Evaporator Header Insert Nozzle for Adverse-Gravity Flow Distribution
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Solution Overview
Problem
Under adverse gravity conditions, such as in aerospace applications, the flow dynamics into evaporator passages from the header in refrigeration systems result in reduced contact between the working fluid and the evaporator, leading to reduced effectiveness of the system.
Innovation Solution
A header insert for the evaporator header outlet port with a convergent-divergent shaped nozzle and a conical tip member is used to direct fluid flow, ensuring it contacts the sidewall of the evaporator passages, improving heat transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional header flow distribution is used, then system simplicity is maintained, but under adverse gravity conditions fluid contact with evaporator sidewalls is reduced leading to decreased heat transfer efficiency
Solution Approach 1:
The header insert divides the single large flow outlet into multiple smaller flow paths using runner structures. This segmentation allows the fluid to be distributed across multiple evaporator passages simultaneously, ensuring each passage receives adequate fluid flow and maintains contact with evaporator sidewalls even under adverse gravity conditions.
Solution Approach 2:
The header insert creates different flow characteristics at different locations by using convergent-divergent nozzle portions and runner structures. The local flow dynamics are optimized so that fluid is directed toward evaporator sidewalls at each outlet location, ensuring consistent heat transfer performance across all passages while maintaining overall system simplicity.
2Area of stationary object
If fluid flow is reduced to smaller area in individual evaporator paths, then parallel flow passages can be used for large footprint area heat removal, but flow distribution uniformity becomes critical to system performance
Solution Approach 1:
The header insert uses convergent-divergent nozzle portions that change the fluid flow parameters (velocity, pressure) as fluid moves through different sections. This parameter transformation helps equalize flow distribution across multiple passages by creating backpressure and directing flow uniformly to all runners and evaporator passages.
Solution Approach 2:
The header insert acts as an intermediary device between the main header and individual evaporator passages. It mediates the flow distribution by using runner structures and nozzle portions to evenly divide the refrigerant flow among multiple passages, ensuring uniform flow rates without requiring high manufacturing precision in the evaporator passages themselves.
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
The solution enhances fluid flow distribution and heat transfer efficiency by ensuring the fluid contacts the sidewall of the evaporator passages, thereby improving the overall performance of the refrigeration system under adverse gravity conditions.
Implementation Method 1
the body nozzle portion having a convergent-divergent shape so that the body nozzle portion has a convergent segment, a divergent segment and a neck segment therebetween
Implementation Method 2
a conical tip member, fixed to the body outlet end and disposed at least partially within the divergent segment of the body nozzle portion so that a conical outlet passage is formed therebetween
Implementation Method 3
an evaporator for evaporating a single-phase liquid or two-phase fluid in a refrigerant system
Implementation Method 4
an evaporator for evaporating a single-phase liquid or two-phase fluid in a refrigerant system
Data Source
AI summary
Disclosed is an evaporator header insert, including: a header insert body that extends along a body center axis between body inlet and outlet ends, a center passage located within the header insert body, the center passage extending from the body inlet end to the body outlet end along the body center axis, the center passage surface defining: a center passage inlet portion at the body inlet end; a center passage outlet portion, at the body outlet end, that defines a body nozzle portion on the body center axis, wherein the body nozzle portion has a convergent-divergent shape so that the body nozzle portion has a convergent segment, a divergent segment and a neck segment therebetween; and a conical tip member, fixed to the body outlet end and disposed at least partially within the divergent segment of the body nozzle portion so that a conical outlet passage is formed therebetween.