Recent content by kaminho

would I be doing right if I found S2 and then multiply the \DeltaS by the mass flow rate? I meant after finding S2 of the irreversible process because S2 of isentropic is obviously same as S1.

Thank you. Can I ask, Just to make sure, in equation h[S]=hf+x2hfg after finding h2, will I be using the same values for hf and hfg which i used in the isentropic case? Any hints about rate of entropy generation during expansion please?

Any help please? Its the non-isentropic case with isentropic efficiency of 88% which I'm not sure about. I worked out the dryness fraction for case one (isentropic process) though.

Homework Statement I place the question first: Superheated steam at an absolute pressure of 10 bar and temperature of 340C expands in a nozzle reversibly and adiabatically until the pressure is 0.1 bar. the mass flow rate is 4.2kg/s. The questions asking for: 1) Drawing the appropriate...

Thank you rock.freak667 and nvn. I'm getting P=2.25 kN... cheers.

I get: I for shaft = (pi)(d^4)/64 = (pi) (0.05^4)/64 = 3.07 x 10^-7 m^4 \sigma= My/I = (4P x 0.2)(0.025) / (3.07 x 10^-7) = 65147P Pa (so this is my sigma x in last equation) for torsion equation: J= (pi)(d^4)/32 = 6.136 x 10^-7 m^4 (i used shaft's diameter i.e. 50 mm) T/J = \tau/r so...

I think i made an awful mistake in my previous post. As \tau is needed, it can not be the 150MPa in the question. Let me ask it this way. In equation: \frac{M}{I} = \frac{\sigma}{y} = \frac{E}{R} what are the unknowns? because i guess M (bending moment) is (4P)(0.2) and I (second moment of...

Thank you, I think one of the things I'm unsure about is whether that 150MPa (in the question) is bending stress or shear stress. assuming its shear, I used the equation: \frac{T}{J} = \frac{\tau}{r} = \frac{G \theta}{L} I first worked out J=\pid^4/32 = \pi0.05^4/32 = 6.136 x 10^-7 m^4 so...

Cheers, I think I know what I'm doing now. Thank you...

Yes i thought my formula is wrong as it assumes all he tower's mass to be at the very top. the answer to first part is right i know (ignoring tower's mass and having rotor+hub mass at the top end). i just used 48EI/L^3 and equated it to k. once i found k, finding natural frequency was straight...

so after i found r (frequency ratio) and subsequently Tr which is 0.2258 then the rest is pretty straight forward ? am i right in saying the magnitude of the harmonic force is always the applied force (Fo) and also the amplitude ? and thanks loads for the help too.

well at this stage I'm ignoring fatigue. i have to do it by finding the shear stress and bending stress and the mohr's circle eventually. but what i need is how can i find those two stresses using bending theory and torsion theory. I know for one that the torque in the pulley is (3p-p).(r) or...

Homework Statement An exhaust fan mass 90 kg operates at 1100 rpm and is supported by an UNDAMPED vibration isolator i.e a spring that has a stiffness of 220 kN. If the harmonic force produced by the fan has a magnitude of 12 kN determine: a) The transmitted force through the isolator to...

First of all, thank you well for the time being, I can ignore stresses of any kind. I know modulus of elasticity for the material. for case one (ignoring the tower's weight but taking into account mass of rotor and hub which I know of their values) I suppose I can make use of beam deflection...

how do we find the natural frequency of a tower of a wind turbine if, say, the tower is circular hollow cross sectional shape (its not tapered or anything, just cylindrical all the way up). I think i know how to find it when we're ignoring its weight, but what is it when weretaking into account...