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In the operation and maintenance philosophy of "IHPC" regarding the severe "water hammer effect" that the secondary circuit of the CDU (coolant distribution unit) in the liquid cooling system may face. The following is a summary of the technical analysis and protection strategies adopted in the operation and maintenance philosophy of " IHPC":

I. Analysis of Water Hammer Effect in Liquid Cooling Systems

Hydraulic shock refers to the phenomenon in pressure pipelines where a sudden change in fluid velocity (such as a valve closing abruptly or a pump stopping abruptly) instantly converts kinetic energy into pressure energy, generating a destructive shock wave that propagates along the pipeline. In the high- density liquid-cooled data center of 2026, the CDU secondary loop is responsible for precisely delivering coolant to the high-value GPU cold plates. Any hydraulic shock could damage precision sensors, rupture pipelines, or even cause cold plate leaks.
The hydraulic shock in the secondary circuit of the CDU mainly originates from the following three mechanisms:
1.Hydraulic shock:
oCause: The most common type, usually occurring when an electric valve or check valve closes rapidly. In a high-speed liquid cooling circuit, if the valve closes faster than the shock wave propagation speed, the fluid impacting the valve will generate a pressure wave of up to several thousand psi.
oRisk: This impact force is equivalent to a hammer blow of hundreds of pounds striking the pipe wall, which may cause the joint to loosen or damage the differential pressure sensors (DP Sensors) inside the CDU.
2.Thermal shock:
oCause: When air bubbles (such as those introduced by cavitation or leakage) are compressed in a liquid or come into contact with coolant, they collapse instantaneously. The collapse of the bubbles causes the surrounding fluid to rapidly fill the vacuum, generating micro-explosive shocks from all directions.
oRisk: Particularly dangerous in two-phase flow or air-incorporated systems, it can lead to pitting and erosion inside the pipe wall.
3.Differential shock:
oCause: When gas and liquid coexist, the liquid column (Slug) is accelerated and pushed by the pressure difference before and after, and hits the pipe bend or valve at high speed like a piston.
oRisk: The flow rate can increase dramatically, resulting in extremely high impact force, which often occurs in systems with incomplete venting of the pipeline.

II. Protection Strategies for IHPC

To address the aforementioned risks, IHPC's 2026 IDC strategy employs multi-layered technical and procedural safeguards to ensure the "common maintainability" and "zero-accident" goals of the liquid cooling system.
1.Two-Stage Closing Strategy
To strike a balance between "rapidly isolating faults" and "preventing water hammer damage," IHPC employs optimized valve control logic:
•Technical principle: The valve closing stroke is programmed into two stages.
oPhase 1 (Rapid Zone): The first 80% of the valve cross-sectional area will be quickly closed to block most of the flow.
oSecond stage (buffer): The remaining 20% of the cross-sectional area is then slowly closed.
•Benefits: This design utilizes a damping mechanism to gradually reduce the mass flow rate, effectively eliminating pressure peaks caused by sudden stops and preventing shock waves from oscillating back and forth in the loop.
2.Flywheel Inertia Pumps
For the most dangerous " pump disconnection " scenarios (such as sudden power outages), IHPC has implemented physical inertial protection:
•Technical principle: Inertia wheels/flywheels are installed on the circulating pump.
•Operating mechanism: When the power is suddenly interrupted, the kinetic energy stored in the flywheel will drive the pump impeller to continue rotating, causing it to slowly decelerate (spindown) rather than come to an instantaneous stop.
•Benefits: This maintains fluid momentum in the pipeline, prevents "water column separation" and subsequent impact caused by a sudden drop in flow velocity, and smoothly transitions pressure changes.
3.Supplementary protective measures
In addition to the core technologies mentioned above, IHPC has also integrated the following protective measures to build a complete defense network:
•Inline Elasticity: Uses truncated buffers in low-pressure or sensitive areas. HDPE (high-density polyethylene) or LDPE pipes. They utilize the elastic expansion of the material itself to absorb the energy of pressure waves, acting as passive shock absorbers.
•Air cushioning: Water hammer arrestors or expansion tanks are installed at the ends of pipelines or critical points. These devices are filled with gas, which can compress and absorb the energy of backflow impacts.
•Strict flow rate control: Operating procedures strictly limit fluid velocity to below 1.5 m/s (4.9 ft/s) to reduce kinetic energy at the physical source, thereby reducing potential water hammer damage.

This comprehensive protection strategy demonstrates how IHPC, by combining precision control (two-stage valves), physical inertia (flywheel), and material properties (flexible piping), can completely eliminate the mechanical risks of liquid cooling systems while ensuring the cooling needs of high-density AI computing power .