How is the operating point of a pump and piping system determined?
The point at which a pump operates in a given piping system depends on the flow rate and head loss of that system. For example, in Figure 10, the operating point for the centrifugal pump in the original system is designated by the intersection of the pump curve and the system curve (hLo).
What is a pump system curve?
A system curve, as shown in Figure 2, is a graphical representation of the pump head that is required to move fluid through a piping system at various flow rates. The system curve helps quantify the resistance in a system due to friction and elevation change over the range of flows.
What is end of curve operation for pump?
Every centrifugal pump operates along its curve and every curve has a staring point, shut-off or zero flow, and an end point, the end-of-curve or the maximum flow achievable without over loading the motor.
What is the effect of cavitation in pumps?
Simply defined, cavitation is the formation of bubbles or cavities in liquid, developed in areas of relatively low pressure around an impeller. The imploding or collapsing of these bubbles trigger intense shockwaves inside the pump, causing significant damage to the impeller and/or the pump housing.
How do you know if a pump is cavitating?
A: If the pump is cavitating, it will typically vibrate, deliver less flow and make a noise that sounds like marbles going through the pump. The sound may start out at a low level and increase in intensity over time as material is chipped away and the surface of the parts becomes rougher.
What are the signs of cavitation?
What are the symptoms of cavitation? The obvious symptoms of cavitation are noise and vibration. When bubbles of vapour implode they can make a series of bubbling, crackling, sounds as if gravel is rattling around the pump housing or pipework.
What is the purpose of draft tube?
The draft tube is a conduit which connects the runner exit to the tail race where the water is being finally discharged from the turbine. The primary function of the draft tube is to reduce the velocity of the discharged water to minimize the loss of kinetic energy at the outlet.
What is the use of Francis turbine?
A Francis turbine is a large rotary machine that works to convert kinetic and potential energy into hydroelectricity. These modern equivalents of the water wheel have been used for over 135 years for industrial power generation, and more recently hydropower energy generation.
Where is Kaplan turbine used?
Kaplan turbines are widely used throughout the world for electrical power production. They cover the lowest head hydro sites and are especially suited for high flow conditions.
What is the speed ratio of Kaplan turbine?
A Kaplan turbine develops works at 195 rpm under 12 m head and with an overall efficiency of 85 percent. The geometric and flow parameters are as follows: speed ratio (based on outer diameter) is 2.0, flow ratio is 0.63, and diameter of the boss is 35 percent of external diameter of the runner.