Motor Vehicle Heat Exchanger Flow Resistance Design
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Solution Overview
Problem
Heat exchangers for motor vehicles face challenges in managing significant temperature differences within limited installation space while maintaining low pressure drop and preventing condensation and deposit formation, with U-flow designs often resulting in higher flow resistance for a given cooling capacity and volume.
Innovation Solution
The heat exchanger optimizes flow resistance by designing the first and second flow paths with different resistances, where the first path has lower resistance and higher temperature differences, and the second path has greater resistance and turbulence-generating features like dimples or winglets to enhance heat transfer, while using materials like aluminum or stainless steel for the flow paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If U-flow design is used to reduce installation space, then compact connection area and short design are achieved, but flow resistance increases for a given cooling capacity
Solution Approach 1:
The patent applies different flow resistance characteristics to different flow paths based on their local thermal conditions. The first flow path (hotter fluid) has lower flow resistance with fewer or no turbulence-generating elements, while the second flow path (cooler fluid) has higher flow resistance with more turbulence-generating elements. This local differentiation optimizes heat transfer where needed while minimizing pressure losses overall.
Solution Approach 2:
The patent changes the flow resistance parameter along the flow path by varying the density and configuration of turbulence-generating elements. The first flow path has lower turbulence intensity and flow resistance, while the second flow path has higher turbulence intensity and flow resistance. This parameter variation allows optimization of both heat transfer efficiency and pressure drop characteristics.
2Productivity
If turbulence-generating means are added to increase heat transfer, then heat exchanger performance improves, but pressure drop increases
Solution Approach 1:
Turbulence-generating means are selectively applied to specific flow paths based on local heat transfer requirements. The second flow path, which handles cooler fluid with smaller temperature differences, receives more turbulence-generating elements to enhance heat transfer. The first flow path, handling hotter fluid with larger temperature differences, requires less turbulence enhancement. This local differentiation improves overall heat transfer efficiency while minimizing unnecessary pressure losses.
Solution Approach 2:
The patent applies turbulence-generating means partially rather than uniformly across all flow paths. By concentrating turbulence-enhancing elements in the second flow path where they are most needed, the patent achieves sufficient heat transfer enhancement without the excessive pressure drop that would result from applying turbulence-generating means to all flow paths equally.
3Stress or pressure
If flow resistance is reduced to lower pressure drop, then pressure losses decrease, but heat transfer efficiency may be compromised
Solution Approach 1:
The patent optimizes flow resistance locally in each flow path according to its specific thermal conditions. The first flow path maintains lower flow resistance to minimize pressure losses on the hot fluid side where large temperature differences already provide good heat transfer. The second flow path accepts higher flow resistance to enhance heat transfer on the cool fluid side where temperature differences are smaller and heat transfer is less efficient without turbulence enhancement.
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 achieves improved heat exchanger performance with reduced overall pressure drop and enhanced heat transfer, optimizing cooling efficiency and preventing deposit formation by adjusting flow resistances and turbulence in each path.
Implementation Method 1
the cooling of the fluid that has already taken place in the first flow path is taken into account when it enters the second flow path
Implementation Method 2
a particularly large temperature difference of typically several 100 °C is achieved with fluid cooling
Implementation Method 3
there is advantageously a greater flow resistance, in particular a greater proportion of turbulent flows, in the second flow path in order to achieve sufficient heat transfer
Data Source
Figure 1
Figure 2~4
AI summary
The invention relates to a heat exchanger for a motor vehicle, comprising a first flow path (1), a deflection region (13) located downstream of the first flow path (1) and a second flow path (2) that is located downstream of the deflection region (13). The first and second flow paths (1, 2) can be traversed by a fluid to be cooled and can be surrounded by a coolant to dissipate heat. The second flow path (2) has a flow resistance that differs from that of the first flow path (1).