Refrigeration Ejector Layout for Gas-Liquid Separation and Oil Return
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Solution Overview
Problem
Ejectors in refrigeration cycles face inefficiencies due to low heat load and reduced refrigerant pressure difference, leading to inadequate depressurization and pressurization, and the integration of a gas-liquid separation device poses challenges in ensuring proper oil return to the compressor, affecting compressor durability.
Innovation Solution
An ejector design with a swirling space, depressurizing space, suction passage, and pressurizing space, featuring a conical passage formation member and a gas-liquid separation space that utilizes centrifugal force for efficient separation and an oil return passage positioned to facilitate the flow of liquid-phase refrigerant mixed with oil to the compressor intake.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a two-stage nozzle is used to improve nozzle efficiency, then the COP is improved, but the refrigerant may not be sufficiently depressurized in the second nozzle under low heat load conditions
Solution Approach 1:
The ejector is divided into multiple functional sections: a first nozzle for initial depressurization, a second nozzle for further depressurization and mixing, and a diffuser portion for pressure recovery. This segmentation allows each section to perform its specific function optimally, ensuring sufficient depressurization even under varying heat load conditions.
Solution Approach 2:
The diffuser portion is arranged radially outward from the nozzle axis rather than axially, creating a two-dimensional pressure recovery path. This radial arrangement allows the diffuser to effectively pressurize the mixed refrigerant without increasing the axial length of the ejector, while still achieving sufficient pressure recovery.
2Stress or pressure
If the diffuser portion is arranged coaxially on the nozzle extension to pressurize refrigerant, then pressure increase is achieved, but the axial length of the ejector body becomes unnecessarily long
Solution Approach 1:
The diffuser portion is arranged radially outward from the nozzle axis rather than continuing axially. This radial arrangement allows the diffuser to effectively pressurize the mixed refrigerant without increasing the axial length of the ejector, while still achieving sufficient pressure recovery through the radial pressure gradient.
3Reliability
If a gas-liquid separation device is integrated into the ejector to separate refrigerant phases, then separation is achieved, but the oil return to the compressor becomes challenging
Solution Approach 1:
The oil return passage is designed as a separate, dedicated channel that extracts oil from the liquid-phase refrigerant in the gas-liquid separation chamber and delivers it directly to the compressor intake. This separate extraction path ensures reliable oil return independent of the refrigerant flow patterns in the separation chamber.
Solution Approach 2:
The gas-liquid separation chamber serves multiple functions: separating gas and liquid refrigerant phases, providing a collection point for oil-laden liquid refrigerant, and facilitating oil return to the compressor. This multi-functionality integrates the separation and oil return functions into a single chamber, simplifying the overall system.
4Loss of energy
If the diffuser spread angle is reduced to improve ejector efficiency, then energy conversion efficiency is improved, but the axial length increases
Solution Approach 1:
The diffuser portion is arranged radially outward from the nozzle axis rather than continuing axially. This radial arrangement allows the diffuser to effectively pressurize the mixed refrigerant without increasing the axial length of the ejector, while still achieving sufficient pressure recovery through the radial pressure gradient.
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 configuration enhances energy conversion efficiency in the nozzle and restricts axial dimension growth, ensuring effective gas-liquid separation and proper oil return, thereby improving the overall performance and durability of the refrigeration cycle.
Implementation Method 1
a gas-liquid separation space that separates the refrigerant flowing out of the diffuser passage into gas and liquid by utilizing centrifugal force
Implementation Method 2
a nozzle passage that depressurizes and jets the refrigerant flowing out of the swirling space
Implementation Method 3
a diffuser passage that pressurizes a mixture of the ejection refrigerant and the suction refrigerant
Data Source
AI summary
A body of an ejector includes a diffuser passage, in which an ejection refrigerant jetted from a nozzle passage and a suction refrigerant drawn from a suction passage are mixed together and pressurized by arranging a passage formation member, and a gas-liquid separation space, in which the refrigerant flowing out of the diffuser passage is separated into gas and liquid by the action of a centrifugal force. An inlet part of an oil return passage that is open in the gas-liquid separation space is arranged at a position closer to an outer peripheral side than to an axis center of the passage formation member.