- #1

aznkid310

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## Homework Statement

Air enters a car radiator at 50 km/hr, 25 C. The radiator is 1 m2 facial area. 2 kg/s of water enters the radiator from the engine at 10 bar, 200 C and leaves at 10 bar, 180 C. What is the temperature of the air as it leaves the radiator?

## Homework Equations

I did an energy balance for air and then for water, but I am not sure which terms can be ignored. After i obtain these eqns, i can set them equal to each other and solve for T (from

Q =m(c_p)(Change in T))?

## The Attempt at a Solution

For Air: W = Q + (m)(h_in + [(v_in)^2]/2 +g*z_in - h_out - [(v_out)^2]/2 -g*z_out)

m = mass flow rate

Q = heat flow rate

W = work flow rate

h = enthalpy

v = velocity

I assume W, z_in, z_out are zero and also that m_in = m_out

So i get Q = m(h_in - h_out + [(v_in)^2]/2)

For water:

Q = m(h_out - h_in) = (0.2)(762.8 - 2827.9) = -2065.1 kW