The water pump is one of the essential accessories of the engine. Most of the water pumps are installed in the middle of the cooling system, and a few water pumps are installed on the top of the engine. Early automobile engines did not have a water pump. The liquid cooling medium used at that time was pure water, sometimes mixed with wood alcohol to prevent freezing. The circulation of cooling water completely relies on the natural phenomenon of heat convection. But soon, a water pump was added to the cooling system to allow the cooling water to flow more quickly.
The water pump is generally driven by the V-belt driven by the crankshaft of the engine. The drive belt surrounds the crankshaft pulley and the water pump pulley. The rotation of the crankshaft drives the water pump shaft to follow the operation, and the water pump shaft drives the impeller to rotate, thereby realizing the conversion of mechanical energy into hydraulic energy.
The impeller is the core component of the pump, and the movement of the impeller itself only rotates with the shaft. However, due to the action of the blades, the movement of the liquid in the impeller is very complicated; first, it makes implicated motion with the rotation of the impeller, and second, it is continuously thrown out of the rotating impeller under the drive of the blade, that is, it moves relative to the impeller. Therefore, the outer diameter of the impeller, the height and angle of the impeller blades, and the gap with the water pump casing directly affect the performance of the water pump.