Finding enthalphy for tee junction

Dhanik desai · April 29, 2020, 02:39

I am simulating tee junction, 2 inlets and 1 outlet, hot inlet temp is 36 c & cold inlet temp is 19 c, hot inlet velocity is 3 m/s and cold inlet velocity is 12m/s

By simulation, I get 2559.11 J/kg enthalpy at an outlet , How to find enthalpy at an outlet by equation

Formula is
h(mixing)=m(hot)*h(hot)+m(cold)*h(cold)/m(total)

How to find h hot and h cold?
Material is air

LuckyTran · April 29, 2020, 06:05

You need an equation of state. If you are doing a simulation of some sort, the equation of state is a user setting.

Dhanik desai · April 29, 2020, 06:28

Hi sir , thanks for reply I want to find h hot and h cold manually

agd · April 29, 2020, 09:58

You will need to use the equation of state to evaluate the enthalpy by hand. For this you need thermodynamics, but here's a hint. For air at the temperatures you are working with the enthalpy can be expressed to a high degree of accuracy as h = Cp * T, where Cp is the specific heat at constant pressure.

Dhanik desai · May 1, 2020, 06:53

Thank you, sir, I did it with Cp *delta t where Tref is 298.15K

April 29, 2020, 02:39	Finding enthalphy for tee junction	#1
Dhanik desai New Member dhanik Join Date: Oct 2019 Posts: 10 Rep Power: 7	I am simulating tee junction, 2 inlets and 1 outlet, hot inlet temp is 36 c & cold inlet temp is 19 c, hot inlet velocity is 3 m/s and cold inlet velocity is 12m/s By simulation, I get 2559.11 J/kg enthalpy at an outlet , How to find enthalpy at an outlet by equation Formula is h(mixing)=m(hot)h(hot)+m(cold)h(cold)/m(total) How to find h hot and h cold? Material is air Last edited by Dhanik desai; April 29, 2020 at 06:28.

April 29, 2020, 06:05		#2
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,762 Rep Power: 66	You need an equation of state. If you are doing a simulation of some sort, the equation of state is a user setting. Dhanik desai likes this.

April 29, 2020, 09:58		#4
agd Senior Member Join Date: Jul 2009 Posts: 358 Rep Power: 19	You will need to use the equation of state to evaluate the enthalpy by hand. For this you need thermodynamics, but here's a hint. For air at the temperatures you are working with the enthalpy can be expressed to a high degree of accuracy as h = Cp * T, where Cp is the specific heat at constant pressure. Dhanik desai likes this.

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April 29, 2020, 06:28		#3
Dhanik desai New Member dhanik Join Date: Oct 2019 Posts: 10 Rep Power: 7	Hi sir , thanks for reply I want to find h hot and h cold manually

May 1, 2020, 06:53		#5
Dhanik desai New Member dhanik Join Date: Oct 2019 Posts: 10 Rep Power: 7	Thank you, sir, I did it with Cp *delta t where Tref is 298.15K