Hysis Question: mass flow dont change with Temperature

[smm1457]

Dear buddies!

I want to simulate a turbo-compressor (air compressor+turbine---->power)

it seems true! but i have a problem in sensitivity analysis : inlet Air Temperature

When i want to analysis inlet air temperature effect on Power, results are not correct.

i think it is due to constant inlet mass flow of compressor. as you know, in practice, mass will change!

because phro will change!

can any one help me?

thanks in advance!

[yogi_process]

The gas machines are designed for Standard/Actual Volumetric flow rates so check your volumetric flow rates as that is the way your machine will operate....dont think of mass flow for rotating machines with gas./vapor.

[smm1457]

thank u so much dear yogi_process

you right, but i want to consider off design conditions.

turbo-compressors designed in ISO condition, but work on different conditions.



as u know, by decreasing inlet air T, net obtained power will be increased.

my results are good in "design condition": stack T, net Power, compressor load and so on

but i can not investigate off design conditions.

by the way, Standard/Actual Volumetric flow means specific mass flow @ design condition, Ok?

now, if T decreases, mass flow increased and we can obtain more work (Mdot*deltaP) from the same flow. isn't it?

if i'm wrong, please tell me how can i reproduce this figure?

[link Point to another website Only the registered members can access]
Figure 20-15. Correction factor for power as a function of inlet ambient air
temperature.
Gas turbine engineering handbook / Meherwan P. Boyce. – 3rd ed, p 750.


as i said, as i said, i think it is due to mass conservation in the material stream that is entered to the air compressor. (when T increases, mass density will be decreased and actual flow will be increased thus mass flow will conserved and vice verse)

P.M:
when i adjust fuel consumption (mass flow) to the mass density of inlet air, results seem good! but this is not a straight forward method!

[hainambkhn]

this is the firt time I attend forum. I know, Hysys is very importance in chemical's student. And I hope I can learn from you so much. thanks

[dipsi30]

Hi,
Mass flow rate won't change with pressure & temperature. Volumetric flow rate changes with change in pressure & temperature due to change in density with pressure & temperature.