Amid the explosive growth of AI computing power, the power density of individual server racks in data centers has surged from the traditional 5-10kW to over 50kW, with some AI cluster racks even exceeding 100kW. Such high power density has made thermal management a core bottleneck restricting the stable operation of data centers. Liquid cooling systems, with their higher heat dissipation efficiency, are gradually replacing air cooling as the mainstream solution. Within liquid cooling circulation systems, the water distributor (also known as a Manifold), acting as the “flow commander” made for precise coolant distribution, undertakes the critical task of accurately distributing cooling fluid to each server. Its performance directly determines the efficiency and stability of the entire thermal management system.
I. Understanding Water Distributors (Manifolds): The “Flow Distribution Core” Made for AI Data Centers
For the liquid cooling system of an AI data center, a water distributor (Manifold) is not a complex precision instrument, but a core component made for realizing “centralized water supply and distributed distribution”. Simply put, it is a flow distribution device made for AI server cooling needs, manufactured using stainless steel pipes as the base material and processes like laser welding. Its core function is to evenly split the cooling fluid from the main pipe into N branch ports, which are then connected to individual AI servers to provide continuous and stable cooling fluid supply for device heat dissipation.
In terms of structure, a water distributor (Manifold) mainly consists of three parts:
•Main Pipe: Serving as the “main artery” for cooling fluid, it is usually made of corrosion-resistant, high-strength stainless steel. It is responsible for receiving a large volume of cooling fluid (such as industrial chilled water, ethylene glycol solution, etc.) from the cold source.
•Branch Ports: N branch ports welded onto the main pipe, with the number matching the number of servers. These ports act as “sub-vessels” made for directing cooling fluid to individual devices.
•Control Components: Some high-end water distributors (Manifolds) are equipped with flow control valves or flow meters made for real-time monitoring and fine-tuning the cooling fluid flow of each branch, ensuring distribution accuracy.
Its working principle can be intuitively understood through a specific scenario: If the cooling fluid flow in the main pipe is 100 liters per minute, and the water distributor (Manifold) is designed with 10 branch ports, each port can distribute 10 liters per minute of cooling fluid to the corresponding AI server under ideal conditions. If the main pipe flow is increased to 1000 liters per minute and the number of branch ports is expanded to 100, each port can still stably distribute 10 liters per minute of flow. This characteristic of “equal distribution of total volume and on-demand supply” is perfectly suited to the heat dissipation needs of multi-server clusters in AI data centers, confirming it as a component made for such scenarios.
II. Production Process of Water Distributors (Manifolds): “Precision Control” Made for Reliable Operation
The production of water distributors (Manifolds) is not a simple process of pipe cutting and welding. Instead, it requires full-process precision control made for three core requirements: sealability, pressure resistance, and flow uniformity. Its typical production process can be divided into 5 key steps:
1. Material Selection: Laying the Foundation Made for Durability
The core material is preferably 304 or 316 stainless steel. 304 stainless steel has good corrosion resistance and cost-effectiveness, making it suitable for general liquid cooling scenarios. 316 stainless steel, with the addition of molybdenum, has stronger corrosion resistance and can be used with coolants containing a high proportion of ethylene glycol or slightly corrosive coolants, making it ideal for high-demand AI clusters. During material selection, the purity and mechanical strength of the steel must be strictly tested to avoid potential leaks caused by material defects—this strict selection is made for ensuring long-term durability.
2. Main Pipe Processing: Ensuring Smooth Flow Made for Efficient Distribution
Based on the flow requirements of the data center, stainless steel raw materials are cut into main pipes of specified lengths. The two ends of the pipes are then precision-machined using a lathe to ensure the inner walls are smooth (reducing fluid resistance) and the ports are flat (facilitating connection with cold source pipes). Meanwhile, according to the number and spacing of branch ports, marking positions for holes are made on the main pipe, with a marking error controlled within ±0.5mm to avoid affecting subsequent flow distribution accuracy. This precise processing is made for laying the groundwork for efficient coolant distribution.
3. Branch Port Prefabrication and Laser Welding: Ensuring Sealing and Strength Made for High-Pressure Scenarios
Branch ports are typically made by cutting stainless steel pipes of the same material, and their inner walls need to be polished in advance. The welding process is the core of production: laser welding technology is used, where a high-energy-density laser beam fuses the branch ports with the marked positions on the main pipe. The welding temperature can reach over 1500℃, ensuring seamless connection between the ports and the main pipe. Compared with traditional arc welding, laser welding produces narrower welds and a smaller heat-affected zone, effectively preventing pipe deformation while achieving stronger sealing, which can withstand a working pressure of over 1.6MPa (meeting the pressure requirements of data center liquid cooling systems). This advanced welding method is made for adapting to the high-pressure operating environment of liquid cooling systems.
4. Precision Testing: Eliminating Potential Risks Made for Stable Operation
After welding, two key tests are required:
•Sealability Test: The entire water distributor (Manifold) is pressurized to 2.0MPa (25% higher than the working pressure) and immersed in water for 30 minutes. If no bubbles are generated, the sealability is considered qualified.
•Flow Uniformity Test: A specified volume of fluid is pumped into the main pipe, and the outflow of each branch port is measured. The flow deviation of each port is required to be no more than ±5%. If the deviation is excessive, adjustments are made by fine-tuning the port angle or inner wall smoothness. These strict tests are made for eliminating potential risks and ensuring stable operation in actual use.
5. Surface Treatment and Assembly: Enhancing Durability Made for Long-Term Use
Finally, the surface of the water distributor (Manifold) undergoes passivation treatment (forming an oxide protective film to enhance corrosion resistance). Flow control valves, flow meters, and other control components are assembled as required, and the finished product is packaged. This surface treatment and assembly process is made for extending the service life of the product and adapting to long-term use in data centers.
III. The Importance of Water Distributors (Manifolds): An “Irreplaceable Link” Made for AI Data Center Thermal Management
In the liquid cooling system of an AI data center, although the water distributor (Manifold) seems “simple”, it serves as a “bridge” connecting the cold source and servers—an irreplaceable link made for AI data center thermal management. Its importance is mainly reflected in three dimensions:
1. Ensuring Uniform Heat Dissipation of Servers and Avoiding “Local Overheating”
Core components of AI servers, such as GPUs and CPUs, are extremely sensitive to temperature. Insufficient cooling fluid flow will cause component temperatures to soar above 80℃, triggering frequency reduction or even shutdown. Excessive flow, on the other hand, leads to energy waste. By evenly distributing flow, the water distributor (Manifold)—made for balancing server cooling needs—ensures each server receives a stable supply of cooling fluid, avoiding the problem of “some servers overheating while others have excessive flow” due to flow differences, and ensuring the stable operation of the entire AI cluster.
2. Simplifying System Structure and Reducing Operation and Maintenance Costs
Without a water distributor (Manifold), the cold source would need to lay independent pipes directly for each server. 100 servers would require 100 independent pipes, which not only increases pipe material costs but also results in cluttered pipelines in the equipment room, making it difficult to troubleshoot faults during operation and maintenance. Through its “main pipe + branch ports” structure made for simplifying pipeline layout, the water distributor (Manifold) simplifies 100 pipes into 1 main pipe + 100 branch ports, reducing material usage while allowing maintenance personnel to quickly locate leak points or adjust flow, lowering the difficulty and cost of operation and maintenance.
3. Adapting to Computing Power Expansion Needs and Enhancing System Flexibility
The computing power demand of AI data centers usually continues to grow, and the number of servers may expand from 50 initially to 100 or more. The design of water distributors (Manifolds) can reserve additional branch ports (e.g., 100 ports designed initially, with only 50 activated)—a design made for adapting to future expansion. During later expansion, there is no need to re-lay the main pipe; new servers can be connected by activating the reserved ports, significantly shortening the expansion cycle and reducing transformation costs.
IV. Future Technological Outlook of Water Distributors (Manifolds): Evolving Towards “Intelligence, Efficiency, and Integration” Made for Higher Demands
As the power density of AI data centers continues to increase (possibly exceeding 200kW per rack in the future) and liquid cooling systems move towards “refined management”, the technology of water distributors (Manifolds) will advance in the following three directions—evolutions made for meeting higher performance demands:
1. Intelligence: From “Passive Distribution” to “Active Regulation”
Future water distributors (Manifolds) will integrate more precise sensing and control modules made for intelligent regulation. By installing micro-flow sensors and electric control valves at each branch port, real-time data on cooling fluid flow and temperature of each server can be collected and linked to the data center’s thermal management system (such as a DCIM system). When a server’s temperature rises due to increased computing load, the system can automatically increase the flow at that port; when the server is under low load, the flow is automatically reduced to achieve “on-demand distribution” and further reduce the energy consumption of the cold source. This intelligent upgrade is made for adapting to the dynamic cooling needs of high-power AI clusters.
2. Material Upgrades: Adapting to Higher Pressure and More Complex Coolants
As the pressure of liquid cooling systems may increase to over 2.5MPa (to meet long-distance transportation needs) and new coolants (such as nanofluids, fluorinated liquids) are applied, water distributor (Manifold) materials will be upgraded to “higher strength and stronger corrosion resistance”—an upgrade made for harsher operating conditions. For example, titanium alloy materials (50% stronger than stainless steel and more corrosion-resistant) may be used, or ceramic coatings may be sprayed on the inner walls of stainless steel to enhance tolerance to special coolants and extend the service life of water distributors (Manifolds).
3. Integration: Merging with Other Components to Simplify the System
Future water distributors (Manifolds) may no longer be independent components but integrated with components such as “filters, exhaust valves, and temperature sensors” to form an “integrated flow distribution unit”—a design made for system simplification. Filters can pre-filter impurities in the cooling fluid to prevent blockage of server heat dissipation channels; exhaust valves can automatically discharge air from the pipes to prevent air resistance from affecting flow; temperature sensors can directly monitor the temperature of the cooling fluid, reducing the need for additional sensor installation. This integrated design will further simplify the structure of the liquid cooling system and improve overall reliability.
Conclusion
In the era of “computing power is king” for AI data centers, thermal management is key to ensuring the release of computing power. As the “flow commander” made for AI data center thermal management systems, the water distributor (Manifold)’s technological iteration and performance improvement will directly affect the efficiency, stability, and cost of data centers. From the current “precision distribution” to the future “intelligent regulation”, although the water distributor (Manifold) is small, it undertakes the important mission of the continuous growth of AI computing power. Its development will also epitomize the evolution of data center liquid cooling technology from “functional” to “high-performance and efficient”—a evolution always made for supporting the advancement of AI computing.
