Calculating (Seiliger) Cyclic Process - beginner question
Calculating (Seiliger) Cyclic Process - beginner question
(OP)
Hi to all,
I am new here and hope that you would help me figure out a few things, that don't let me sleep lately :(
first one:
I'm given a Seiliger CP (Engine). Given is:
T1 = 300K
p1 = 2,25 bar
E = V1/V2 = 17
V(h) = V1-V2 = 0,003 m^3
R = Rair = 287,1 Nm/Kg*K (for the whole problem)
etc.
(* some of the letters might not be those you are used to see (like Vh for sure) as the data is given in German, sorry. I think Vh is translated Cubic Capacity in English, not sure...)
What I first did is I calculated V1 using the ideal gas low:
p*V1 = R*T1 ===> V1 = 0,3828 m^3
as V2 = V1/E = 0,0225 m^3
obviously something here is wrong, as Vh which is V1-V2 is no longer = 0,003m^3
I can also go ahead and use E and Vh and calculate as follows:
E = V1/V2 = 17 ==> V1 = 17*V2
Vh = V1 - V2 = 17*V2 - V2 = 0,003 m^3
==> V2 = 0,0001875 m^3 and V1 = 17*V2 = 0,0031875
This also looks more right, but why is the Ideal Gas low no longer valid here?? For the other steps (2,3,4,5) it is used again to find various unknows parameters...
I'm confused!?
Thank you in advance guys!!!
I am new here and hope that you would help me figure out a few things, that don't let me sleep lately :(
first one:
I'm given a Seiliger CP (Engine). Given is:
T1 = 300K
p1 = 2,25 bar
E = V1/V2 = 17
V(h) = V1-V2 = 0,003 m^3
R = Rair = 287,1 Nm/Kg*K (for the whole problem)
etc.
(* some of the letters might not be those you are used to see (like Vh for sure) as the data is given in German, sorry. I think Vh is translated Cubic Capacity in English, not sure...)
What I first did is I calculated V1 using the ideal gas low:
p*V1 = R*T1 ===> V1 = 0,3828 m^3
as V2 = V1/E = 0,0225 m^3
obviously something here is wrong, as Vh which is V1-V2 is no longer = 0,003m^3
I can also go ahead and use E and Vh and calculate as follows:
E = V1/V2 = 17 ==> V1 = 17*V2
Vh = V1 - V2 = 17*V2 - V2 = 0,003 m^3
==> V2 = 0,0001875 m^3 and V1 = 17*V2 = 0,0031875
This also looks more right, but why is the Ideal Gas low no longer valid here?? For the other steps (2,3,4,5) it is used again to find various unknows parameters...
I'm confused!?
Thank you in advance guys!!!





RE: Calculating (Seiliger) Cyclic Process - beginner question
ideal gas law not pv=mrt?
E=compression ratio
V(h)=swept volume
RE: Calculating (Seiliger) Cyclic Process - beginner question
Check your units on p*V1 = R*T1. V1 should be volume/moles.
Good luck,
Latexman
RE: Calculating (Seiliger) Cyclic Process - beginner question
and R is R specific (Nm/Kg*K) - that's why no m or n.
RE: Calculating (Seiliger) Cyclic Process - beginner question
Good luck,
Latexman
RE: Calculating (Seiliger) Cyclic Process - beginner question
P V = m R T
N * m-2 * m3 = mol * Nm * K-1 * mol-1 * K
Nm=Nm
or
R=Nm * K-1 * kg-1
P V = m R T
N * m-2 * m3 = kg * Nm * K-1 * kg-1 * K
Nm=Nm
you left out the amount of gas (mol or kg)
RE: Calculating (Seiliger) Cyclic Process - beginner question
I am also trying to calcucalte the efficiency of the turbo compressor attached to the engine....
As far as I remember this should be possible based on the input and output temp and pressure...
I have:
Tin (atmospheric) - 273,15K
Pin (atmospheric) - 1 bar
Tout - 360K
Pout - 2,25 bar
Could anyone please remind me how this is calculated... the expected result should be about 0,82 ...
RE: Calculating (Seiliger) Cyclic Process - beginner question
RE: Calculating (Seiliger) Cyclic Process - beginner question