Power Electronics Heat Exchanger with Graded Flow Constrictions
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Solution Overview
Problem
Existing heat exchangers for power electronic devices fail to maintain optimal temperatures under varying load conditions, leading to inefficiency and reliability issues due to ineffective thermal integration.
Innovation Solution
A heat exchanger design featuring a pair of metal plates with connected recesses forming a fluid circuit, including an inlet, outlet, and flowpaths with varying hydraulic diameters and flow constrictions, optimized for vertical operation to enhance refrigerant flow and thermal management, which includes a configuration where the ratio of the hydraulic diameter of the flow constriction to the fluid passage increases with distance from the inlet, and the use of flow constrictions to manage flow resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional heat exchanger designs are used, then the structure is simple, but the temperature control for power electronic devices is insufficient under varying load conditions
Solution Approach 1:
The heat exchanger employs flow constrictions at specific locations within the flow paths to create localized high-heat-transfer zones. These constrictions increase fluid velocity and turbulence locally, enhancing heat transfer coefficients where needed most, while maintaining simpler structures in other areas. This localized enhancement allows effective temperature control without requiring complex overall redesign.
Solution Approach 2:
The heat exchanger design incorporates variable flow path characteristics with constrictions that dynamically adapt to different operating conditions. The flow constrictions create varying flow rates and velocities through different sections of the heat exchanger, allowing the system to maintain effective thermal management under varying load conditions without requiring active control mechanisms.
2Productivity
If uniform flow paths are used, then the manufacturing is simple, but the flow rate distribution is uneven leading to poor thermal management
Solution Approach 1:
Flow constrictions are strategically positioned within the flow paths to create localized regions of increased fluid velocity and enhanced heat transfer. These constrictions are not uniformly distributed but are placed where thermal management is most critical, allowing uneven flow rate distribution that optimizes thermal performance while maintaining relatively simple manufacturing processes.
Solution Approach 2:
The heat exchanger design varies the hydraulic diameter and flow resistance parameters along different flow paths by incorporating flow constrictions. This creates deliberately non-uniform flow rate distributions that optimize heat transfer efficiency, with higher velocities in regions requiring greater thermal management and lower velocities in regions with lower thermal loads.
3Temperature
If flow constrictions are added to enhance heat transfer, then the temperature control improves, but the pressure drop increases
Solution Approach 1:
Flow constrictions are implemented as localized features rather than along the entire flow path length. This creates brief regions of high velocity and enhanced heat transfer followed by recovery sections where pressure can be regained. The localized nature of these constrictions minimizes overall pressure drop while maintaining effective temperature control in critical zones.
Solution Approach 2:
The flow constrictions are designed to provide just sufficient flow resistance enhancement to achieve the required heat transfer performance without excessive pressure drop. The constriction dimensions and lengths are optimized to deliver the minimum necessary flow control for effective thermal management, avoiding over-constriction that would unnecessarily increase 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
This design effectively maintains optimal temperatures for power electronic devices by reducing flow rate standard deviation and flow differences between passages, improving thermal integration and system efficiency.
Implementation Method 1
a heat exchanger configured to cool power electronic devices
Implementation Method 2
a refrigerant flowing through the fluid circuit
Implementation Method 3
one or more of the plurality of flowpaths comprise a fluid passage and a flow constriction, and wherein a ratio of the hydraulic diameter of the flow constriction to the hydraulic diameter of the fluid passage increases with increasing distance from the inlet
Data Source
AI summary
A heat exchanger comprising a pair of metal plates joined along corresponding mating surfaces, wherein at least one of the metal plates comprises a plurality of connected recesses which form a fluid circuit between the plates when the plates are joined, wherein the fluid circuit comprises an inlet, an inlet manifold, an outlet, an outlet manifold, and a plurality of flowpaths extending between and fluidly connecting the inlet manifold and outlet manifold, and wherein one or more of the plurality of flowpaths comprise a fluid passage and a flow constriction and wherein a ratio of the hydraulic diameter of the flow constriction to the hydraulic diameter of the fluid passage increases with increasing distance from the inlet.