Question

THERMO

Question 1

1. A pump steadily delivers 13.7 kg/s of water at the conditions given below. Calculate the pump power (hp).

   There is no heat transfer from the pump to the surroundings (i.e., adiabatic conditions).

   Pump Inlet Temperature = 20^oC

   Pump Inlet Pressure = 170 kPa

   Pump Inlet Diameter = 11.4 cm

   Pump Inlet Elevation = 20 m

   Pump Exit Temperature = 20^oC

   Pump Exit Pressure = 581 kPa

   Pump Exit Diameter = 5 cm

   Pump Exit Elevation = 20 m

Question 2

1. A well-insulated, full, water tank containing 123 kg of water initially at 44.7^oC is being supplied with 24.3^oC water at a rate of 4 kg/min. Water is exiting the tank at the same flow rate so that the mass of water in the tank remains constant. Circulation in the tank keeps the water at a uniform temperature. The specific heat of the water is given as C = 4.2 kJ/kg-K. Determine the temperature of the tank (^oC) after 6.6 minutes.

   Note: The energy of water in the tank is given as: E = m_cv*C*T

   The solution for an equation of the form: a*dT/dt + T + b = 0     is   

   T(t) = k1*exp(-t/a) + k2

   For this problem, the given constraints are:

   T(t=0) = T_initial

   T(t=infinity) = T_inlet

   Hint: Use the given constraints to determine the constants k1 and k2

Answer 1

See the attached images for the solution.

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