Centrifugal Compressor Oil Passage Layout for Pressure Relief
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Solution Overview
Problem
Centrifugal compressors face issues with pressure increase in the speed increaser chamber and oil leakage due to the friction and seizure of the high-speed shaft, leading to inefficient operation and potential power loss in fuel cell vehicles.
Innovation Solution
A centrifugal compressor design with an oil passage system that separates oil and air layers using gravity and horizontal passages, incorporating a pressure relief passage to manage pressure and prevent oil leakage, while maintaining adequate lubrication for seals and bearings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If a seal is provided between the high-speed shaft and shaft insertion hole to prevent oil leakage, then oil leakage is reduced, but friction and seizure increase leading to potential power loss
Solution Approach 1:
A groove is provided in the shaft insertion hole to store oil, acting as an intermediary reservoir. This allows oil to be readily available for lubrication at the seal interface without requiring excessive oil supply that would increase leakage risk. The groove mediates between the need for lubrication and the need to prevent oil leakage into the impeller chamber.
2Productivity
If the impeller rotates at low speed or the compressor is not running, then gas compression is reduced, but oil leaks from the speed increaser chamber to the impeller chamber through the shaft insertion hole
Solution Approach 1:
The groove in the shaft insertion hole is pre-filled with oil before operation begins. This preliminary oil storage ensures that lubrication is immediately available when the system starts up or operates at low speeds, preventing oil leakage through the seal interface during these critical transition periods when pressure differentials may cause leakage.
3Stress or pressure
If gas leaks from the impeller chamber to the speed increaser chamber, then pressure in the speed increaser chamber increases, but this increases the pressure differential that drives oil leakage
Solution Approach 1:
The groove structure converts the harmful pressure differential into a beneficial effect. When pressure in the speed increaser chamber increases due to gas leakage, the stored oil in the groove is pressed against the seal interface more effectively, enhancing the sealing action and preventing oil from leaking into the impeller chamber. The pressure that would normally drive leakage is instead used to maintain the oil seal.
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 design effectively limits pressure increases in the speed increaser chamber, reduces oil leakage, and maintains efficient operation by ensuring consistent lubrication, thereby enhancing the performance and power generation efficiency of fuel cell vehicles.
Implementation Method 1
When the oil passes through the third oil passage, fluid including the oil is separated into a gas layer and an oil layer
Data Source
AI summary
An oil passage of a centrifugal compressor includes a first oil passage that communicates with an oil pan and a speed increaser chamber to supply oil to a speed increaser and the seal. A second oil passage communicates with the speed increaser chamber. A third oil passage extends upward in a gravitational direction from an end of the second oil passage. A fourth oil passage extends in a horizontal direction and causes the oil pan and an end of the third oil passage to communicate with each other. A pressure relief passage that communicates with an outside is arranged in at least one of a portion of the fourth oil passage through which a gas layer passes and a portion of the oil pan in which the gas layer is stored.