Propulsion Heat Management Using Two-Phase Coolant
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Solution Overview
Problem
Propulsion systems face challenges in efficiently managing heat removal due to increasing heat loads from larger rotating machines and components, such as turbofan engines, which require more effective cooling methods to prevent overheating and optimize performance.
Innovation Solution
An anti-icing system incorporating a heat management system with a fluid flowpath that utilizes a heat exchanger at the nacelle inlet leading edge and extends through non-rotating members to transfer heat from the electric machine to air, including a diverter valve to adjust fluid flow and a two-phase coolant for enhanced heat transfer, allowing for efficient heat rejection and de-icing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional single-phase cooling systems are used, then the system structure is simple, but the heat removal efficiency is insufficient for larger rotating machines with higher heat loads
Solution Approach 1:
The patent transitions from single-phase coolant to two-phase coolant (liquid-vapor mixture), fundamentally changing the thermal state parameter. This phase change enables latent heat absorption, dramatically increasing heat removal capacity per unit mass of coolant without proportionally increasing system complexity
Solution Approach 2:
The system deliberately utilizes phase transition of the coolant from liquid to vapor and back. The two-phase coolant absorbs heat through evaporation in the heat exchanger and condenses in the condenser, providing high-efficiency heat transfer that addresses the insufficient heat removal of conventional single-phase systems
2Temperature
If heat is removed from the electric machine, then the electric machine temperature is controlled, but the available energy for thrust generation is reduced
Solution Approach 1:
The patent converts the waste heat from the electric machine (harmful factor causing overheating) into a useful resource for thrust generation. The heated air from the heat exchanger is directed to the nacelle inlet leading edge for anti-icing and to the propeller for enhanced thrust, transforming thermal waste into operational benefit
Solution Approach 2:
The cooling system serves multiple functions simultaneously: (1) cooling the electric machine, (2) providing anti-icing for the nacelle inlet leading edge, and (3) generating additional thrust through heated propeller airflow. This multi-functionality reduces net energy loss by making the heat removal process productive
3Use of energy by moving object
If a two-phase coolant system is implemented, then heat transfer efficiency is enhanced, but the system control complexity increases
Solution Approach 1:
The patent introduces a heat exchanger as an intermediary device that manages the two-phase coolant systematically. The heat exchanger provides controlled heat transfer surfaces where phase change occurs, and includes provisions for condensate drainage and air venting, simplifying the management of two-phase flow dynamics
Solution Approach 2:
The system incorporates a controller that monitors operational parameters and adjusts the two-phase coolant system accordingly. The controller manages the balance between liquid and vapor phases, regulates flow rates, and coordinates with the diverter valve to maintain optimal heat transfer efficiency under varying operating conditions
4Reliability
If more fluid is directed to the heat exchanger for de-icing, then the anti-icing effectiveness is improved, but the cooling capacity of the electric machine is reduced
Solution Approach 1:
The patent employs a dynamically adjustable diverter valve that can vary the fluid distribution ratio between the heat exchanger and the electric machine cooling path. This dynamic control allows the system to adapt to changing conditions, optimizing the balance between anti-icing requirements and electric machine cooling needs in real-time
Solution Approach 2:
The system proactively manages heat distribution before critical conditions develop. The controller anticipates heating requirements and adjusts fluid flow accordingly, preventing both ice formation on the nacelle and overheating of the electric machine by maintaining optimal thermal balance in advance
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
This solution effectively manages heat loads by transferring heat from the electric machine to air, optimizing de-icing and thrust generation while preventing overheating, and is applicable to various propulsion systems including turbofan engines.
Implementation Method 1
a heat exchanger positioned at the inlet leading edge of the nacelle... to effect heat transfer from the fluid to air passing around the inlet leading edge of the nacelle
Implementation Method 2
a first member heat exchanger disposed in the first member cavity to effect heat transfer from the fluid to air flowing around the first member
Implementation Method 3
the fluid conveyed in the fluid flowpath is a two-phase coolant
Implementation Method 4
to effect heat transfer from the electric machine to the fluid
Data Source
AI summary
Systems and methods of heat management of turbine engines including turbofans, turboprops and turboshafts and fan driven propulsion systems. The propulsion system may comprise a fan, nacelle, an electrical or mechanical heat source and a cooling system consisting of heat exchangers in the fan duct and on the nacelle and coolant pumps. The heat source can be a motor or a generator or turbine machinery or accessories rotationally coupled to rotating shafts. The heat management system transfers heat to the air in the fan flow path to provide additional fan thrust. The heat management system also transfers heat to structural members in the gas flow path that require anti-icing.