Steam enters and leaves a horizontal 1D pipe steadily at a constant speed with the specific enthalpy to be 4000 kJ/kg and 1500 kJ/kg respectively. Assuming a mass flow rate of 0.5 kg/sec and If there is no significant change in potential energy from inlet to exist, determine the rate of heat transfer between the pipe and its surroundings.

The rate of heat transfer between pipe and its surrounding is found to be 1250 KW

Explanation:

Assuming no significant change in potential energy. When we apply the first law of thermodynamics to the given system of 1-D pipe, we get the following expression:

Q = m (h₁ - h₂)

where,

Q = Heat Transfer between pipe and surrounding = ?

m = mass flow rate of steam = 0.5 kg/sec

h₁ = Specific Enthalpy of steam at entrance = 4000 KJ/kg

h₂ = Specific Enthalpy of steam at exit = 1500 KJ/kg

Therefore, using these values in the equation, we get the value of heat transfer:

Q = (0.5 kg/sec) (4000 KJ/kg - 1500 KJ/kg)

Q = 1250 KW