Plate-Fin Heat Exchanger Flow Segmentation for Lower Pressure Drop
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Plate-fin heat exchangers in air separation plants face limitations in efficiency and scalability due to the need for high fin density, which increases pressure drop and complicates the design and fabrication, especially when trying to connect heat exchangers in series.
Innovation Solution
A plate-fin heat exchanger design with alternating layers for cooling and warming streams, where each layer is subdivided into transverse sections with parallel flow passages, allowing for indirect heat exchange and minimizing pressure drop by distributing flow within sections rather than across the entire length, enabling easier scaling and reduced pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If fin density is increased to provide effective heat exchange area in compact heat exchangers, then heat transfer surface area per unit volume increases, but pressure drop increases
Solution Approach 1:
The heat exchanger is divided into multiple independent cores that can be connected in parallel or series. Each core contains a stack of plates with flow passages, and the segmentation allows flow distribution without requiring excessive fin density within a single compact unit, thereby reducing pressure drop while maintaining heat exchange effectiveness
Solution Approach 2:
Inlets and outlets are positioned at opposite ends of the longest dimension (length) rather than at the same end, creating a counter-current flow arrangement. This dimensional optimization improves heat exchange efficiency without requiring increased fin density, thus avoiding the pressure drop penalty associated with higher compactness
2Productivity
If heat exchangers are connected in series to handle higher flows, then heat exchange duty increases, but flow redistribution complexity and pressure drop increase
Solution Approach 1:
The system uses multiple independent cores that can be connected in series to handle higher flows. Each core is a self-contained unit with its own inlet and outlet connections, eliminating the need for complex internal flow redistribution mechanisms when scaling up capacity. This modular segmentation simplifies the overall system complexity while maintaining high productivity
Solution Approach 2:
Each core is designed as a universal module that can function independently or be combined with other cores. The standardized inlet/outlet positioning and flow passage configuration allow cores to be interconnected in various series or parallel arrangements without requiring custom flow redistribution designs, reducing overall device complexity
3Reliability
If inlets and outlets are positioned at opposite ends of the longest dimension, then counter-current heat exchange is achieved, but heat exchanger length increases beyond brazing oven capacity
Solution Approach 1:
The long heat exchanger required for counter-current flow is segmented into multiple shorter cores, each fitting within brazing oven dimensions. The cores are connected in series to achieve the total length needed for effective counter-current heat exchange, while each individual core remains compact enough for standard fabrication equipment
Solution Approach 2:
The heat exchanger uses a stacked plate configuration where the length dimension is optimized for counter-current flow, while the width and height dimensions are constrained by brazing oven capacity. Multiple such stacks are connected in series along the length direction, allowing the system to achieve the required heat exchange efficiency without any single component exceeding fabrication limits
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 design enhances heat exchange efficiency by allowing higher fin density without excessive pressure drop, simplifies the layering and scaling of heat exchangers, and reduces the complexity of flow redistribution, making it easier to connect heat exchangers in series while maintaining effective heat transfer.
Implementation Method 1
the warm and cold fluids to be brought into an indirect heat exchange relationship are located in alternating layers
Implementation Method 2
indirect heat exchange between at least a first fluid flowing through the first layer and at least second and third fluids flowing through the second layer
Data Source
AI summary
A plate-fin heat exchanger having alternating layers for exchanging heat between fluids to be warmed against fluids to be cooled. One or both of the layers is subdivided into flow passages to allow for the flow of two or more fluids flowing through one of the layers to engage in indirect heat transfer with one or more fluids flowing through another adjacent layer. The flow through the heat exchanger is parallel to the width of the heat exchanger. The first and second layers provide a greater cross-sectional flow area for each of the fluids than otherwise would have been provided had the fluids flow been parallel to the length of the heat exchanger with layers thereof dedicated to the flow of each of the fluids.