Energy balance

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 July 5, 2004, 00:39 Energy balance #1 Julie Polyakh Guest   Posts: n/a Hello, Does somebody know how to calculate energy balance at two cross sections (not inlets or outlets)? Best Regards, Julie

 July 5, 2004, 03:22 Re: Energy balance #2 Richard Guest   Posts: n/a In v3.20 there's a new thing called internal boundaries which can do this.

 July 5, 2004, 03:40 Re: Energy balance #3 Julie Polyakh Guest   Posts: n/a And what about v3.150A?..

 July 5, 2004, 06:15 Re: Energy balance #4 Thomas Guest   Posts: n/a what about calculating the enthalpy difference (cp *dT) between these two cross sections?

 July 5, 2004, 08:23 Re: Energy balance #5 Julie Polyakh Guest   Posts: n/a Nice, but in my simulation Cp=Cp(T). Which Cp value should I take in such a case?

 July 5, 2004, 13:50 Re: Energy balance #6 Panos Guest   Posts: n/a You can use the formula Cp=a+bT+cT^2+dt^3 where the constants can be found in any book of physics and chemistry or thermodynamics. hope it is helpful

 July 5, 2004, 13:52 Re: Energy balance #7 4xF Guest   Posts: n/a You could try to write a macro for integrating between two surfaces mdot*Cp*T = H, where H is the enthalpy, T is the temperature, Cp is your local Cp(T) and m is the mass flux (mdot= rho*S*V, S is the surface, V is the velocity). Ask also your local support office, they MUST have a macro ready for that.

 July 6, 2004, 03:19 Re: Energy balance #8 Thomas Guest   Posts: n/a yes ans you can also use the operate command for this. you have 6 post registers to do this operation, thast should be enough!

 July 7, 2004, 03:58 Re: Energy balance #9 Julie Polyakh Guest   Posts: n/a Yes, Panos, I know. But there is also the chemical energy of unburned fuel that I have to take into account. Regards, Julie

 July 7, 2004, 04:00 OK. Thanks #10 Julie Polyakh Guest   Posts: n/a