(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Steam flows through an uninsulated pipe at 0.5 kg/s, entering at 5 bar, 440 C and exiting at 3 bar, 320 C. How much energy is lost from the steam per hour?

2. Relevant equations

Which terms in the energy eqn can drop out? I'm having trouble with that.

Is there only one W?

3. The attempt at a solution

Starting w/ the full energy eqn:

de/dt = Q - W_ + (m_i)[u_i + (p_i)(v_i) + (v_i)^2 + g*z_i] - (m_e)[u_v + (p_e)(v_) + (v_e)^2 + g*z_e]

where Q = vol. flow rate

W = work rate

m = mass flow rate

subscript e = out

subscript i = in

v = velocity

u = specific internal energy

p = pressure

So z_i = z_e = 0

Q = mv = (0.5)(0.6548) = 0.3274?

**Physics Forums | Science Articles, Homework Help, Discussion**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Thermodynamics: Control Volume analysis using energy

**Physics Forums | Science Articles, Homework Help, Discussion**