Scroll Compressor Flow Resistance for Lower Back-Pressure Pulsation
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Solution Overview
Problem
Existing scroll compressors face challenges in maintaining efficient operation under low load conditions due to increased refrigerant flow and pulsation pressure in the back pressure chamber, limited by machining constraints on reducing the area of the back pressure passage, which leads to increased dead volume and friction loss.
Innovation Solution
Incorporation of a flow resistance portion within the back pressure passage to minimize the cross-sectional area and reduce refrigerant flow, thereby reducing pressure pulsation and dead volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the area of the back pressure passage is reduced to lower pulsation pressure and reduce dead volume, then compression efficiency is improved, but machining characteristics limit further reduction
Solution Approach 1:
The back pressure passage is divided into multiple segments: the original passage and additional passages formed by grooves. This segmentation allows the total effective area to be reduced while maintaining manufacturability, as the grooves can be easily machined into the existing passage structure.
Solution Approach 2:
Grooves are added at specific locations within the back pressure passage to locally reduce the effective cross-sectional area. This local modification approach maintains ease of manufacture while achieving the goal of reducing overall passage area to lower dead volume and pulsation pressure.
2Volume of stationary object
If the area of the back pressure passage is reduced, then dead volume is reduced, but the amount of refrigerant flowing through the passage increases due to flow constraints
Solution Approach 1:
The grooves act as flow resistance elements that mediate between the reduced passage area and refrigerant flow. They create controlled resistance that manages the refrigerant flow rate, allowing the passage area to be reduced for lower dead volume while preventing excessive flow restriction that would increase pulsation pressure.
3Stress or pressure
If the back pressure passage area is minimized, then pressure pulsation is reduced, but friction loss increases due to smaller passage dimensions
Solution Approach 1:
The groove configuration allows for dynamic optimization of the passage characteristics. By adjusting the groove depth, width, and positioning, the effective passage area can be tuned to achieve the right balance between reducing pressure pulsation and minimizing friction loss, adapting to different operating conditions.
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 flow resistance portion effectively minimizes refrigerant flow and pressure pulsation, enhancing machining and assembly properties while improving compression efficiency and reducing friction loss.
Implementation Method 1
a flow resistance portion to reduce an amount of refrigerant flowing through the back pressure passage
Data Source
AI summary
A scroll compressor is provided that may include an orbiting scroll, a non-orbiting scroll, a back pressure chamber assembly, a back pressure passage, and a flow resistance portion. The back pressure passage may provide communication between a compression chamber and a back pressure chamber, and the flow resistance portion may be disposed at a middle portion of the back pressure passage to reduce an amount of refrigerant flowing through the back pressure passage. This may reduce a substantial cross-sectional area of the back pressure passage while improving machining of the back pressure passage, thereby decreasing an amount of refrigerant flowing between the compression chamber and the back pressure chamber. Accordingly, pressure pulsation in the back pressure chamber may be lowered and sealing stability between the orbiting scroll and the non-orbiting scroll may be enhanced, thereby improving compression performance.