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Most typically it is due to an obstruction in the discharge piping, or air collecting in the top of the pump. Less obvious would be interstage seal leakage, casing leakage, low pressure seal leakage or suction line air induction. Or if a cross connected labyrinth ring is used in the stuffing box this line could have gotten plugged, allowing air to seep in. Improperly positioned suction head could also reduce output, for hot feedwater applications, a D/A or feed tank should be positioned to maintain a positive pressure sufficient enough to prevent steam flashing in the eye of the pump. Seal rings on the impellers could be worn as well.
Check to make sure the suction and discharge valves are fully open, calculate the suction head and compare it to the needed suction head to prevent steam flashing, (Pressure/temperature columns in the steam tables). For instance a 250 F water temperature requires a suction head of, at least, +80 feet ( 20 psig) to prevent flashing. If the suction pressure is too low, increase it or cool the water to a reasonable temperature.
Open the casing vent slowly to expel any air in the pump. If this doesn't work, check for leakage or damaged pump parts, this may require disassembly.
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What happens to flow and pressure if the rotational speed of a centrifugal fan is doubled?
it gets faster
Is there a pumping system which variable speed drive is not recommended?
Most centrifugal chillers require a constant water flow, therefore a VFD would not be of any use.
In a fixed displacement pump flow is directly related to speed or pressure?
speed
If you double the speed of centrifugal pump?
Centrifugal pumps generally obey what are known as the pump laws. These laws state that the flow rate or capacity is directly proportional to the pump speed; the discharge head is directly proportional to the square of the pump speed; and the power required by the pump motor is directly proportional to the cube of the pump speed.
What are characteristics of centrifugal pump?
centrifugal pump is that machine which converts the mechanical energy into pressure energy . 1. it produces th pressure energy by applying the centrifugal force. 2. flow in it is radial outward direction. 3.the pressure head at the outlet is more than the at inlet, so fluid can be lifted to very high .level 4.in case of centrifugal pump, discharge is proportional to speed in r.p.m power is proportional to ( speed in r.p.m)^3 head is proportional to ( speed in r. p.m)^2 5. it is subjected to cavitation.
What is the form of flow in volute casing after the impeller in centrifugal pump?
rotational
Why centrifugal pump is not called a positive displacement type of pump?
A positive displacement pump causes a fluid to move by trapping a fixed amount of it then forcing (displacing) that trapped volume into the discharge pipe. Centrifugal pumps impart pressure to the fluid, to cause a pressure differential and cause flow, but even if the outlet is sealed, the pump can continue to run because it hasn't trapped the fluid. When no flow is occurring, a centrifugal pump acts like a propeller spinning in the water. If flow is stopped on a line that a positive displacement pump is supplying flow to, the pump is forced to stop since the trapped fluid prevents it from moving any more fluid.
The frontal area of a centrifugal compressor as compared to axial flow compressor is larger or smaller?
the frontal area of a centrifugal compresor is more as compared to axial flow compressor for a given air flow. And for this reason axial compressors are being used in aircraft engines.
What is the difference of an axial flow and centrifugal compressor?
The centrifugal flow compressor has a single or two stage unit using an impeller. The axial flow compressor is a multi-stage unit using alternate rows of rotating (rotor) blades and stationary (stator) vanes.
What is the function of the impeller in a centrifugal pump?
Impeller make the flow has velocity in a centrifugal pump. The purpose of pump is increasing the pressure. The flow has velocity envergy via impeller and the energy change to pressure energy in diffuser.
Which is true when a radial compressor and an axial compressor with equal air flow and revolution are compared?
I don't understand the question. It would appear that you wish to compare a centrifugal compressor and an axial flow compressor operating at the same speed and delivering equal flow rates. What is the process fluid? What is the question? Is the "equal air flow" the mass flow rate? At what pressure differential would you like to consider these machines? What is it that you wish to compare? Is it weight, frontal area, mechanical efficiency, overall diameter, length, delivery temperature, input power or what?
What has the author N Suryavamshi written?
N. Suryavamshi has written: 'Unsteady flow field in a multistage axial flow compressor' -- subject- s -: Centrifugal compressors, Unsteady flow, Flow distribution
