Generator Wedge Spray Cooling Heat Transfer
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Solution Overview
Problem
Conventional heat removal methods in generators, such as conduction cooling, are inefficient due to high thermal resistance and require high fluid flow, which is impractical for rotating high-powered machines, especially when trying to manage heat from copper components.
Innovation Solution
A spray cooling system that uses a manifold with 90-degree pipes and a spray delivery device to distribute a cooling fluid into the wedges of a generator rotor, achieving a higher heat transfer coefficient compared to conventional methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conduction cooling is used with fluid flow through rotor shaft or hollow wedges, then heat removal from copper is improved, but thermal resistance remains high requiring very high fluid flow
Solution Approach 1:
The invention changes the heat transfer mechanism from conduction to spray cooling, transforming the thermal interaction mode between cooling fluid and wedge. This parameter change enables effective heat removal at much lower fluid flow rates by creating direct liquid-gas phase contact with the hot copper surface, dramatically improving heat transfer coefficient without requiring high fluid quantities
Solution Approach 2:
The invention uses spray cooling technology where cooling fluid is atomized and sprayed directly onto the wedge-copper interface. This hydraulic approach creates fine droplets that maximize surface area contact and heat transfer efficiency, allowing effective cooling with minimal fluid consumption compared to conventional conduction cooling methods
2Temperature
If high fluid flow is used to achieve reasonable heat transfer coefficient for conduction cooling, then heat removal is improved, but it becomes impractical for high powered larger diameter and high speed machines
Solution Approach 1:
The invention fundamentally changes the heat transfer parameter from conduction-based to spray-based cooling, achieving heat transfer coefficients 10 times higher than conventional methods. This parameter transformation makes the system practical for high-powered rotating machines by eliminating the need for impractical high fluid flow rates while maintaining effective heat removal
Solution Approach 2:
The cooling system is segmented into multiple spray delivery devices positioned at different locations around the rotor circumference. Each spray device targets specific wedge regions, allowing distributed heat removal that is effective for large diameter rotors without requiring centralized high-volume fluid delivery systems
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 spray cooling method effectively increases the heat transfer coefficient from 200-300 W/m2C to 2000-3000 W/m2C, efficiently cooling high-powered generators with high current density designs.
Implementation Method 1
A spray cooling manifold comprises a manifold ferrule adapted to circumscribe a shaft of a rotating machine; a manifold pipe having a bend of about 90 degrees having a first end attached to the manifold ferrule and a second, opposite end; a cooling fluid channel running from an inside surface of the manifold ferrule to the second, opposite end of the manifold pipe; and a spray delivery device disposed at the second, opposite end of the manifold pipe
Implementation Method 2
the spray cooling method effectively increases the heat transfer coefficient from 200-300 W/m2C to 2000-3000 W/m2C
Data Source
AI summary
A wedge cooling apparatus and method for cooling a rotating machine, such as a generator, disperses a spray of cooling fluid into the wedges of the generator. The spray cooling method results in a high heat transfer coefficient of about 2000-3000 W/m2C as opposed to conventional conduction cooling, which has a heat transfer coefficient of about 200-300 W/m2C. The apparatus and method of the present invention efficiently removes heat from high powered, high current density designed generators.