Swirl-Promoting Ejector Diffuser for Stable Low-Load Pressurization
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Solution Overview
Problem
Ejectors in refrigeration cycles face challenges in achieving high nozzle efficiency and pressurizing performance across varying load conditions without increasing the ejector's body size, particularly due to reduced refrigerant flow rates and pressure differences, which affect the efficiency of the diffuser passage and gas-liquid separation.
Innovation Solution
The ejector design incorporates a swirling space for refrigerant swirl generation, a conical passage formation member that increases in cross-sectional area, and a diffuser passage with an annular shape to promote swirling flow and restrict axial growth, combined with a swirling promotion part to maintain high energy conversion efficiency and pressurizing performance across load variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a two-stage nozzle configuration is used to improve nozzle efficiency, then the COP is improved, but at low load conditions the refrigerant pressure difference is reduced and most refrigerant is not sufficiently depressurized in the second nozzle
Solution Approach 1:
The patent employs a movable partition wall that can dynamically adjust the flow distribution between the first and second nozzles based on operating conditions. This dynamic adjustment allows the system to maintain optimal nozzle efficiency across varying load conditions, resolving the contradiction between high efficiency at design point and adaptability across all operating ranges.
Solution Approach 2:
The patent changes the flow distribution parameter by adjusting the partition wall position, thereby altering the refrigerant flow rates to each nozzle. This parameter adjustment enables the system to adapt to different load conditions while maintaining sufficient pressure difference and depressurization effectiveness in both nozzles.
2Loss of energy
If the diffuser portion spread angle is reduced to improve ejector efficiency, then pressurizing performance is improved, but the nozzle portion length in axial direction becomes longer
Solution Approach 1:
The patent introduces a radial flow component by arranging the diffuser portion to receive flow from multiple nozzles in different spatial directions. This dimensional change allows the diffuser to achieve sufficient pressurizing performance with a smaller axial length, as the flow paths utilize both radial and axial components rather than being purely axial.
Solution Approach 2:
The patent nests multiple nozzles and their associated diffuser passages within a compact three-dimensional arrangement. The diffuser portion is positioned to efficiently collect and pressurize flow from multiple nozzle outlets in a nested configuration, achieving high ejector efficiency without requiring excessive axial length.
3Loss of energy
If a two-stage nozzle is used to depressurize refrigerant, then nozzle efficiency is improved, but the ejector body becomes unnecessarily longer in normal load conditions
Solution Approach 1:
The movable partition wall enables dynamic reconfiguration of the two-stage nozzle system. Under normal load conditions, the partition can be positioned to optimize flow distribution while maintaining a more compact axial arrangement, thereby preserving nozzle efficiency benefits without the penalty of excessive body length.
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 nozzle efficiency and pressurizing performance, maintaining high energy conversion efficiency and reducing the risk of refrigerant under-pressurization and gas-liquid separation performance degradation, even at low load conditions, without increasing the ejector's size.
Implementation Method 1
a nozzle portion that depressurizes refrigerant, draws a gas-phase refrigerant which has flowed out of an evaporator due to a suction action of an ejected refrigerant ejected from the nozzle portion
Implementation Method 2
mixes the ejected refrigerant with the suction refrigerant in a pressure increase part (diffuser portion), thereby being capable of increasing the pressure
Implementation Method 3
draws a gas-phase refrigerant which has flowed out of an evaporator due to a suction action of an ejected refrigerant ejected from the nozzle portion
Data Source
AI summary
An ejector includes (i) a body part including a depressurizing space in which a refrigerant flowing out of a swirling space is depressurized, a suction passage that draws a refrigerant from an external, and a pressurizing space in which a jet refrigerant jetted from the depressurizing space and a suction refrigerant drawn from the suction passage are mixed with each other to be pressurized, (ii) a conical passage formation member which is arranged inside the body part, and (iii) a swirling promotion part. A nozzle passage is provided in the depressurizing space on an outer peripheral surface of the passage formation member, and a diffuser passage is provided in the pressurizing space on the outer peripheral surface of the passage formation member. The swirling promotion part includes a flow regulation plate that promotes a swirling flow of the refrigerant flowing in the diffuser passage.