Ejector and method for operating a such ejector
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Solution Overview
Problem
Ejector refrigeration systems face limitations in efficiently managing transcritical refrigeration operations, particularly in maintaining optimal performance across varying system capacities and conditions, due to the challenges of controlling primary and secondary flows within the ejector's motive and diffuser sections.
Innovation Solution
The ejector system incorporates controllable motive nozzles and adjustable diffusers, with a rotary gate mechanism and variable vane diffusers, to manage flow rates and velocities, ensuring efficient mixing and pressure recovery across different operational conditions, and a controller to optimize nozzle and diffuser configurations based on system demands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional ejector configuration with fixed nozzles and diffusers is used, then the structure is simple, but the system cannot adapt to varying operational conditions and maintains optimal performance
Solution Approach 1:
The patent implements controllable motive nozzles with adjustable opening areas and adjustable diffusers with variable passage cross-sections. These dynamic components allow the ejector to adapt its internal geometry to match varying system capacities and operational conditions, resolving the contradiction between adaptability and structural simplicity.
Solution Approach 2:
The invention changes key geometric parameters of the ejector (nozzle opening area, diffuser passage cross-section) to optimize performance across different operating conditions. By making these parameters adjustable rather than fixed, the system achieves versatility without requiring multiple separate ejector designs.
2Productivity
If the motive nozzle opening area is increased to handle full-load conditions, then the flow rate increases, but the ejector performance degrades under part-load conditions
Solution Approach 1:
The controllable motive nozzle with adjustable opening area allows the system to optimize the motive flow rate according to actual load conditions. Under full-load conditions, the nozzle opening is increased to maximize refrigeration capacity, while under part-load conditions, the opening is reduced to maintain optimal ejector performance, thus resolving the contradiction between productivity and reliability.
Solution Approach 2:
The system uses a controller to monitor operational conditions and adjust the motive nozzle opening area accordingly. This feedback mechanism ensures that the ejector operates at optimal efficiency across varying load conditions, preventing performance degradation that would occur with a fixed nozzle configuration.
3Loss of energy
If fixed diffuser geometry is used, then manufacturing is simpler, but pressure recovery is suboptimal under varying flow conditions
Solution Approach 1:
The adjustable diffuser with variable passage cross-section optimizes pressure recovery by adapting its geometry to match the flow conditions. Under varying flow rates, the diffuser adjusts its passage area to maintain optimal flow attachment and minimize energy losses, resolving the contradiction between energy efficiency and structural simplicity.
4Productivity
If a single ejector configuration is used for all operating conditions, then device complexity is reduced, but system efficiency varies significantly between full-load and part-load operation
Solution Approach 1:
The ejector design integrates multiple functions into a single device: the controllable motive nozzle serves both as a flow control element and a performance optimization element, while the adjustable diffuser provides both flow distribution and pressure recovery functions. This multi-functionality allows the system to maintain high efficiency across varying load conditions without requiring multiple separate ejector units.
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 enables the ejector system to maintain high efficiency and adaptability, ensuring optimal performance under full-load and part-load conditions by controlling flow rates and velocities, thereby enhancing system stability and energy recovery.
Implementation Method 1
The motive nozzle accelerates the primary flow and decreases the pressure of the primary flow. The pressure reduction caused to the primary flow by the motive nozzle helps draw the secondary flow into the outer member.
Implementation Method 2
The resulting combined flow may be a liquid/vapor mixture and decelerate and recover pressure in the diffuser while remaining a mixture.
Data Source
Figure 1
Figure 2~4
Figure 5~6
AI summary
An ejector (38) has ports (40, 42, 44) for receiving a motive flow and a suction flow and discharging a combined flow. The ejector has a motive flow inlet, a suction flow inlet (42), and an outlet (44). A suction flow flowpath extends from the suction flow inlet. A motive flow flowpath extends from the motive flow inlet to join the suction flow flowpath and form a combined flowpath exiting the outlet. The ejector comprises a plurality of motive flow nozzles (100, 302, 402, 602, 702, 802) along the motive flow flowpath. The motive flow nozzles are oriented to impart a tangential velocity component to the motive flow. A plurality of diffusers (130, 304, 404, 604, 704, 804) are along the combined flowpath and are oriented to recover the tangential velocity from the combined flow.