How to Design and Optimize Water-Cooled Plate Channels for Maximum Efficiency

 

The entire liquid cooling system includes components such as the liquid cooling plate, liquid cooling medium, pump, pipes, and radiator.

 

Generally, the thermophysical properties of commonly used liquid cooling fluids are shown in the table below:

 

▲ Liquid Cooling Properties

 

From the table above, it is clear that the selection of the liquid cooling medium has a fixed impact on the cooling efficiency of the entire system. Without changing other conditions, priority should be given to low-cost media that meet environmental requirements (such as altitude and ambient temperature).

 

However, the water-cooled plate is also a crucial part of the liquid cooling system. As the heat exchange component of the liquid cooling system, it contains heat exchange channels, i.e., flow paths. The design of these internal flow paths can significantly affect the heat exchange efficiency of the entire system, with considerable variability.

 

Therefore, today we will not discuss liquid cooling media, but instead, using pure water as an example, we will analyze the design and optimization approach of water-cooled plate flow paths.

 

In the design of the water-cooled plate structure, the following factors need to be considered:

 

• Heat Exchange Performance Requirements: Under the set flow rate and temperature difference between inlet and outlet water, achieve the desired temperature rise of the heat source and the heat dissipation target of the radiator, fulfilling the performance requirements.
• Strength and Pressure Requirements: In some projects, due to environmental use or installation requirements within the system, specific instructions are given for surface pressure and overall stress conditions of the water-cooled plate.
• Corrosion Resistance: The liquid cooling medium flows through the channel for extended periods, and high temperatures can accelerate the degradation of metal materials, potentially leading to blockages that impact cooling efficiency.
• Leak Prevention: The design of the cover plate, upper and lower surfaces, sealing strips, and even welding methods should prevent leakage.
• Cost-Effectiveness: Reducing costs from factors such as production feasibility, material selection, process complexity, flow resistance, and heat resistance, while minimizing pump pressure and labor time.

 

To meet the above requirements, comprehensive design considerations must be made regarding materials, structure, and manufacturing methods.

 

 

I Water-Cooled Plate Material Selection

 

The material of the water-cooled plate affects the heat exchange performance between the channel and the cooling water. High thermal conductivity materials should be used for water-cooled plates to effectively reduce the system's overall thermal resistance. Common materials like aluminum and copper exhibit the following properties:

 

▲ Material Properties

 

Aluminum alloys, as the most commonly used cooling material, have advantages such as high thermal conductivity, low density, good machinability, excellent corrosion resistance, and favorable physical and mechanical properties.

 

The corrosion protection process for aluminum profiles is well-established, ensuring the long-term reliable use of water-cooled plates.

 

Aluminum heat sinks used in electronic products are typically made from 50 or 60 series alloys, such as AL5051, 60601, and 6063. These materials offer excellent thermal conductivity, corrosion resistance, machinability, and are suitable for anodizing and CNC processing of complex flow channels.

 

This study focuses on the design and optimization approach of water-cooled plate flow paths, assuming predetermined flow rates and basic pressure drop requirements.

 

 

II Basic Types of Water-Cooled Plate Flow Paths

 

The main types of water-cooled plate flow paths include: planar, W-shaped, circular, cylindrical, and Archimedean spiral channels. The following are brief descriptions of each, with corresponding images:

 

▲ Planar Water-Cooled Plate Image

 

▲ W-Shaped Water-Cooled Plate Image

 

▲ Circular Water-Cooled Plate Image

 

▲ Cylindrical Water-Cooled Plate Image

 

In the cylindrical water-cooled plate example, the internal design can include rectangular columns or elongated heat sinks to enhance the contact area with the water flow.

 

▲ Archimedean Spiral Flow Path Image

 

Referring to this physical object, I purposely used solidworks to design its 3D structure as shown below.

 

▲ single-cycle Flow Path Image

 

▲ double loop Flow Path Image

 

The above are typical water-cooled flow path designs. Next, we will explore the optimization approach for these designs.

 

 

III Flow Path Optimization Approach

 

The optimization approach for water-cooled plate flow paths shares similarities with airflow path optimization in air-cooled systems.

 

For air-cooled solutions, the principles of airflow path optimization can be referenced in the article: "Principles for Optimizing Airflow Paths in Thermal Design for Electronic Products."

• Increase Circuits: After initial planning of the water flow path design, numerical simulations may reveal that cooling efficiency does not meet expectations, with higher thermal resistance. In this case, increasing the number of circuits (e.g., from single to dual or more circuits) can enhance heat exchange.
• Increase Heat Dissipation Area: If internal structure space allows, adding cylindrical or rectangular fins in staggered or aligned configurations can improve optimization within the flow path.
• Optimize Internal Water Flow Speed: When the inlet cross-sectional area is fixed, increasing the flow path cross-sectional area reduces flow speed, hindering rapid heat exchange. However, simply reducing the cross-sectional area to increase speed can lead to higher flow resistance.
• Balance Water-Cooled Area: Ensure the flow path covers the contact surface of the heat source evenly. In situations with limited area or space, the Archimedean spiral flow path is a good option.
• Avoid Short-Circuits: When the inlet and outlet are too close, design rib structures in the flow path to extend it and distribute water below the heat source, preventing the water from directly flowing from inlet to outlet.
• Avoid Excessive Flow Length: In cases with vertically layered heat sources, the usual approach may be to design flow paths from top to bottom, or vice versa, which can cause a significant temperature difference between the front and back. Consider separate cooling for each layer to resolve this issue.
• Minimize Bends: Bends increase head loss and flow resistance. If bends are unavoidable, ensure smooth transitions to reduce pressure drop while increasing heat dissipation area.

 

During the optimization process, ensure that system flow resistance, thermal resistance, and structural strength (e.g., surface pressure) meet project requirements while considering production feasibility and cost.

 

 

IV Optimization Design Methods

 

• Hypothesis Analysis: Based on the original project, apply optimization ideas such as increasing heat dissipation area, reducing cross-sectional area, or adding circuits, and calculate theoretical results.
• Numerical Simulation: Based on the analysis, create multiple flow path design models, simulate under required conditions, and compare results.
• Experimental Testing: Build experimental models and tests to verify the hypothesis analysis and numerical simulation results.