Channel Guide Distributor Geometry for Uniform Two-Phase Flow
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Solution Overview
Problem
In heat exchangers, such as mini-channel, micro-channel, plate-fin, and brazed-plate heat exchangers, the distribution of two-phase fluid flow is challenging due to stratification in the distributor, leading to uneven mass fraction distribution among fin passages, resulting in poor system performance.
Innovation Solution
A channel guide distributor is designed with a flanged body, nozzle, diffuser, pin, cone, and post, featuring aligned and equidistantly spaced apertures along its longitudinal axis, which helps maintain a homogeneous liquid/gas mixture and ensures uniform distribution to each layer of the heat exchanger.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a piccolo distributor with a closed-end tube is used to distribute two-phase fluid flow, then the flow can be distributed among multiple layers and ports, but the two-phase fluid stratifies due to deceleration causing liquid to pool at the end and vapor to leave through early ports
Solution Approach 1:
The distributor cavity is designed with specific geometry and surface characteristics before the two-phase fluid enters, creating conditions that promote annular flow pattern and prevent stratification from occurring in the first place. The cavity geometry is predetermined to maintain flow homogeneity throughout the distributor length.
Solution Approach 2:
The distributor cavity geometry parameters (length, diameter, surface roughness) are specifically optimized to control flow characteristics. By adjusting these geometric parameters, the flow regime is maintained as annular throughout the distributor, preventing stratification and ensuring uniform distribution of both liquid and vapor phases to all ports.
2Productivity
If the flow stratifies in the distributor, then liquid pools at the end of the tube while vapor leaves through early ports, but the mass fraction provided to each fin passage is not properly apportioned resulting in poor system performance
Solution Approach 1:
The distributor cavity geometry is designed in advance to create flow conditions that ensure proper mass fraction distribution to all fin passages before the fluid reaches the distribution ports. The cavity dimensions and surface characteristics are predetermined to maintain homogeneous two-phase flow throughout the distributor length.
Solution Approach 2:
Specific geometric parameters of the distributor cavity (length-to-diameter ratio, surface roughness, entry angle) are optimized to control the flow regime and ensure uniform mass fraction distribution. These parameter adjustments prevent stratification and ensure each fin passage receives the correct proportion of liquid and vapor phases for optimal heat exchanger performance.
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 provides improved heat exchanger performance by ensuring uniform distribution of the fluid mixture, increasing the coefficient of performance, reducing power consumption, and allowing for a smaller and lighter evaporator.
Implementation Method 1
a diffuser fluidly connected to the nozzle
Implementation Method 2
a nozzle fluidly connected to the flanged body
Implementation Method 3
Distribution of two-phase fluid flow (liquid and gas) inside heat exchangers
Data Source
AI summary
A channel guide distributor of a heat exchanger including a flanged body, a nozzle fluidly connected to the flanged body, a diffuser fluidly connected to the nozzle, a pin operably connected to the nozzle, a cone operably connected to the nozzle and a post removably connected to the flanged body and configured to receive the diffuser. The post having a tubular portion, an open end, a closed end, an inner surface, an outer surface, a post longitudinal axis, and twenty-four apertures in the tubular portion. The apertures are aligned linearly along the post longitudinal axis and equidistantly spaced. A diameter of the outer surface of the tubular portion is about 1.156±0.003 inches (2.936±0.01 centimeters).