PROBLEM 14.1
KNOWN: Mixture of O2 and N2 with partial pressures in the ratio 0.21 to 0.79. FIND: Mass fraction of each species in the mixture. SCHEMATIC:
pO2 p N2
MO M
=
0.21 0.79
2
= 32 kg/kmol
N2 = 28 kg/kmol
ASSUMPTIONS: (1) Perfect gas behavior. ANALY
ME 315
Exam 2
8:00 -9:00 PM
Tuesday, March 10, 2009
This is a closed-book, closed-notes examination. There is a formula sheet at the
back.
You must turn off all communications devices before starting this exam, and
leave them off for the entire exam.
P
ME 315
Final Exam
Friday, May 3, 2013
This is a closed-book, closed-notes examination. There is a formula sheet
provided at the end of this exam.
You must turn off all communications devices before starting this exam, and
leave them off for the entire e
Name:
Problem 1 (20 points)
Consider a micron sized spherical coal particle moving inside a combustor of approximately 5 m in
length as shown in the figure below. (The drawing is not to scale. The reactor walls extend on both
sides in the vertical directi
BASIC EQUATION SHEET
Conservation Laws
.
.
.
.
.
.
.
Control Volume Energy Balance: Ein Eout + Egen = Est ; Est = mC p dT ; Egen = q V
dt
.
.
Surface Energy Balance: Ein Eout = 0
Conduction
"
"
"
Fouriers Law: qcond , x = k T ; qcond ,n = k T ; qcond = qc
1. [35 points] In materials processing, a metal plate with an initial temperature T,- = 800 K is
taken out of furnace and cooled down. The thickness of the plate is 2L where L = 0.25m,
and the height and width of the plate are much larger than the thickne
ME 315 Exam 1
BASIC EQUATION SHEET
Conservation Laws
Control Volume Energy Balance: Ein Eout + Egen = Est ; Est = mC p dT
Surface Energy Balance: Ein Eout = 0
dt
; Egen = qV
Conduction
"
"
"
Fouriers Law: qcond , x = k T ; qcond ,n = k T ; qcond = qcond A
Pz'cblem 11(20 points)
(a) (10 points) Two verticai plates with di'erem surface temperature are in the gure
below. Draw a qmtative' sketch of the boundaxy layers that are formed along the two plates.
Indicate the co-ardinate system fox both the pIates.
BASIC EQUATION SHEET
Conservation Laws
.
.
.
.
.
Control Volume Energy Balance: Ein Eout + Egen = Est ; Est = mc p dT ; Egen = qV
dt
.
.
Surface Energy Balance: Ein Eout = 0
Conduction
"
"
"
Fouriers Law: qcond , x = k T ; qcond ,n = k T ; qcond = qcond A
ME315 F2016 Quiz # 2
Number:
Name:
Signature:
Rank their thermal conductivity from high to low: (near room temperature, 1 being the highest)
(
(
2 ) Silver
1 ) Diamond
( 3 ) Glass
( 6 ) Air
(4 or 5) Foams
(5 or 4) Oil and Water
True or false:
( F ) Therma
ME315 F2016 Quiz # 3
Number:
Name:
Signature:
True or false:
When we solve a heat diffusion equation,
(T) Boundary conditions are always needed to solve a heat diffusion equation
(F) Initial condition is always needed to solve a heat diffusion equation
(F
ME315 F2016 Quiz # 1
Number:
Name:
Signature:
True or false:
( F ) Heat diffuses along the direction of the temperature increases
( F ) A higher temperature object contains more thermal energy than the lower temperature ones
( F ) Heat cannot be generated
ME315 F2015 Quiz # 1 08/28/2015
Number:
Name:
Signature:
True or false:
( F ) Heat diffuses along the direction of the temperature increases
( F ) A higher temperature object contains more thermal energy than the lower temperature ones
( F ) Heat cannot b
ME315 F2015 Quiz # 5 09/25/2015
Number:
Name:
Signature:
True or false:
When we solve a steady-state fin heat transfer problem:
(T) The 1D fin heat transfer equation does NOT give the EXACT solution.
(T) The infinitely long fins have zero fin efficiency.
ME315 F2015 Quiz # 3 09/09/2015
Number:
Name:
Signature:
True or false:
When we solve a heat diffusion equation,
(T) Boundary conditions are always needed to solve a heat diffusion equation
(F) Initial condition is always needed to solve a heat diffusion
ME315 F2015 Quiz # 7 10/22/2015
Number:
Name:
Signature:
Draw the Curves
For the isothermal flat plate being heated by a freestream (i.e., Ts < T), sketch the thermal boundary
layer thickness as a function of x from 0 to L, and carefully draw the temperat
ME315 F2015 Quiz # 9 11/04/2015
Number:
Name:
Signature:
Consider an internal flow through a pipe:
The entrance length is short and we can assume the flow is hydrodynamically and thermally fully developed
everywhere. As shown in the graph below, the fluid
ME315 F2015 Quiz # 2 09/02/2015
Number:
Name:
Signature:
Rank their thermal conductivity from high to low: (near room temperature, 1 being the highest)
( 2 ) Silver
(4 or 5) Foams
( 6 ) Air
( 3 ) Glass
( 1 ) Diamond
(5 or 4) Oil and Water
True or false:
(
ME315 F2015 Quiz # 4 09/16/2015
Number:
Name:
Signature:
Draw the circuit: Draw an effective circuit of the composite wall below (no need to label T, Rt and qx).
B
T 1
A
D
T 2
C
True or false: Consider applying a thermal insulation layer around a hot meta
ME315 F2016 Quiz # 6
Number:
Name:
Signature:
Make your Choices
Decide the validity of lumped capacitance analysis for the following cases: (Y, N or N/A)
(N) Biot number is 1
(Y) Biot number is 0.01
(N/A) The material is metal with high thermal conductivi
ME 315 - EXAM 1
EXAMPLE EQUATION SHEET*
*Hard copy of a very similar equation sheet will be provided during the exam.
Conservation Laws
Control Volume Energy Balance:
;
;
Ein Eout Egen Est E mC dT
st
p
Surface Energy Balance:
Conduction
Fouriers Law:
"
co
ME315 F2016 Quiz # 5
Number:
Name:
Signature:
1. Consider a fin with a uniform cross section and an adiabatic tip, subject to a constant base temperature,
which is higher than the ambient temperature. As the length of the fin increases,
Circle the correct
PURDUE UNIVERSITY
School of Mechanical Engineering
ME 315
HEAT AND MASS TRANSFER
Fall 2016
Lecture:
Division 1: MWF 8:30am-9:20am, Rm ME 2061
Professor Sameer Naik (Rm ME G092, Tel. 49-62183, email: naiks)
Office Hours: MWF 12:30pm-1:30pm, ME G092
Divisio
Prof.Naik 2016
ME 315: Heat and Mass Transfer
Lectures 1-2: Introduction, Rate Equations,
Conservation of Energy
Prof.Naik 2016
This Lecture
Course Organization
Modes of Heat Transfer
Conduction
Convection
Radiation
Conservation of Energy
Prof.Naik 201
Prof.Naik 2016
ME 315: Heat and Mass Transfer
Lecture 5: Steady State Conduction (b)
Prof.Naik 2016
Last Lecture
Generalized heat diffusion equation is second-order in
space and first-order in time; need two boundary conditions
for each dimension and init
Prof.Naik 2016
ME 315: Heat and Mass Transfer
Lectures 3-4: Steady State Conduction (a)
Prof.Naik 2016
Last Lecture
Conduction due to random microscopic motion
q
conduction
Convection due to bulk motion of fluid (liquid/gas) relative to
a solid surface
q
Prof.Naik 2016
ME 315: Heat and Mass Transfer
Lecture 6: Steady State Conduction (c)
Prof.Naik 2016
Last Lecture
Steady state conduction through planar systems
Concept of thermal resistance and thermal circuits; its
equivalence to electrical resistance an