Unformatted text preview: Student Name:______________________________________ HW #3 CHE 461 Due Mon Apr. 19, 2010 Read Chapter 11 in SEM2
pgs 260282 = review of block diagrams and feedback fundamentals in more complex situations
pgs 283286 =Routh Stability Criterion and Direct Substitution Method = RS and DS methods
Problems to solve from SEM2 textbook ....
1.(10) SEM2  Ex9.4 pg. 229: Use R = 40 in the f(l) equation for the equal percentage control
valve, i.e. the same value of R shown in Fig. 9.8 pg. 217 SEM2.
NOTE: The specification in the problem requires you to use f(l) = 0.5.
This is because the valve is set at half it's maximum flow characteristic ( f ), NOT set at
half open = lift ( l ) when you are operating at the nominal flow rate.
There is a different value of constant total pressure drop you must use for each nominal
design case.
You need to use three different Cv (different size of valves, round to nearest 0.1) for the
three cases of pressure drop across the valve: a,b,c = 5, 30, 90 psi respectively.
For parts a,b and c you must use MATLAB to “Make plots of flow rate versus valve
stem position ...” with appropriate labels and titles that include: your name,
“CHE461S10” and the date you made the plot. Don’t forget to include in your HW
solution the required comments on linearity of the installed valve in each case.
2.(6) Ex11.4 all parts ac, pg. 290 – See Fig E11.4
For part (b), derive numerical transfer functions for all 7 blocks to be used in a similar
configuration to Fig. 11.16, except that here the Gd and Gp transfer functions are not the
same (you get those two from a material balance linearization). Assume Gm (info. # 5) is
time delay without poles or zero. Use the dimensions given in the problem for your
transfer function inputs and outputs, e.g. gal/min for flow rates and lb/ft3 for mass
concentrations. 3.(4) Ex11.19 pg. 296 In part (b) the right half plane zero is “eliminated” when the factor
(15s) is simply replaced by (1) in the numerator of G(s). Don’t forget to answer part (c). ...
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This note was uploaded on 04/17/2010 for the course CHE 213 taught by Professor Staff during the Winter '08 term at Oregon State.
 Winter '08
 Staff

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