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Discharge (Q) of a centrifugal pump is given by (where D = Diameter of impeller at inlet, b = Width of impeller at inlet and Vf = Velocity of flow at inlet)
Two centrifugal pumps P and R are available for use in a pipe flow system and their head-discharge characteristics are as follows. Pump P Pump R Discharge (cumecs) Head (m) Discharge (cumecs) Head (m) 0 40 0 45 0.12 35 0.14 40 0.2 28 0.24 35 0.3 18 0.3 28   The following statements (S1, S2, and S3) pertain to the head and discharge values during actual operation. Neglect losses in the system. Which of the following statements are correct? S1: When the two pumps P and R are connected in parallel, the discharge is 0.36 cumecs corresponding to a head of 35 m. S2: When the two pumps P and R are connected in parallel, the discharge is 0.36 cumecs corresponding to a head of 70 m. S3: When the two pumps P and R are connected in series, the discharge is 0.3 cumecs corresponding to a head of 46 m.
Consider the following statements pertaining to centrifugal pumps: 1. The inlet to the impeller of a centrifugal pump is always axial, while the outlet may be radial or inclined. 2. The impeller may be shrouded on both sides with an eye at the center and vanes curved backward. 3. Impeller of double-entry type has a balanced radial thrust. 4. Un-shrouded and part-shrouded impeller are used only where high efficiency is unimportant. Which of these statements are correct?
Consider a centrifugal pump having a specific impeller diameter, fixed impeller speed pumping a liquid of constant density at a particular discharge capacity. With decrease in the capacity of the pump, the __________ decreases.
Which of the following statements are correct? 1) Velocity compounded impulse turbine gives less speed and less efficiency. 2) For an ideal centrifugal compressor, the pressure produced depends on impeller velocity and diameter. 3) While flowing through the rotor blades in a gas turbine, the relative velocity of gas continuously decreases. 4) While flowing through the rotor blades in an axial flow compressor, the relative velocity of air continuously decreases.
A centrifugal pump which circulates a hot liquid metal at 500 degree Celsius is driven by a 3600 rpm electric motor. The motor is coupled to the pump impeller by a horizontal steel shaft of dia 25 mm. Let us assume the motor temperature as 60 degree Celsius with the ambient air at 25 degree Celsius, what length of shaft should be specified between the motor and the pump? It may be presumed that the thermal conductivity of the shaft material is 35W/m K and that the convective film coefficient between the steel shaft and the ambient air is 15.7W/square m K
একটি পানিপূর্ণ কুয়ার গভীরতা 20m ও ব্যাস 2 m. কুয়াটিকে পানি শূণ্য করার জন্য 5 HP এর একটি পাম্প লাগানো হল। অর্ধেক পানি তোলার পর পাম্পটি নষ্ট হয়ে গেল। বাকি পানি তোলার জন্য একই ক্ষমতা সম্পন্ন আর একটি পাম্প লাগানো হল। প্রথম পাম্প দ্বারা সম্পাদিত কাজের পরিমান নির্ণয় কর।(The depth and diameter of a water filled well are 20 m and 2 m respectively. An engine of 5 HP is attached to pump out the water. The pump was ruined after emptying half of the water. Then another pump of same capacity was attached to pump out rest of the water. Determine the work done by first pump.) 
N.P.S.H. requirements could be _________ by utilizing an inducer, a low head, axial flow impeller utilized in front of the impeller of a centrifugal pump.
Discharge of a centrifugal pump is (where N = Speed of the pump impeller)
The peripherial velocity at inlet of a centrifugal pump having inlet diameter of 25 cms and rotating at 950 rpm is __________ m/sec.