Capillary Pumped Rail Vehicle Power Converter Cooling

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Railway vehicle electric power converters require bulky and maintenance-intensive cooling systems due to mechanical pumps, leading to increased size and operational costs.

Innovation Solution

A capillary pumped cooling circuit using a two-phase heat transfer fluid that circulates through capillary evaporators, eliminating the need for mechanical pumps and reducing the size and maintenance requirements of the cooling system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If mechanical pumps are used to circulate heat transfer fluid in cooling loops, then the cooling system can effectively remove heat from electromagnetic components, but the size of the electric power converter increases and maintenance requirements increase

Engineering Contradiction:
Improveheat removal efficiencyVSAvoidcooling system size and maintenance
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent replaces mechanical pumps with capillary evaporators that utilize capillary action and phase change (evaporation/condensation) to circulate the heat transfer fluid. This substitution eliminates moving parts while maintaining effective heat removal through passive thermodynamic cycles, directly resolving the contradiction between heat removal efficiency and device complexity

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

Solution Approach 2:

The invention employs phase transitions of the heat transfer fluid (liquid to vapor in evaporators, vapor to liquid in condensers) to drive the cooling cycle. The phase change enables heat absorption and release while the resulting pressure differentials drive fluid circulation without mechanical pumps, solving both the heat removal requirement and the mechanical complexity issue

Inventive Principle:
Principle #36Phase transitions

2Temperature

If mechanical pumps are installed in cooling loops for electromagnetic components, then adequate cooling is achieved, but the electric power converter occupies more space

Engineering Contradiction:
Improvecooling performanceVSAvoidconverter size
Core Design Contradiction:
TemperatureVSVolume of moving object

Solution Approach 1:

By replacing mechanical pumps with capillary evaporators that use surface tension and phase change for fluid circulation, the patent eliminates the need for pump housings, drive mechanisms, and associated mounting structures. This significantly reduces the volume occupied by the cooling system within the converter while maintaining adequate cooling performance

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

Solution Approach 2:

The capillary evaporators utilize thin-walled structures and capillary channels that require minimal space compared to mechanical pump assemblies. The compact heat exchanger surfaces and integrated capillary wicks allow the cooling system to be space-efficient while achieving the required heat transfer performance

Inventive Principle:
Principle #30Flexible shells and thin films

3Temperature

If mechanical pumps are used in cooling circuits, then heat transfer fluid circulation is ensured, but maintenance costs increase

Engineering Contradiction:
Improveheat dissipation efficiencyVSAvoidmaintenance requirements and costs
Core Design Contradiction:
TemperatureVSEase of repair

Solution Approach 1:

The patent replaces mechanical pumps with passive capillary evaporators that have no moving parts, seals, or mechanical wear components. This eliminates the need for pump maintenance, seal replacement, and mechanical repairs, directly reducing maintenance costs and improving ease of repair while maintaining effective heat dissipation through capillary-driven phase change cycles

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

Solution Approach 2:

The capillary evaporators are self-regulating systems that automatically adjust fluid circulation based on thermal conditions. The capillary action and phase change processes occur without external control or mechanical intervention, making the system self-maintaining and eliminating the need for routine pump maintenance, thereby reducing operational costs

Inventive Principle:
Principle #25Self-service

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 reduces the size of the electric power converter and lowers maintenance costs by utilizing capillary evaporators to circulate the heat transfer fluid, ensuring efficient heat dissipation without mechanical pumps, thus improving thermal performance and operational efficiency.

Implementation Method 1

the circulation means comprise at least one capillary evaporator, through which the heat transfer fluid passes

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

the heat transfer fluid circulating in the cooling loop under the effect of the pressure generated at the liquid / vapor interface in the or each capillary evaporator

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 3

a second heat exchanger suitable for removing the heat from the heat transfer fluid out of the cooling circuit

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Data Source

PatentEP2782435B1Electric power converter for a rail vehicle
Publication Date: 2017.07.12 ALSTOM TRANSPORT TECH SAS
  • EP2782435B1 patent drawingFigure 1
  • EP2782435B1 patent drawingFigure 2

AI summary

The converter has a fluidic communicating unit (29) for fluidic connection of a heat exchanger (27) with another heat exchanger (28). A circulation unit (59) circulates a coolant in a cooling loop (26). A circuit coolant (14) is cools a heat source element. The circulation unit includes capillary evaporators (60A-60D) that are crossed by the coolant and located against the heat source element, where the coolant circulates in the cooling loop under effect of pressure generated at a level of a vapor/liquid interface in each capillary evaporator.