Transformer Radiator Boundary-Layer Breakup for Better Cooling

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Solution Overview

Problem

The efficiency of radiators used for cooling power transformers is limited by the formation of a temperature profile in air flow between radiator elements, where warm air near the elements hinders heat transfer, and increasing surface area or spacing is constrained by space and hydraulic resistance considerations.

Innovation Solution

Incorporating devices such as rods, wires, or plates between radiator elements to break up the boundary layer, which can be retrofitted to existing radiators, to deflect air and enhance heat transfer without significantly increasing air resistance, thereby improving cooling performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the surface area of radiator sections is increased to improve heat transfer, then heat transfer efficiency is improved, but hydraulic resistance increases and space requirements increase

Engineering Contradiction:
Improvecoolant temperature reductionVSAvoidradiator surface area
Core Design Contradiction:
TemperatureVSQuantity of substance

Solution Approach 1:

The invention changes the thermal boundary conditions by introducing surface roughness elements that modify the boundary layer characteristics. This allows enhanced heat transfer coefficients without proportionally increasing the radiator surface area, thereby resolving the contradiction between heat transfer efficiency and surface area quantity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention applies local modifications to the radiator surface through roughness elements at specific locations where boundary layers form. This localized approach enhances heat transfer at critical positions without requiring uniform expansion of the entire radiator surface area.

Inventive Principle:
Principle #3Local quality

2Temperature

If the spacing between radiator sections is increased to improve heat transfer, then heat transfer efficiency is improved, but the radiator volume and space requirements increase

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidradiator volume
Core Design Contradiction:
TemperatureVSVolume of stationary object

Solution Approach 1:

The invention modifies the boundary layer parameters through surface roughness elements, enabling enhanced heat transfer within the existing spacing between radiator sections. This eliminates the need to increase radiator volume or spacing to achieve improved heat transfer efficiency.

Inventive Principle:
Principle #35Parameter changes

3Temperature

If boundary layer dissolving devices are added to enhance heat transfer, then heat transfer efficiency is improved, but device complexity increases

Engineering Contradiction:
Improveheat transfer from radiator to airVSAvoidradiator structure complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The invention implements boundary layer dissolution through simple surface roughness elements rather than complex active devices. This approach enhances heat transfer efficiency while maintaining minimal structural complexity, as the roughness elements are passive geometric features integrated into the radiator surface.

Inventive Principle:
Principle #35Parameter changes

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 homogenizes air temperature within the flow channel, increasing heat transfer from the radiator to the air, allowing for improved cooling performance without altering hydraulic properties or requiring redesign, and can be applied to various types of radiators.

Implementation Method 1

a device for breaking up the boundary layer of that air flow which flows between two radiator elements

Methodology Applied
Scientific EffectBoundary layer: Boundary Layer

Implementation Method 2

heat transfer from the radiator element to the air can be increased

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Data Source

PatentEP3812677B1Radiator for cooling a transformer or a choke
Publication Date: 2023.08.30 SIEMENS ENERGY GLOBAL GMBH & CO KG
  • EP3812677B1 patent drawingFigure 1
  • EP3812677B1 patent drawingFigure 2
  • EP3812677B1 patent drawingFigure 3

AI summary

The invention relates to a radiator (6) for cooling a transformer (1), preferably a power transformer, or an inductor. The radiator (6) comprises several radiator elements (5) arranged parallel to one another, through which a coolant flows. It is proposed that at least one device for dissolving the boundary layer of the airflow between the radiator elements (5) is provided between two radiator elements (5). These devices, such as rods (8) and/or wires (9) and/or plates (14), homogenize the air temperature in the flow channel formed between two adjacent radiator elements (5).