Flooded Evaporator Flow Diffuser for Part-Load Pressure Control
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Solution Overview
Problem
Flooded evaporators face challenges in maintaining even refrigerant flow distribution during part load operations or when operating conditions deviate from nominal conditions, leading to flow separation and inefficiencies due to varying refrigerant pressures and densities.
Innovation Solution
A refrigerant flow diffuser with a movable element and stationary element, where the moving element adjusts under pressure forces to maintain constant pressure difference between the diffuser and shell, ensuring optimal flow distribution by adapting the geometry of openings in response to changing pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the diffuser geometry is optimized for full load operation, then refrigerant flow distribution is improved at maximal flow, but flow distribution deteriorates during part load operation
Solution Approach 1:
The diffuser incorporates a movable element that can dynamically adjust its position in response to varying refrigerant pressure conditions. This dynamic adjustment allows the diffuser geometry to adapt between full load and part load operations, maintaining optimal flow distribution across different operating conditions rather than being fixed for a single design point
Solution Approach 2:
The invention changes the physical state or configuration of the diffuser by introducing a movable element whose position varies with operating conditions. This parameter change (position of moving element) allows the system to optimize performance across different load conditions by adjusting the effective opening geometry in response to pressure differential changes
2Productivity
If smaller openings are provided in the entering section to preserve constant flow at high pressure, then flow distribution is improved at full load, but flow separation occurs at part load due to high variations in individual opening flows
Solution Approach 1:
The movable element dynamically adjusts the effective opening size in response to pressure conditions. At part load, when pressure differentials decrease, the moving element shifts to maintain appropriate flow distribution, preventing the high flow variations and flow separation that occur with fixed smaller openings
Solution Approach 2:
The diffuser uses the refrigerant pressure itself as the actuating force to move the element and adjust the openings. The system self-regulates based on the pressure differential without requiring external control mechanisms, automatically maintaining flow distribution uniformity across varying load 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
This solution ensures consistent refrigerant flow distribution across the evaporator, maintaining efficiency even under varying operating conditions by dynamically adjusting the diffuser geometry to match changing pressure differentials, thereby preventing flow separation and ensuring stable performance during part load operations.
Implementation Method 1
the moving element being movable with respect to the stationary element under action of a pressure force exerted by the refrigerant flow
Implementation Method 2
the pressure force FP exerts upwards against a gravity force exerted on the moving element
Implementation Method 3
the pressure force FP exerts upwards against a gravity force exerted on the moving element
Data Source
Figure 1
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Figure 3
AI summary
This heat exchanger (2), such as a flooded evaporator, comprises a shell (4) extending along a longitudinal axis (X), an inlet pipe (6) and an outlet pipe (8), through which respectively enters (F1) and exits (F2) a refrigerant flow, and a bundle of pipes (10) crossing the shell (4) along the longitudinal axis (X), and comprising a refrigerant flow diffuser (12) provided inside the shell (4) downstream the inlet pipe (6), the refrigerant flow diffuser (12) extending along the longitudinal axis (X) and comprising openings (14a, 14b) through which the refrigerant flows. The refrigerant flow diffuser (12) comprises a moving element (16) and a stationary element (18), the moving element (16) being movable with respect to the stationary element (18) under action of a pressure force (FP) exerted by the refrigerant flow so that the refrigerant flow going through the openings (14a, 14b) is adjusted and a differential refrigerant pressure between refrigerant pressure downstream (P2) and upstream (P1) the refrigerant flow diffuser (12) is kept constant.