A gas initially at 1.5 bar pressure, 0.15m 3

volume and 300 K was compressed

polytropically (pv 1.25 = constant) to 15 bar pressure. Determine the change

in entropy. Also work out the approximate entropy change obtained by

dividing the heat transferred by the mean absolute temperature during compression.

Take cp = 1.04 kJ / kg K and cv = 0.745 kJ / kg K.​

The quality is zero at a)-the saturated vapour state b)-the saturated liquid state c)-the saturated liquid-vapour mixture state d)-none of the states in the other answers

Apreheater involves the use of condensing steam at 100°c on the inside of a bank of tubes to heat air that enters at 1 atm and 25°c. the air moves at 5 m/s in cross flow over the tubes. each tube is 1 m long and has an outside diameter of 10 mm. what is the minimum value of nl needed to achieve an outlet temperature of t 75 c? what is the corresponding pressure drop across the tube bank?

Consider a power plant with water as the working fluid that operates on an ideal rankine cycle. it has a net power output of 45mw. superheated steam enters the turbine at 7mpa and 500°c (h=3411.4 kj/kg; s=6.8 kj/kg k) and is cooled in the condenser at a pressure of 10 kpa by running cooling water from a lake through the tubes of the condenser at a rate of 2000 kg/s. (a) show the cycle on a t-s diagram (a right schematic is fine - you do not need to calculate the temperatures at each point); (b)-determine the work done by the turbine and the pump in kj/kg; (c)-the mass flow rate of water used by the power plant; (d)-the thermal efficiency of the cycle; (e)-the temperature rise of the cooling water. assume the cooling water is incompressible with cp 4.18 kj/kg°c.