With the rapid growth of global artificial intelligence computing power and the continuous increase in chip thermal design power consumption (TDP), the cooling demand of data centers is facing unprecedented challenges. At the same time, the increasingly stringent energy-saving and carbon-reduction policies around the world have further promoted the innovation of cooling technology. In this context, traditional air cooling solutions have gradually become difficult to meet the dual requirements of efficient heat dissipation and energy saving. Liquid cooling technology is rapidly rising due to its excellent heat dissipation performance and significant energy-saving advantages, becoming the mainstream choice for data center cooling solutions. As the core equipment for data processing and storage, the performance and stability of the server are directly related to the operating efficiency of the entire system. The core components of the server - including the motherboard, CPU, memory, hard disk and graphics card - will generate a lot of heat under continuous high-load operation. If the heat cannot be dissipated in a timely and effective manner, it will seriously affect the performance and life of the server. To this end, advanced liquid cooling systems have been introduced into server cooling solutions and installed directly on major heat sources such as CPUs and graphics cards to significantly improve heat dissipation efficiency.

Part 1：Water  Block Structure and Working Principle

One of the core components of the liquid cooling system is the water  block, which is usually made of copper or aluminum materials with high thermal conductivity and is designed with precise water channels and heat sink structures. These water  blocks fit tightly to the surface of heat sources such as CPUs and GPUs, and quickly absorb and transfer heat through the cooling water circulating inside. The heat is then transported to the heat sink, which is then circulated through the water cooling system and eventually dissipated into the surrounding air.

Figure 1: Chip thermal power consumption trends of mainstream chip manufacturers

1- Common water  block types and characteristics

l Microchannel water block

Features: The microchannel water block adopts a precise micro-water channel design. The water channel structure is fine and complex, which can significantly increase the contact area between the coolant and the heat-generating components, thereby greatly improving the heat dissipation efficiency. The micro-water channel design can also produce a strong turbulence effect during the flow of the coolant, further enhancing the convection heat transfer coefficient and achieving efficient heat transfer.

Application scenarios: It is particularly suitable for CPUs and GPUs with high heat generation, especially in high-performance computing, overclocking, and data centers, which have extremely high heat dissipation requirements.

l Large flow water  block

Features: The internal structure of the large-flow water  block is relatively simple, usually using a copper plate or etched groove design, and the manufacturing cost is low. Its core advantage is that it relies on high-speed water flow to quickly remove heat, and is suitable for use with a large-flow water cooling system. Although the structure is simple, its efficient heat dissipation capacity makes it a very cost-effective choice.

Application scenario: Suitable for scenarios with certain requirements for heat dissipation efficiency but limited budget, such as mid-to-high-end DIY computer systems or small and medium-sized server clusters.

l Injection type water  block

Features: The jet-type water-cooling block sprays the coolant from a narrow nozzle to the micro-channel bottom plate at high speed through the guide plate, forming a strong turbulence effect and significantly improving the heat dissipation efficiency. This design not only increases the contact area between the coolant and the base, but also further optimizes the heat exchange performance through high-speed flow.

Application scenarios: Suitable for high-performance CPUs and GPUs, especially in high-heat dissipation requirements and high-flow scenarios, such as overclocking computing, artificial intelligence training, and graphics rendering.

2-General structure of water  block

A water  block is a metal block with water channels inside, usually made of copper or aluminum. It does not come into contact with the CPU, graphics card or other heat generating devices. Its structural design directly determines the quality of heat dissipation performance. A typical water block usually consists of the following key parts:

l The base is usually made of high thermal conductivity materials such as copper or aluminum alloy, and the surface is finely processed to ensure close contact with the heat-generating components. The base is equipped with a complex flow channel design to increase the contact area between the coolant and the base.

l The cover plate, together with the base, forms a flow channel sealing cavity to protect the flow channel, seal and other components inside the water block from dust, impurities and external physical damage.

l The water inlet and outlet are the interfaces for the coolant to enter and exit the water cooling head. They are generally designed on the side or top of the water cooling head to ensure that the coolant can flow in and out smoothly. The position design needs to consider the flow path of the fluid to reduce flow resistance and increase the flow rate of the coolant.

l Clips are used to firmly fix the water cooling head to the CPU or other heat-generating components to ensure a tight foundation and achieve efficient heat conduction.

Figure 2: Typical structure of water  block

3- Comprehensive optimization of heat dissipation performance

l Flow channel design optimization

Increase the contact area of the flow channel: By designing narrower and denser flow channels, the contact area between the coolant and the base can be significantly increased, thereby improving the convective heat transfer coefficient. For example, the microchannel design has a fine water channel structure. The design parameters of the microchannel water  block (such as channel width, height, and spacing) have a decisive influence on its heat dissipation efficiency: as the channel width decreases, the heat transfer coefficient increases significantly, thanks to the enhanced turbulence effect of the coolant flow in the narrow channel, thereby improving the heat exchange efficiency; the higher channel height helps to increase the flow space of the coolant, thereby improving the heat transfer performance; the smaller channel spacing can increase the contact area between the coolant and the heat source, thereby improving the heat dissipation efficiency.

It can also be optimized by optimizing the flow channel layout and reducing the flow channel bends: a reasonable flow channel layout can ensure that the coolant evenly covers the surface of the heat-generating components and reduce the local temperature difference. The bends in the flow channel will increase the head loss and internal flow resistance, thereby reducing the cooling efficiency. The number of bends should be minimized in the design. If it cannot be avoided, the bends should be designed as smooth transitions to reduce the pressure drop and optimize the flow performance.

l High thermal conductivity materials: The base of the water  block is usually made of high thermal conductivity materials such as pure copper or aluminum alloy. These materials can efficiently transfer heat from the heat source to the coolant, thereby improving the overall heat dissipation performance.

l Structural parameter optimization, such as base substrate thickness, fins, spoiler structure, etc. The increase in substrate thickness will lead to an increase in the maximum temperature, so the design needs to find the best balance between heat dissipation effect and structural strength; by increasing the height, thickness and spacing of the fins, the heat dissipation performance can be improved, but at the same time, the flow resistance will also increase. Find the best fin design combination to maximize the heat dissipation performance. The shape of the spoiler column can effectively enhance the turbulence effect and improve the heat exchange efficiency.

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