hw9 - CE 561 Homework 9: Assigned 11/02/09, due 11/09/09...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Assigned 11/02/09, due 11/09/09 (1) In class, we derived a set of partial differential equations that, with some assumptions, govern the spatial and temporal behavior of species concentrations in a chemically reacting system. dC dt v C D C r k k k k ik i i M = − ⋅∇ + + = 2 1 α , for k from 1 to N , the number of species. If the reactor to be modeled has turbulent flow or has complex flow patterns through a bed of catalyst, then the diffusion coefficients, D k are not molecular diffusion coefficients. Instead, they are effective diffusion coefficients that are related to mixing in turbulent eddies and in complex flow patterns past catalyst particles. In that case, the diffusion coefficients are the same for all of the species. We can define extents of reaction such that the species concentrations are related to the extents of reaction by C C k k o ik i i M = + = , αξ 1 where the C k,o are some reference concentrations (usually the feed concentrations) and the ξ i are the extents of reaction (with units of concentration). Starting from the above PDE’s for the concentrations (with the same effective diffusion coefficient for all species) and this definition of the extents of reaction, derive a set of M equations in terms of the extents of reaction that are equivalent to the N equations in terms of the concentrations. (2)
Background image of page 1

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

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This document was uploaded on 07/08/2011.

Page1 / 3

hw9 - CE 561 Homework 9: Assigned 11/02/09, due 11/09/09...

This preview shows document pages 1 - 2. Sign up to view the full document.

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