The power transmitted by the prime mover to the pump shaft cannot be fully converted to effective power, that is, it cannot be used to increase the energy of the liquid. Since part of the energy is consumed during the rotation of the pump shaft, a part of the energy is lost in the pump, so the effective power of the pump is always less than the shaft power. Energy loss and efficiency of BRY heat transfer oil circulation pump The power transmitted by the prime mover to the pump shaft cannot be fully converted to effective power, that is, it cannot be used to increase the energy of the liquid. Since part of the energy is consumed during the rotation of the pump shaft, a part of the energy is lost in the pump, so the effective power of the pump is always less than the shaft power.
According to the BRY heat transfer oil circulation pump energy loss form can be divided into: mechanical loss, volume loss and oil loss.
1. Mechanical loss and mechanical efficiency Mechanical loss consists of two parts: one is the friction loss between the pump shaft and the bearing and the shaft sealing device; the other is the wheel resistance loss, also known as the disc friction loss, which is the original pump casing filled with liquid. Friction loss between the outer surface of the impeller and the liquid when rotating inside.
In the mechanical loss, the wheel resistance loss accounts for a large proportion, while the bearing shaft seal device has a small friction loss. Botaibang uses mechanical efficiency ηm to represent the magnitude of mechanical loss. Mechanical efficiency is the ratio of residual power to shaft power after mechanical loss of shaft power Pe, ie:
Pm in the formula - the power consumed due to mechanical losses.
Theory and practice show that reasonable reduction of the outer diameter of the impeller, increase of the impeller speed, and reduction of the surface roughness of the wheel cover can improve the mechanical efficiency of the pump. If the pump shaft is mechanically sealed, the friction loss of the shaft seal is small. If the packing is sealed, it should be noted that the packing gland should not be over-tightened. The mechanical efficiency of the BRY heat transfer oil circulation pump is generally 90%~97%.
2. Volume loss and volumetric efficiency When the BRY heat transfer oil circulating oil pump is running, the liquid pressure in the pump body is different, and there are high pressure zones and low pressure zones. Due to the need of the mechanism, there are many gaps inside the pump body. When the pressure before and after the gap is different, some liquids must have a high pressure zone flowing low pressure zone. Although this part of the liquid obtains energy but is not effectively utilized, it circulates in the pump. It is consumed to overcome the gap resistance. A part of the liquid is also leaked from the shaft seal after obtaining energy, so the actual flow rate qv of the pump is smaller than the theoretical flow rate qvth.
The volumetric efficiency ηv is used to indicate the volume loss, which is the ratio of the power after volume loss to the power without volume loss, ie:
The volumetric efficiency ηv of the BRY heat transfer oil circulating oil pump is generally 90% to 95%.
For a given BRY heat transfer oil circulating oil pump, to increase the volumetric efficiency ηv, it is necessary to reduce the leakage amount, and the annular area of ​​the seal gap can be reduced or the gap resistance of the seal ring can be increased. The BRY heat transfer oil circulating oil pump in operation should regularly check the wear of the seal ring and replace it in time, otherwise the volumetric efficiency will be reduced. Botou Taibang Pump & Valve Manufacturing Co., Ltd. 3. Oil loss and oil efficiency The liquid has friction loss when flowing through the overcurrent parts such as the impeller, and there is impact loss when the flow velocity and direction of the liquid change. These losses consume a portion of the energy, which is often referred to as oil loss.
(1) The frictional resistance loss caused by the overcurrent component along the frictional loss of liquid passing through the flow-through chamber, the impeller, the guide wheel, and the like. Since the friction loss along the path is proportional to the square of the flow rate, and the flow rate is proportional to the flow rate, the friction loss along the path is proportional to the square of the flow.
(2) Impact loss A resistance loss occurs when the magnitude and direction of the liquid flow velocity change. In the design condition, since the flow direction is consistent with the blade direction, the impact loss is small and close to zero. When the flow rate is greater than or less than the design condition, the impact loss is gradually increased due to the change in the direction of the liquid flow.
The total oil loss of the BRY heat transfer oil circulating oil pump is the above two items.
The oil efficiency is the ratio of the power after oil loss to the power without oil loss, expressed in accordance with ηh. The size of ηh is related to the construction of the BRY heat transfer oil circulation pump, which is generally 70% to 90%.
In order to improve the oil efficiency, the shape and blade form of the impeller flow path should be reasonably determined, and the liquid flow rate should be changed as gently as possible to prevent vortices and dead angles and reduce the surface roughness of the overcurrent components.
4. The total efficiency η of the BRY heat transfer oil circulating oil pump is equal to the ratio of the effective power P to the shaft power Pe, namely:
The efficiency of the BRY heat transfer oil circulating oil pump is related to the specific speed of the BRY heat transfer oil circulating oil pump, and also depends on the flow rate and structure of the pump. When the single-stage single-suction heat-conducting oil circulating oil pump delivers normal temperature and clear oil and the specific speed ns=120~210, the efficiency value can be found according to the flow rate.
The efficiency of the BRY heat transfer oil circulation pump is an important technical and economic indicator, which indicates the performance of the pump and the degree of use of the prime mover. Increasing the efficiency of the BRY heat transfer oil circulation pump involves problems such as pump design, manufacturing, installation, operation, etc., and must be fully considered in order to achieve efficiency.
Product/
Http://news.chinawj.com.cn
Editor: (Hardware Business Network Information Center) http://news.chinawj.com.cn
Angel Valve,Shower Handle Leaking,Shower Handle Hard to Turn,Removing Shower Handle
kaiping aida sanitary ware technology co.,ltd , https://www.aidafaucet.com