Ejector and method of manufacture therefor
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Solution Overview
Problem
Existing ejector refrigeration systems face challenges in optimizing the design and manufacturing of ejectors to enhance their efficiency and controllability, particularly in terms of pressure recovery and refrigeration effect per unit mass flow, which affects the overall performance and size of evaporators.
Innovation Solution
The design incorporates a motive nozzle insert and a diffuser body with a control needle mechanism, where the inlet body and diffuser body are threaded together, allowing for secure assembly and adjustment of the motive nozzle, and the needle guide insert is brazed to the motive nozzle insert for precise control of flow, enabling improved pressure management and refrigeration performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the ejector uses a fixed geometry design, then the manufacturing is simpler, but the pressure recovery and refrigeration effect cannot be optimized for varying operating conditions
Solution Approach 1:
The patent applies the dynamics principle by making the ejector geometry adjustable through a movable needle valve that can change the throat area of the motive nozzle. This allows the ejector to adapt its internal geometry to different operating conditions, optimizing pressure recovery and refrigeration effect dynamically rather than being fixed.
Solution Approach 2:
The patent implements parameter changes by varying the throat area of the motive nozzle through needle valve adjustment. This changes key flow parameters such as mass flow rate, pressure ratio, and refrigeration effect, enabling the ejector to operate optimally across different system conditions while maintaining a relatively simple overall structure.
2Productivity
If the ejector operates without adjustable geometry, then the device complexity is reduced, but the refrigeration effect per unit mass flow cannot be optimized
Solution Approach 1:
The movable needle valve provides dynamic adjustment capability that optimizes the refrigeration effect per unit mass flow by controlling the motive flow through variable throat area. This dynamic geometry change allows the ejector to maintain high efficiency across varying operating conditions without requiring complex multi-component control systems.
Solution Approach 2:
The needle valve mechanism serves multiple functions: it controls the motive flow rate, adjusts the pressure ratio across the ejector, and optimizes the mixing of primary and secondary flows. This multi-functionality achieves high refrigeration effect per unit mass flow while minimizing the addition of complex control components.
3Loss of energy
If the evaporator is designed larger to compensate for lower efficiency, then the heat transfer performance is maintained, but the system size and cost increase
Solution Approach 1:
By changing the ejector operating parameters through needle valve adjustment, the system optimizes the pressure ratio and mass flow distribution to maximize refrigeration effect per unit mass flow. This reduces the total mass flow required through the evaporator, allowing for smaller evaporator size while maintaining the same heat transfer capacity and reducing overall system power consumption.
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 the pressure recovery and refrigeration effect, allowing for reduced power consumption and potentially smaller evaporator sizes while maintaining high heat transfer performance, and allows for adjustable operation to optimize system performance.
Implementation Method 1
The primary refrigerant flow 103 enters the inlet 40 and then passes into a convergent section 104 of the motive nozzle 100. It then passes through a throat section 106 and an expansion (divergent) section 108 through an outlet (exit) 110 of the motive nozzle 100. The motive nozzle 100 accelerates the flow 103 and decreases the pressure of the flow.
Implementation Method 2
The pressure reduction caused to the primary flow by the motive nozzle helps draw the secondary flow 112 into the outer member.
Implementation Method 3
The outer member includes a mixer having a convergent section 114 and an elongate throat or mixing section 116. The motive nozzle outlet 110 is positioned within the convergent section 114. As the flow 103 exits the outlet 110, it begins to mix with the flow 112 with further mixing occurring through the mixing section 116 which provides a mixing zone.
Implementation Method 4
The outer member also has a divergent section or diffuser 118 downstream of the elongate throat or mixing section 116. The resulting combined flow 120 is a liquid/vapor mixture and decelerates and recovers pressure in the diffuser 118 while remaining a mixture.
Data Source
Figure 1~2
Figure 3
Figure 4~6
AI summary
An ejector has: a motive flow inlet (40); a secondary flow inlet (42); an outlet (44); a motive nozzle (204); a diffuser (118); and a control needle (132) shiftable between a first position and a second position. The ejector comprises: an inlet body (210; 400) bearing the motive flow inlet and the secondary flow inlet; a diffuser body (212) forming the diffuser and bearing the outlet; a motive nozzle insert (204) forming the motive nozzle in a compartment (240) in the inlet body; and a needle guide insert (270) in the motive nozzle insert.