Approach 1:
The patent makes the turbine engine's compressed air system multi-functional by using it both for its primary purpose (powering the turbine engine) and as a starting mechanism for the turbopump. The compressed air taken from the turbine engine's compressor serves dual purposes: maintaining engine operation and providing controlled heating/acceleration of the turbopump turbine, thereby eliminating the need for a separate dedicated cold gas storage tank and reducing overall system mass
Solution Approach 2:
The turbine engine serves itself by using its own compressed air output to start its associated turbopump system. The compressed air generated during normal turbine engine operation is diverted to accelerate the turbopump turbine, allowing the system to self-start without requiring external heavy storage tanks or separate starting systems, thus reducing overall vehicle mass while protecting the turbine from thermal shock
3Power
If hot gases at high temperature are used to start the turbopump, then the turbine achieves sufficient energy for rotation, but the equipment requires frequent maintenance and replacement between flights
Solution Approach 1:
The patent applies preliminary action by first introducing compressed air at moderate temperature (600°C maximum) to gradually heat the turbine before introducing hotter combustion gases. This preparatory heating step prevents thermal shock when the turbine later operates with high-temperature rocket propellant combustion gases, thereby extending turbine lifespan while achieving the required rotation speed for pump operation
Solution Approach 2:
The patent uses compressed air as an intermediary substance to transfer energy to the turbine in a controlled manner. This intermediary medium allows the turbine to be accelerated to operational speed without direct exposure to extreme temperatures, acting as a buffer between the driving mechanism and the turbine blades, thus protecting the turbine from thermal shock while still achieving the necessary mechanical work
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution reduces thermal stress on turbopumps, maintains a compact and lightweight system, and extends equipment lifespan by gradually heating the turbines with compressed air at approximately 600°C, improving start-up reliability and reducing maintenance costs.
Implementation Method 1
a starting pneumatic supply of a turbine of the turbopump by a circuit for injecting compressed air taken by means of a tapping on a compressor stage of the turbine engine
Implementation Method 2
a combustion chamber of a gas generator for driving the turbine of the turbopump in rotation, said chamber being in the operating phase of the rocket engine supplied with liquid propellant
Implementation Method 3
The device comprises a combustion chamber of a gas generator for driving the turbine of the turbopump in rotation, said chamber being in the operating phase of the rocket engine supplied with liquid propellant
Data Source
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AI summary
The subject of the invention is a device for starting a turbopump (1) of a rocket motor (2) of an aircraft comprising a turbine engine for propelling the aircraft and a rocket motor, which comprises a pneumatic supply of compressed air to a turbine (1a) of the turbopump, this compressed air being tapped from a tapping (4) on a compressor stage (6a) of the aircraft propulsion turbine engine (5) upstream of the combustion chamber (7) of said turbine engine. It applies notably to an aircraft of the space airplane type.