Recent content by albertov123

I stumbled upon this concept when studying gas dynamics. What I get from my readings it must occur when Mach number is really close to 1. But I didn't understand how the property relations across a shock wave is affected by it.

Homework Statement A rigid and evacuated container of volume V that is surrounded by atmosphere (P0, T0). At some point neck valve opens and atmospheric air gradually fills the container. The wall of container is thin enough so that eventually the trapped air and atm reach thermal equilibrium...

It's a bit complicated.

Could turbine exhaust temperature be negative celsius? My calculations yield 176 K. Is that possible? Inlet conditions are 7.8 MPa and 625 K. Exit pressure is 1 atm. (100 kPa.)

Oh, I see. That helped a lot. Thank you so much.

From q - w = ΔH = cp (T3-T2) I get q = 32 kJ/kg sgen = Δs - q/T = 0,052 - 32 kJ / 600 K = 0.052 - 0.053 = - 0.01 Edit: Why didn't you involve work in your first law equation? Isn't there some boundary work PdV also. That is why I get q = w + cp(500-475) = 7 + 25 = 32 kJ/kg

For the reversible adiabatic compression part. (Between 1-2) v1 = 0.861 m3/kgFrom T2/T1 = (P2/P1)(k-1)/k T2 = 475.15 K- W = U = cv (T2-T1) W = - 126 kJReversible adiabatic means isentropic. Sgen = 0 For the internally reversible isobaric heating (Between 2-3) W = PdV = 500 kPa ...

Homework Statement Air at 100 kPa, 300 K is to be delivered to a pipeline at 500 kPa, 500 K. The scheme involves reversible adiabatic compression of the air and then internally reversible isobaric heating. Assume that, heat is exchanged with a reservoir at 600 K. Determine the work and...

Actually, this was the lecturer's example which confused me on the subject. Before that, I was confident about the work done by gas and irreversibility concepts. A rigid and evacuated container's valve is opened and atmospheric air filled it and became in equilibrium with the outside(thermally...

I am trying to grasp the concepts of reversible work, irreversible work and irreversibility.(Last one is the difference between them if i am not mistaken.) Let us consider a rigid and evacuated container at volume V. Then, a valve opens and athmospheric air (P0, T0 is filling the tank. The wall...

Oh, you are saying that a rotational motion could be considered in an inertial ref. frame. Then, let me dive into my source of confusion. We are learning reference frames and when I see a rectilinear acceleration, I understand there is a non-inertial reference frame also accelerating with the...

When rotation exists, so does the radial acceleration. It can be defined as ar=-ω2xr So there is a kind of acceleration with rotation all the time. Thus, we have to use non-inertial reference frame all the time. Could a rotational movement be analysed in an inertial ref. frame?

Yes we are learning maxwell equations in fact. That derivation must be dG=-SdT+VdP+∑μidNi from my notebook. The relation you have mentioned is probably -(∂S/∂P)T=(∂V/∂T)P and with that equation my solution would include state 3. But how could i go with this equation I'm not clear. Although I'm...

Homework Statement Temperature, pressure and volume measurements performed on 1 kg of a simple compressible substance in three stable equilibrium states yield the following results. State 1 (T1=400 C , V1= 0,10 m3, P1=3 MPa) State 2 (T1=400 C , V1= 0,08 m3, P1=3,5 MPa) State 3 (T1=500 C , V1=...

When I was designing a Kaplan (hydraulic) turbine, I chose a couple of airfoil profiles which are extensively used in turbine blade design, i created 3D models of them and made CFD analyses for each, in order to understand which one would yield the maximum torque at given conditions. You...