Head and flow rate of the cooling water pump in the cooling water tower
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As shown in the attached diagram, the horizontal water pump has a power of 11 kW, a head of 14.6 meters, and a flow rate of 160 cubic meters per hour. The pump’s rotation speed is 1470 rpm; its inlet diameter is DN125, while its outlet diameter is DN100. The vertical height from the pump’s outlet to the water outlet of the cooling tower’s distributor is approximately 10 meters. The diameter of the pipeline that carries water from the pump to the bottom inlet of the water tower is 6 inches. The total length of the pipeline connecting the pump’s outlet to the cooling water outlet in the tower is about 20 meters, of which 10 meters are horizontal and 10 meters are vertical. There are 5 6-inch elbows in this pipeline. In addition, there are two points along the internal water pathway from the tower’s inlet assembly to the distributor’s outlet where the direction of the water flow changes. Referring to the curve graph, when the head is 14.6 meters, the flow rate of this water pump is approximately 160 cubic meters per hour; at a head of 14 meters, the flow rate is about 170 cubic meters per hour. Under such installation conditions, what will be the actual flow rate in the pipelines while the water pump and water tower are in operation? The standard circulation volume for the water tower is 150 cubic meters per hour. Can it be achieved? If it can’t be achieved, how many cubic meters per hour can it roughly reach? I would also appreciate it if professionals could offer some guidance. Thank you!
The water level in the tank is higher than the location where the pump is installed; the pump is situated near the tank. The pipe running from the tank to the pump has a diameter of DN200, and it narrows to DN125 at the point where it connects to the pump’s inlet. The pump’s outlet has a diameter of DN100, and it narrows to DN150 before connecting to the pipe that supplies water to the cooling system, leading to the cooling tower. The return pipe from the cooling tower goes straight downward, allowing the water to flow back to the tank due to gravity. When the pump stops, no water remains inside the cooling tower
I’m not a professional designer; I’m just interested in how things work :) I’m asking out of curiosity – is your question related to design issues or to usage problems? Thank you! :)
1. Pipeline flow rate… It’s not very meaningful to try to determine the ideal water volume required by the equipment in order to consider the pipeline flow rate. 2. The pipe outlet has a diameter of DN100 = 4”; the flow rate should be around 30 T/H. Using such drawings indicates that the fluid velocity is high but the flow rate is insufficient. To achieve a flow rate of 150 M3/H, the pipe diameter should be 10”, or DN250. 3. Your HP is 14.6; basically, no one would choose a value that’s exactly this high. With a margin for safety, it’s recommended to use a value between 18 and 22