Diffuser Integrated Heat Exchanger for Gas Turbine Pressure Loss Reduction
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Solution Overview
Problem
Introducing a heat exchanger into a gas turbine engine's flowpath leads to high pressure losses due to high velocities, which can outweigh efficiency gains and is challenging to incorporate into compact designs, especially when using prior art designs with diffusers that increase system length.
Innovation Solution
A heat exchanger apparatus with integral diffuser features, including diverging and converging flow channels and staggered fins that act as turning vanes, reducing flow velocity and pressure losses while maintaining compactness by continuously increasing the open flow area from the inlet to the belly of the heat exchanger.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a heat exchanger is introduced into a gas turbine engine flowpath, then heat transfer efficiency is improved, but pressure losses increase due to high velocities
Solution Approach 1:
The heat exchanger is divided into multiple flow passages separated by fins, allowing the flow to be segmented into smaller channels. This segmentation increases the surface area for heat transfer while maintaining lower velocities in each passage, reducing pressure losses compared to a single large passage.
Solution Approach 2:
The invention transitions from a two-dimensional planar heat exchanger to a three-dimensional configuration with fins extending into the flowpath. This adds a third dimension for heat transfer surface area, enabling efficient heat exchange without requiring high flow velocities that would cause excessive pressure losses.
2Loss of energy
If a diffuser is positioned upstream of the heat exchanger to reduce flow velocities, then pressure losses are avoided, but the overall length of the heat exchanger system increases
Solution Approach 1:
The diffuser function is merged with the heat exchanger inlet structure. The peripheral walls of the heat exchanger itself are configured to diverge and form a diffuser, eliminating the need for a separate upstream diffuser component. This integration reduces the overall system length while maintaining the pressure loss reduction benefits.
Solution Approach 2:
The peripheral walls of the heat exchanger serve multiple functions: they define the flow passages for heat transfer, acts as the diffuser structure to reduce velocities, and provide structural support. This multi-functionality eliminates the need for separate components and reduces system length.
3Use of energy by moving object
If fins are added to increase heat transfer surface area, then heat transfer efficiency improves, but flow area is reduced causing higher velocities and pressure losses
Solution Approach 1:
The fins are strategically positioned and dimensioned to provide adequate heat transfer surface area in specific regions without excessively blocking the flow path. The local fin geometry is optimized to balance heat transfer enhancement with flow passage maintenance, ensuring that heat transfer efficiency improves without causing excessive velocity increases or pressure losses.
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 achieves a balance of heat transfer efficiency with minimal pressure loss, enabling the use of heat exchangers in high-velocity flowpaths where prior designs were not feasible, such as in gas turbine engines, by diffusing the flow without substantial length increase.
Implementation Method 1
a flow channel which includes a diverging portion downstream of the inlet, in which a flow area is greater than a flow area at the inlet
Implementation Method 2
diffusing the flow without substantial length increase
Implementation Method 3
a heat transfer structure disposed within at least one of the fins
Implementation Method 4
heat exchanger apparatus having a diffuser integral thereto
Data Source
AI summary
A heat exchanger apparatus includes: spaced-apart peripheral walls extending between an inlet and an outlet, the peripheral walls collectively defining a flow channel which includes a diverging portion downstream of the inlet, in which a flow area is greater than a flow area at the inlet; a plurality of spaced-apart fins disposed in the flow channel, each of the fins having opposed side walls extending between an upstream leading edge and a downstream trailing edge, wherein the fins divide at least the diverging portion of the flow channel into a plurality of side-by-side flow passages; and a heat transfer structure disposed within at least one of the fins.