Engineering Thermodynamics homework help, water cooled air cooler

[elecone]

Homework Statement

A water cooled air cooler (WCAC) has the following conditions:

Air cooler:
mass flow rate: 10kg mins^-1
entry air temp: 300 degrees c
entry air pressure: 2 bar
entry pipe diameter: 0.1m
velocity of air on exit: 25 ms^-1

Water cooler:
mass flow rate: 10 kg min^-1
water temp increase by 50 degrees c

the heat transfer from air to water has an efficiency of 100%

Air Cp = 1.004 KJ Kg^-1K^-1
Air Cv = 0.717 KJ Kg^-1K^-1
Water specific heat = 4.187 KJ Kg^-1K^-1

What is the temperature of the air as it leaves the WCAC

Relevant Equations

pV=mRT
R=cp/cv
ṁ=pAC

I'm not looking for someone to tell me the answer, just help steer me in the right direction.

I feel like I need to find the air density or air velocity at entry to proceed, but I'm unsure

any help and guidance is greatly apricated!

 

[elecone]

no takers?

 

[Chestermiller]

From the water data, what is the heat load (the rate of transfer of heat to the water)? If you apply the open system (control volume) version of the first law of thermodynamics to the air side of the heat exchanger, what do you get for the relationship between the mass flow rate of air, the enthalpy change per unit mass of the air, and the heat load?

 

[Delta2]

If you apply the open system (control volume) version of the first law of thermodynamics to the air side of the heat exchanger, what do you get for the relationship between the mass flow rate of air, the enthalpy change per unit mass of the air, and the heat load?

Excuse my ignorance but where I can find a statement of the open system version of the 1st law that is suitable for application to this problem. I tried wikipedia but without success , the section for open systems there seems not well written.

 

[Chestermiller]

Excuse my ignorance but where I can find a statement of the open system version of the 1st law that is suitable for application to this problem. I tried wikipedia but without success , the section for open systems there seems not well written.

Fundamentals of Engineering Thermodynamics, Moran et al, available on line

Introduction to Chemical Engineering Thermodynamics, Smith and van Ness

Chemical Engineers' Handbook, Perry et al

http://www.rshanthini.com/yahoo_site_admin/assets/docs/ThermoChap09.20063703.pdf