Interlocking Core Assembly for Cast Heat Exchanger Plates
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Solution Overview
Problem
Turbine engine heat exchangers face high thermal stresses due to increasing operational temperatures and pressures, which can exceed material and assembly joint capabilities, leading to unbalanced stress distribution and potential structural failures.
Innovation Solution
A method of forming a cast heat exchanger plate using interlocking core assemblies with hot and cold core plates, where a wax pattern is formed around the assembly, an external shell is created, and molten material is cured to produce a single-piece unitary cast plate with integrated fins and channels, reducing stress concentrations and enhancing thermal transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sheet metal plates and fins are brazed together to form heat exchanger, then thermal transfer efficiency is improved, but stress concentrations exceed material and joint capabilities leading to structural failure
Solution Approach 1:
The patent merges multiple separate components (plates and fins) into a single integrated cast structure. The core assembly combines hot core plates, cold core plates, and fin structures into one monolithic unit, eliminating brazed joints that are vulnerable to thermal stress. This integration resolves the contradiction by maintaining structural integrity while withstanding high stress concentrations through unified material continuity.
Solution Approach 2:
The patent employs composite construction by assembling multiple core plates with different thermal characteristics (hot core plates and cold core plates) into a unified cast structure. The differential thermal expansion between adjacent plates is accommodated through the cast integration, allowing the composite structure to resist thermal stresses that would otherwise cause failure in homogeneous or brazed constructions.
2Reliability
If operational temperatures and pressures are increased to improve engine efficiency, then thermal transfer performance is improved, but thermal stresses exceed material capabilities causing potential failures
Solution Approach 1:
The integration of all heat exchanger components into a single cast unit eliminates weak joints that would fail under high thermal stress. The unified structure allows thermal gradients to be distributed throughout the entire component rather than concentrating at brazed joints, enabling the heat exchanger to withstand higher operational temperatures and pressures.
Solution Approach 2:
The casting process enables the use of materials and geometries optimized for high-temperature service. The monolithic construction allows for controlled material selection and thermal gradient management, changing the thermal and mechanical parameters to withstand extreme operational conditions while maintaining efficient heat transfer.
3Duration of action of stationary object
If alternate construction techniques are used to reduce stress concentrations, then structural durability is improved, but manufacturing complexity and implementation feasibility deteriorate
Solution Approach 1:
The core assembly is pre-assembled with all internal features (passages, channels, fin structures) configured in their final positions before casting. This preliminary arrangement of components ensures proper alignment and integration, simplifying the subsequent casting process while achieving the complex integrated structure needed for stress resistance and durability.
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 provides a scalable, durable heat exchanger design that mitigates stress concentrations and improves thermal efficiency by creating a single-piece unitary cast plate with integrated fins and channels, enhancing the structural integrity and performance of turbine engine heat exchangers.
Implementation Method 1
The wax pattern is removed to form a space between the core assembly and the external shell
Implementation Method 2
The space is filled with a molten material and cures the molten material
Data Source
AI summary
A method of forming a cast heat exchanger plate includes forming at least one hot core plate defining internal features of a one piece heat exchanger plate and at least one first set of interlocking features. At least one cold core plate is formed defining external features of the heat exchanger plate and at least one second set of interlocking features. A core assembly is assembled wherein each hot core plate is directly interlocked to the at least one cold core plate. A wax pattern is formed with the core assembly. An external shell is formed over the wax pattern. The wax pattern is removed to form a space between the core assembly and the external shell. The space is filled with a molten material and cures the molten material. The external shell is removed. The core assembly is removed. A core assembly for a cast heat exchanger is also disclosed.