Transformer Oil-Air Heat Exchanger Cooling With Cross-Flow Jet

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Solution Overview

Problem

Conventional air-cooling methods for transformers using fans are noisy, complex, heavy, and inefficient, with non-uniform cooling patterns that fail to adequately cool all surfaces, leading to re-injection of hot oil into the transformer tank.

Innovation Solution

A cooling arrangement utilizing an impeller-motor device, fluid pipes, and a first fluid discharge device with a second fluid discharge device that applies a cross flow jet to destabilize and redistribute the fluid flow, enhancing cooling efficiency and uniformity across transformer surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional fans are used for air-cooling, then cooling power is sufficient, but noise level is high and structure is complex

Engineering Contradiction:
Improvenoise levelVSAvoidstructure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent replaces conventional mechanical fans with a bladeless fan system that uses fluid dynamics principles. An impeller generates a fluid jet that flows through a linear slot, creating a multiphase flow field that provides cooling without rotating blades, thereby eliminating fan noise and simplifying the mechanical structure.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention utilizes pneumatic principles by generating a controlled fluid jet through an impeller that flows through a linear slot. This creates a multiphase flow field where the fluid dynamics itself provides the cooling effect, replacing traditional mechanical fan propulsion with a pneumatic-hydraulic system.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Use of energy by moving object

If bladeless fan with linear slot is used, then power consumption is reduced, but cooling uniformity deteriorates

Engineering Contradiction:
Improvepower consumptionVSAvoidcooling uniformity
Core Design Contradiction:
Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The patent introduces a fluid disturbance device that dynamically modifies the fluid jet characteristics. By adding controlled disturbances to the fluid flow, the system creates more uniform distribution patterns across the cooling surface, compensating for the inherent non-uniformity of linear slot jet flows while maintaining low power consumption.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the parameters of the fluid flow by introducing disturbances that modify velocity distribution and flow patterns. This transforms the original non-uniform jet flow into a more uniform cooling field, achieving better cooling uniformity without significantly increasing power consumption.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If natural convection is used, then device complexity is reduced, but cooling efficiency is insufficient for high power transformers

Engineering Contradiction:
Improvecooling system complexityVSAvoidcooling efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent replaces natural convection with a controlled multiphase flow system that uses an impeller-generated fluid jet. This substitution provides forced cooling capability necessary for high power transformers while maintaining relatively simple device architecture through the use of fluid dynamics rather than complex mechanical assemblies.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 significantly reduces power consumption and noise levels while providing a powerful and uniform cooling effect, effectively enhancing the heat transfer coefficient and maintaining transformer operation efficiency.

Implementation Method 1

The at least one impeller-motor device (10) is adapted to supply the fluid to the inlet of the first fluid discharge device (12) via the at least one fluid pipe (11) and cause the fluid to flow through the at least one fluid outlet (13) of the first fluid discharge device (12) in a direction of the at least one OAEHE

Methodology Applied
Scientific EffectForced Convection: Forced Convection

Implementation Method 2

The cooling arrangement further comprises a second fluid discharge device (22) adapted to disturb the fluid that flows through the at least one fluid outlet (13) of the first fluid discharge device (12)

Methodology Applied
Scientific EffectTurbulence: Turbulence

Data Source

PatentEP4376033A1Cooling arrangement and method for cooling at least one oil-to-air external heat exchanger
Publication Date: 2024.05.29 HITACHI ENERGY LTD
  • EP4376033A1 patent drawingFigure 1
  • EP4376033A1 patent drawingFigure 2a~2b
  • EP4376033A1 patent drawingFigure 3

AI summary

A cooling arrangement (20) for cooling at least one OAEHE in a transformer. The cooling arrangement (20) comprises at least one impeller-motor device (10), at least one fluid pipe (11) and a first fluid discharge device (12). The first fluid discharge device (12) comprises a fluid inlet arranged to receive a fluid from the at least one fluid pipe (11), and at least one fluid outlet arranged to direct the fluid towards the OAEHE, wherein the at least one impeller-motor device (10) is adapted to supply the fluid to the inlet of the first fluid discharge device (12) via the at least one fluid pipe (11) and cause the fluid to flow through the at least one fluid outlet of the first fluid discharge device (12) in a direction of the at least one OAEHE. The cooling arrangement (20) further comprises a second fluid discharge device (22) adapted to disturb the fluid that flows through the at least one fluid outlet of the first fluid discharge device (12).