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 in refrigeration systems result in reduced contact between the working fluid and the evaporator, leading to reduced effectiveness of the system due to non-uniform fluid distribution and heat transfer inefficiencies.
Innovation Solution
A header insert with a convergent-divergent nozzle shape and a conical tip member is introduced at the evaporator header outlet port, which directs fluid flow to ensure better contact with the evaporator passage sidewalls, enhancing heat transfer and pressure uniformity by guiding the fluid through a center passage and conical outlet passage, and optionally includes internal inserts with helical fluid passages and ribs for improved distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional header flow distribution is used, then system simplicity is maintained, but fluid distribution uniformity deteriorates under adverse gravity conditions
Solution Approach 1:
The header flow distribution problem is segmented by introducing separate functional components: a flow distribution member with multiple outlet ports and individual flow control members for each passage. This segmentation allows independent optimization of each flow path while maintaining overall system functionality, resolving the contradiction between distribution uniformity and structural simplicity.
Solution Approach 2:
The flow distribution member performs preliminary flow distribution before fluid enters the evaporator passages. By pre-distributing the fluid through multiple controlled outlets, the system ensures uniform flow distribution from the start, preventing gravity-induced flow imbalances without requiring complex active control mechanisms.
2Stress or pressure
If header reduces flow area, then pressure drop is reduced, but flow distribution uniformity to individual passages deteriorates
Solution Approach 1:
The flow distribution member provides different local flow characteristics to different passages through individually adjustable flow control members. Each passage receives optimized flow control tailored to its specific requirements, ensuring uniform distribution while maintaining appropriate pressure drop across the system.
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 fluid distribution and heat transfer efficiency by ensuring the fluid contacts the evaporator passage sidewalls effectively, enhancing 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
enhancing heat transfer and pressure uniformity by guiding the fluid through a center passage and conical outlet passage
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.