In Example 1.2 we replaced a cylindrical problem with a linear approximation. The velocity distribution for this flow, taking the cylindrical character into account V₁ = ∞ (₁ ²²₂ ²) · ( ²² - , ) where R is the radius of the outer cylinder, r is the local radius, k = rinner cylinder / R, and @ is the angular velocity of the inner cylinder. (a) Verify that this distribution shows a zero velocity at the radius of the outer, non-moving cylinder and shows V₂ = kR at the surface of the inner, rotating cylinder. (b) The shear rate in cylindrical coordinates, for a fluid whose velocity depends only on r (equivalent to dV/ dy in rectangular coordinates), is given by 6= shear rate cylindrical coordinates rical) = r 2 " ( 1₁ ²= R²) 6 = w d dr Show that for the above velocity distribution, the shear rate at the surface of the inner cylinder is given by Ve (-;-) (c) Show that the shear rate is 12.26/s, which is 1.15 times the value for the flat approximation in Example 1.2. The

Introduction to Chemical Engineering Thermodynamics
8th Edition
ISBN:9781259696527
Author:J.M. Smith Termodinamica en ingenieria quimica, Hendrick C Van Ness, Michael Abbott, Mark Swihart
Publisher:J.M. Smith Termodinamica en ingenieria quimica, Hendrick C Van Ness, Michael Abbott, Mark Swihart
Chapter1: Introduction
Section: Chapter Questions
Problem 1.1P
icon
Related questions
Question

VO is a function of r.

Small r refers to the variable r, as in the radial direction in the cylindrical coordinates. Capital R refers to the radius of the outer cylinder and is a constant. Radius of the inner cylinder is defined as kR, where k (kappa) is also a constant.

In part (a), you are tasked to verify that the profile given in Eqn 1 is correct. You are evaluating the equation at two locations (outer cylinder, inner cylinder).

Recall that angular velocity is w (omega), and w # Ve. VO refers to the local linear velocity in the 0 direction (i.e., tangential velocity).

In part (b), you can ignore the resulting negative sign. You are looking for an expression of the magnitude of the shear rate o (sigma) at the inner cylinder. 

In Example 1.2 we replaced a cylindrical problem with a linear approximation. The
velocity distribution for this flow, taking the cylindrical character into account
V₁ = ∞ (₁ ²²₂ ²) · ( ²² - , )
1-k
where R is the radius of the outer cylinder, r is the local radius, k = Finner cylinder / R, and @
is the angular velocity of the inner cylinder.
(a) Verify that this distribution shows a zero velocity at the radius of the outer, non-moving
cylinder and shows V₂ = kR at the surface of the inner, rotating cylinder.
(b) The shear rate in cylindrical coordinates, for a fluid whose velocity depends only on r
(equivalent to dV/ dy in rectangular coordinates), is given by
6=
cal) = r
shear rate cylindrical
coordinates
0=w (₁²2
d
dr
Show that for the above velocity distribution, the shear rate at the surface of the inner
cylinder is given by
1-k²
Ve
(-;-)
(c) Show that the shear rate
is
12.26/s, which is 1.15 times the value for the flat approximation in Example 1.2. The
Transcribed Image Text:In Example 1.2 we replaced a cylindrical problem with a linear approximation. The velocity distribution for this flow, taking the cylindrical character into account V₁ = ∞ (₁ ²²₂ ²) · ( ²² - , ) 1-k where R is the radius of the outer cylinder, r is the local radius, k = Finner cylinder / R, and @ is the angular velocity of the inner cylinder. (a) Verify that this distribution shows a zero velocity at the radius of the outer, non-moving cylinder and shows V₂ = kR at the surface of the inner, rotating cylinder. (b) The shear rate in cylindrical coordinates, for a fluid whose velocity depends only on r (equivalent to dV/ dy in rectangular coordinates), is given by 6= cal) = r shear rate cylindrical coordinates 0=w (₁²2 d dr Show that for the above velocity distribution, the shear rate at the surface of the inner cylinder is given by 1-k² Ve (-;-) (c) Show that the shear rate is 12.26/s, which is 1.15 times the value for the flat approximation in Example 1.2. The
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 4 steps with 3 images

Blurred answer
Recommended textbooks for you
Introduction to Chemical Engineering Thermodynami…
Introduction to Chemical Engineering Thermodynami…
Chemical Engineering
ISBN:
9781259696527
Author:
J.M. Smith Termodinamica en ingenieria quimica, Hendrick C Van Ness, Michael Abbott, Mark Swihart
Publisher:
McGraw-Hill Education
Elementary Principles of Chemical Processes, Bind…
Elementary Principles of Chemical Processes, Bind…
Chemical Engineering
ISBN:
9781118431221
Author:
Richard M. Felder, Ronald W. Rousseau, Lisa G. Bullard
Publisher:
WILEY
Elements of Chemical Reaction Engineering (5th Ed…
Elements of Chemical Reaction Engineering (5th Ed…
Chemical Engineering
ISBN:
9780133887518
Author:
H. Scott Fogler
Publisher:
Prentice Hall
Process Dynamics and Control, 4e
Process Dynamics and Control, 4e
Chemical Engineering
ISBN:
9781119285915
Author:
Seborg
Publisher:
WILEY
Industrial Plastics: Theory and Applications
Industrial Plastics: Theory and Applications
Chemical Engineering
ISBN:
9781285061238
Author:
Lokensgard, Erik
Publisher:
Delmar Cengage Learning
Unit Operations of Chemical Engineering
Unit Operations of Chemical Engineering
Chemical Engineering
ISBN:
9780072848236
Author:
Warren McCabe, Julian C. Smith, Peter Harriott
Publisher:
McGraw-Hill Companies, The