Insert for evaporator header
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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 result in reduced contact between the working fluid and the evaporator, leading to inefficiencies and potential damage, as the fluid fails to effectively transfer heat along the entire length of the sidewall in parallel flow passage designs.
Innovation Solution
A header insert for the evaporator header outlet port featuring a convergent-divergent nozzle shape with a conical tip member and runners, which directs fluid flow to ensure contact with the sidewall of the evaporator passages, enhancing heat transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a parallel flow passage design is used in the evaporator, then heat transfer area is increased, but under adverse gravity conditions fluid contact with the evaporator sidewall is reduced
Solution Approach 1:
The header outlet is segmented into multiple outlet ports, each equipped with a flow director element. This segmentation allows independent control of fluid flow into each evaporator passage, ensuring that each passage receives properly directed flow that maintains contact with the sidewall, thus resolving the contradiction between having multiple parallel passages for heat transfer and ensuring reliable fluid contact under adverse gravity conditions.
Solution Approach 2:
A flow director element is introduced as an intermediary component between the header outlet and the evaporator passages. This flow director actively shapes and directs the fluid flow, ensuring that the fluid properly contacts the evaporator sidewall. The flow director acts as a mediator that solves the flow distribution problem without requiring changes to the evaporator passage structure itself.
2Device complexity
If flow distribution is not optimized, then device complexity is reduced, but evaporator performance is reduced
Solution Approach 1:
The flow director element is designed with specific geometric features (conical shape, angled surfaces) that are optimized for the local flow conditions at the header outlet. This local optimization of the flow director geometry ensures effective flow direction and sidewall contact without requiring complex control systems or sophisticated flow distribution structures throughout the entire evaporator assembly.
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 improves heat transfer efficiency by ensuring uniform fluid distribution and increased contact between the working fluid and the evaporator sidewall, even in microgravity environments, thereby enhancing the overall performance and longevity of the refrigeration system.
Implementation Method 1
A header insert for the evaporator header outlet port featuring a convergent-divergent nozzle shape with a conical tip member and runners, which directs fluid flow to ensure contact with the sidewall of the evaporator passages
Implementation Method 2
The solution improves heat transfer efficiency by ensuring uniform fluid distribution and increased contact between the working fluid and the evaporator sidewall
Data Source
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AI summary
Disclosed is an evaporator header insert, including: a header insert body (210) that extends along a body center axis between body inlet (230) and outlet (240) ends, a center passage (250) located within the header insert body (210), the center passage (250) extending from the body inlet end (230) to the body outlet end (240) 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.