KING FAHD UNIVERSITY CHEMICAL ENGINEERING COURSE NOTES (Process Control)-Lec12

KING FAHD UNIVERSITY CHEMICAL ENGINEERING COURSE NOTES (Process Control)-Lec12

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Chapter 4 ( 29 ( 29 ( 29 ( 29 ( 29 0 (8) i V C sT s T t wC T s T s Q s ρ ξ - = = - - ( 29 ( 29 ( 29 1 (10) 1 1 i K T s Q s T s s s τ @ = + + + ( 29 1 and 11 V K wC w @ @ G 1 and G 2 are transfer functions and independent of the inputs, Q′ and T i ′. Note G 1 (process) has gain K and time constant τ . G 2 (disturbance) has gain=1 and time constant τ . gain = G(s=0). Both are first order processes. If there is no change in inlet temperature (T i ′= 0), then T i ′(s) = 0. System can be forced by a change in either T i or Q (see Example 4.1). (s) T (s) G (s) Q (s) (s)=G T i + 2 1
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 Chapter 4 Transfer Function Between and Q V T V Suppose is constant at the steady-state value. Then, Then we can substitute into (10) and rearrange to get the desired TF: i T ( 29 ( 29 ( 29 0 0. i i i i T t T T t T s V = = = ( 29 ( 29 (12) 1 T s K Q s s τ = +
Background image of page 2
3 Chapter 4 Thus, rearranging ( 29 ( 29 1 (13) 1 i T s T s s τ = + Transfer Function Between and T V : i T V Suppose that Q is constant at its steady-state value: ( 29 ( 29 ( 29 0 0 Q t Q Q t Q s V = = =
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
4 Chapter 4 Answer : See (10). The same TFs are valid for simultaneous changes. Note that (10) shows that the effects of changes in both Q and are additive . This always occurs for linear, dynamic models (like TFs) because the Principle of Superposition is
Background image of page 4
Image of page 5
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 18

KING FAHD UNIVERSITY CHEMICAL ENGINEERING COURSE NOTES (Process Control)-Lec12

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online