Plate Heat Exchanger Orifice Layout for Two-Phase Flow Homogenization
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Solution Overview
Problem
In plate heat exchangers for motor vehicles, the installation constraints of the expansion device lead to non-homogeneous and separated flow of the liquid and gas phases due to low coolant flow rates, resulting in uneven distribution and reduced performance, particularly when the coolant reaches the inlet with an annular flow pattern.
Innovation Solution
A calibrated orifice is placed upstream of the coolant inlet manifold to atomize the liquid/gas mixture, creating a homogeneous spray jet with the liquid phase dispersed as droplets in the gas phase, ensuring a more uniform coolant flow and compensating for pressure loss with the expansion valve operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the expansion device is installed upstream of the chiller with constrained installation space, then the system compactness is improved, but the coolant flow becomes non-homogeneous and separated into liquid and gas phases
Solution Approach 1:
The inlet manifold is divided into multiple zones with strategically positioned orifices that segment the flow path. This segmentation allows the liquid and gas phases to be separately controlled and distributed more uniformly across the channels, preventing phase separation while maintaining compact installation.
Solution Approach 2:
The orifices are designed with specific diameter ratios (d/D between 0.05 and 0.5) to change the flow parameters. By controlling the orifice size relative to the manifold diameter, the system transforms the separated two-phase flow into a more homogeneous mixture, resolving the contradiction between compact installation and flow uniformity.
2Stability of the object's composition
If calibrated orifices are placed inside the manifold to inhibit liquid phase backflow, then the liquid phase distribution is improved, but significant pressure loss occurs in the coolant flow
Solution Approach 1:
Instead of uniformly distributing orifices throughout the manifold, the invention positions them at specific locations where phase separation is most problematic. This localized approach provides liquid phase control exactly where needed while minimizing the total number of orifices and reducing overall pressure loss.
Solution Approach 2:
The orifice diameter ratio (d/D between 0.05 and 0.5) is optimized to balance two competing requirements: small enough to inhibit liquid backflow and improve distribution, but large enough to limit pressure loss. This parameter optimization resolves the contradiction between liquid distribution and pressure maintenance.
3Use of energy by moving object
If the coolant flow rate is kept low to meet system requirements, then the energy consumption is reduced, but the liquid and gas phases separate and flow non-homogeneously
Solution Approach 1:
The low flow rate is compensated by segmenting the flow path through strategically positioned orifices in the inlet manifold. This segmentation creates multiple small flow paths that maintain adequate flow velocity and mixing even at low overall flow rates, preventing phase separation without requiring increased energy consumption.
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 enhances the homogeneity of the coolant flow and liquid fraction distribution within the channels, improving the exchanger's performance by maintaining a consistent flow quality and quantity across all channels.
Implementation Method 1
there is a calibrated orifice, which receives a liquid/gas mixture and atomizes it in the inlet manifold
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Method for homogenizing a flow of coolant fluid inside a plate heat exchanger, the heat exchanger comprising two support end plates (2, 3) on which coolant inlet and outlet connectors (4, 6) and water inlet and outlet connectors (5, 7) are arranged, and a stack (10) of thermal exchange plates interposed between the support end plates (2, 3). Through the stack (10) of thermal exchange plates, a coolant inlet manifold (14) is formed which fluidically connects the coolant inlet connector (4) to the first channels, a coolant outlet manifold, a water inlet manifold and a water outlet manifold. Upstream of the coolant inlet manifold (14), between the coolant inlet connector (4) and the coolant inlet manifold (14), there is a calibrated orifice (20) configured to atomize a liquid/gas mixture entering the coolant inlet manifold (14).