Actively Cooled Heat Shield With Turbine-Driven Coolant Recirculation
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Solution Overview
Problem
Existing heat management solutions for vehicles traveling at hypersonic speeds, such as rockets and space re-entry vehicles, are not robust, controllable, or suited for long-term reusability, leading to significant challenges in reusing upper stage rockets due to harsh re-entry environments and structural mass requirements.
Innovation Solution
An actively-cooled heat shield system incorporating a heat shield, tank, pump, heat exchanger, and turbine that converts heat into energy to drive a liquid coolant pump, using a closed-loop system to maintain thermal protection and power the pump.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional heat management solutions (ablative materials, high-temperature materials, transpiration cooling) are used, then thermal protection is provided, but the system lacks robustness, controllability, or reusability
Solution Approach 1:
The patent implements a closed-loop feedback system where temperature sensors monitor the thermal state of the heat shield and adjust the coolant flow rate accordingly. This feedback mechanism provides active controllability and adaptability, allowing the system to respond to varying thermal loads during re-entry while maintaining robust thermal protection and enabling repeated use.
Solution Approach 2:
The system uses the vehicle's own propulsion system components (pump and heat exchanger) to provide cooling, making the cooling system self-contained and integrated with the vehicle's existing infrastructure. This self-service approach enhances robustness by eliminating external dependencies and improves reusability by using durable, reusable components rather than consumable materials.
2Reliability
If robust thermal protection is implemented for reusable vehicles, then structural mass must be increased, but this reduces payload capacity
Solution Approach 1:
The patent replaces passive mechanical thermal protection systems (thick ablative materials or ceramic tiles) with an active fluid cooling system. This substitution allows for thinner heat shield structures since the cooling function is performed by the circulating coolant rather than by material thickness, thereby reducing structural mass while maintaining thermal protection capability for reusable vehicles.
Solution Approach 2:
The system changes the thermal management approach from passive material-based protection to active parameter-controlled cooling by adjusting coolant flow rate, pressure, and temperature. This parameter-based control enables adaptive thermal protection with reduced mass, as the cooling effectiveness is controlled by operational parameters rather than fixed material properties.
3Ease of operation
If active cooling systems are implemented, then thermal protection and controllability are improved, but device complexity increases
Solution Approach 1:
The patent integrates the cooling system with the vehicle's existing propulsion system by using the same pump, heat exchanger, and coolant infrastructure for both propulsion and thermal management functions. This multi-functionality approach reduces overall system complexity despite the active cooling capabilities, as components serve dual purposes rather than requiring separate dedicated systems.
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 system effectively maintains thermal protection and sustains operation by converting heat into energy to power the pump, enabling reusable vehicles to withstand high temperatures and reduce structural mass, thus enhancing reusability and efficiency.
Implementation Method 1
The heat exchanger is configured to receive the pressurized coolant from the pump, transfer heat from the heat shield to the pressurized coolant to generate a heated fluid
Implementation Method 2
The inlet is configured to receive the heated fluid output from the heat exchanger. The shaft is coupled to the pump and includes turbine blades mounted thereon. The shaft is configured to rotate and thereby power the pump when the heated fluid received from the heat exchanger acts on the turbine blades
Data Source
AI summary
A vehicle includes: a heat shield configured to define a windward side of the vehicle during travel of the vehicle in an atmospheric re-entry trajectory; a tank configured to store a coolant; a pump configured to receive the coolant from the tank and output a pressurized coolant; a heat exchanger configured to receive the pressurized coolant from the pump, transfer heat from the heat shield to the pressurized coolant to generate a heated fluid, and output the heated fluid; and a turbine configured to receive the heated fluid output from the heat exchanger, extract energy from the heated fluid, and power the pump using energy extracted from the heated fluid. A related method is also disclosed.