Ship Pod Propulsion Motor Cooling via Closed Gas Circuit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current pod propulsion units face challenges with air cooling requirements for high-power electric motors, leading to increased drag and structural complexity, as well as issues with coal dust and oil contamination due to direct seawater cooling inefficiencies, necessitating the use of expensive synchronous motors.
Innovation Solution
A closed cooling gas circuit with a gas-liquid heat exchanger and fan system, where the stator is snug-fitted in a tubular section of the motor gondola, allowing for efficient thermal energy exchange between gas and liquid, reducing the need for direct seawater cooling and minimizing contamination risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If air cooling is used for high-power electric motors, then cooling effectiveness is improved, but the diameter of motor housing increases and structural complexity increases
Solution Approach 1:
The patent combines the cooling air ducts with the motor housing structure itself, where the housing walls serve as both structural support and cooling pathways. This integration eliminates separate cooling duct components and reduces overall structural complexity while maintaining effective air cooling of the high-power electric motor.
2Temperature
If air cooling is used for high-power electric motors, then cooling effectiveness is improved, but drag of the hull increases
Solution Approach 1:
The cooling air ducts are integrated into the motor housing structure, allowing the housing to serve dual purposes: providing structural support and facilitating cooling airflow. This eliminates the need for additional external cooling structures that would increase the overall diameter and create more drag on the hull, while still achieving effective motor cooling.
3Temperature
If direct sea water cooling is used, then cooling effectiveness is improved, but coal dust and oil contamination occurs
Solution Approach 1:
The patent uses a closed-loop cooling system with a heat exchanger as an intermediary between the motor and the sea water. The cooling medium circulates in a sealed system, preventing direct contact between sea water (and associated contaminants like coal dust and oil) and the motor components, while still achieving effective heat removal through the heat exchanger.
4Temperature
If synchronous electric motors with permanent-magnet excitation are used, then cooling effectiveness is improved, but cost increases
Solution Approach 1:
The patent employs a closed-loop cooling system with heat exchanger as an intermediary, enabling effective cooling without requiring expensive synchronous motors with permanent-magnet excitation. This approach allows the use of more cost-effective motor designs while achieving the necessary thermal management through the sealed cooling circuit.
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 solution enhances cooling efficiency, reduces drag, and prevents coal dust and oil contamination, allowing for effective cooling without the need for expensive synchronous motors, thereby improving hydrodynamic efficiency and structural simplicity.
Implementation Method 1
The pod propulsion unit may comprise a gas-liquid heat exchanger arranged in the closed cooling gas circuit between the feeding duct and the return duct for exchanging thermal energy between gas flowing in the closed cooling gas circuit and liquid circulating in a cooling liquid circuit
Implementation Method 2
The pod propulsion unit comprises a fan for circulating gas such as air in the closed cooling gas circuit
Implementation Method 3
liquid circulating in a cooling liquid circuit
Data Source
AI summary
The invention relates to a pod propulsion unit of a ship. The pod propulsion unit comprises a pod housing arranged at least partly below a hull of the ship, an electric propeller motor within a motor gondola of the pod housing, an annular gap between a rotor and a stator of the electric propeller motor, and gas channels extending through the rotor, a closed cooling gas circuit, and a fan for circulating gas in the closed cooling gas circuit. The closed cooling gas circuit comprising a feeding duct extending between the return duct and the first motor end face of the electrical propeller motor, and a return duct extending between the feeding duct and the opposite second motor end face of the electrical propeller motor.