Turbopump Speed Control via Secondary Flow Shedding
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Solution Overview
Problem
Existing rocket engine propellant supply systems struggle to achieve stable thrust at multiple levels, particularly for deorbiting satellite launchers, as they require complex and less reliable circuits to manage varying thrust requirements, and existing solutions either restrict maximum pressure or complicate the propellant supply.
Innovation Solution
A method involving a first propellant pumped, heated, and expanded in a turbine-driven pump system, with a secondary flow shed upstream of the turbine to control the power ratio and stabilize the turbopump speed, allowing for reduced thrust levels without additional circuit complexity, using a regenerative heat exchanger and bypass valves to manage turbine speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a bypass passage of the turbine is opened to obtain reduced thrust mode, then lower thrust levels are achieved, but the propellant supply circuits become more complicated
Solution Approach 1:
The propellant flow is segmented into a main flow that drives the turbine and a secondary flow that is diverted through a bypass valve. This segmentation allows independent control of turbine power and pump flow, enabling thrust variation without adding complex circuitry. The bypass valve creates a simple parallel path that divides the propellant stream, achieving adaptability through flow splitting rather than complex circuit reconfiguration.
Solution Approach 2:
The invention changes the flow rate parameter by diverting a portion of the propellant through the bypass valve. By adjusting the bypass valve opening, the ratio of main flow to secondary flow changes, which directly controls the turbine speed and consequently the pump output. This parameter change approach allows continuous thrust adjustment using a simple valve mechanism rather than complex circuit changes.
2Measurement precision
If the turbine and pump speed are reduced to achieve lower thrust, then deorbiting precision is improved, but the power balance between turbine and pump becomes unstable
Solution Approach 1:
The system establishes a feedback loop where the bypass valve adjusts the secondary flow based on the required thrust level, which in turn regulates the main flow to the turbine. This feedback mechanism ensures that the turbine generates exactly the power needed to drive the pump at the desired speed, maintaining stable power balance. The controlled shedding of secondary flow provides continuous adjustment capability that stabilizes the power relationship between turbine and pump across different operating points.
Solution Approach 2:
The invention introduces dynamic control through the bypass valve that can continuously adjust the flow split ratio. This dynamic adjustment capability allows the system to adapt to different thrust requirements while maintaining stable operation. The bypass mechanism provides a degrees-of-freedom that decouples the turbine power generation from the total pump flow requirement, enabling stable operation at various speed levels including low-speed deorbiting mode.
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
Enables stabilization of rocket engine thrust at lower levels than nominal, reducing turbopump speed and maintaining system reliability by controlling the power balance between the turbine and pump, allowing for precise thrust control without additional complications in the propellant supply circuits.
Implementation Method 1
the heat exchanger can in particular be a heat exchanger of the so-called regenerative type, that is to say heating the first propellant with heat generated in said combustion chamber. Thus the supply circuit is a circuit of the so-called expander type, using this heat transfer to the first propellant simultaneously to cool the walls of the combustion chamber and/or of the propulsion nozzle
Implementation Method 2
expanded, after said heating, in a first turbine actuating the first pump
Data Source
AI summary
The invention relates to the field of supplying jet engines, and in particular to a supply method which includes jettisoning a secondary flow of a first propellant downstream from a first pump (9a), but upstream from a first turbine (9b) actuated by the expansion of said same first propellant and actuating at least the first pump (9a). Said jettisoning is controlled so as to achieve a balance between the power generated by the first turbine (9b) and the power consumed by the first pump (9a), and thus to halt the increase in the speed of said first turbine (9b) and first pump (9a) at a predetermined speed that is lower than a nominal speed.