PROBLEM 12.1
KNOWN: Rate at which radiation is intercepted by each of three surfaces (see (Example 12.1). FIND: Irradiation, G[W/m ], at each of the three surfaces. SCHEMATIC:
2
ANALYSIS: The irradiation at a surface is the rate at which radiation is inci
PROBLEM 5.1 KNOWN: Electrical heater attached to backside of plate while front surface is exposed to convection process (T,h); initially plate is at a uniform temperature of the ambient air and suddenly heater power is switched on providing a constant q .
135313 The base and the dome of a long semicyhndrical duct are maintained at uniform temperatures. The net rate of
radiation heat transfer from the dome to the base surface is to be determined.
Assumptions 1 Stead; operating oonditions exist 2 The surface
351 A thin copper plate is sandwiched between two epoxyI boards. The error involved in the total thermal resistance of the
plate ifthe thermal contact conductances are ignored is to be determined.
Assumptions 1 Steady operating conditions exist. 2 Heat tr
12-74 The variation of emissivity of a surface at a specied temperature with wavelength is given. The average emissivity of
the surface and its emissive power are to be determined.
Analysis The average emissivity of the surface can be determined 'om
a. 22
The Method of Scale Analysis
v.1.6
C. Thomas Avedisian
Cornell University
1.
Introduction
Scale analysis is a useful approach to provide valuable insights into transport processes governed
by a complex set of differential equations, yet without actually h
MAE 3240 Homework 2
Assigned on 2/11/2016. Due 2/23/2016 by 10 pm.
Please consult the course syllabus to ensure that your homework adheres to the required format.
2-34
2-86
3-29
Please also include in your answer the thermal conduction network for this
PROBLEM 11.1
KNOWN: Initial overall heat transfer coefficient of a fire-tube boiler. Fouling factors following one year's application. FIND: Whether cleaning should be scheduled. SCHEMATIC:
ASSUMPTIONS: (1) Negligible tube wall conduction resistance, (2)
PROBLEM 6.1 KNOWN: Variation of hx with x for laminar flow over a flat plate. FIND: Ratio of average coefficient, h x , to local coefficient, hx, at x. SCHEMATIC:
ANALYSIS: The average value of hx between 0 and x is hx = hx hx Hence, 1 x C x h x dx = x -1
PROBLEM 2.1
KNOWN: Steady-state, one-dimensional heat conduction through an axisymmetric shape. FIND: Sketch temperature distribution and explain shape of curve. SCHEMATIC:
ASSUMPTIONS: (1) Steady-state, one-dimensional conduction, (2) Constant properties
PROBLEM 1.41
KNOWN: Hot plate-type wafer thermal processing tool based upon heat transfer modes by conduction through gas within the gap and by radiation exchange across gap. FIND: (a) Radiative and conduction heat fluxes across gap for specified hot plat
PROBLEM 1.1 KNOWN: Heat rate, q, through one-dimensional wall of area A, thickness L, thermal
conductivity k and inner temperature, T1. FIND: The outer temperature of the wall, T2. SCHEMATIC:
ASSUMPTIONS: (1) One-dimensional conduction in the x-direction,
PROBLEM 4.1
KNOWN: Method of separation of variables for two-dimensional, steady-state conduction.
FIND: Show that negative or zero values of 2, the separation constant, result in solutions which
cannot satisfy the boundary conditions.
SCHEMATIC:
ASSUMPTI
1. Calculate the basis of the image 1 1 2 0 A= 1 0 2 1 and state its rank.
and kernal of the matrix 0 2 1 0 2 1 0 1 0 0 3 0
(a) Begin by either noticing the relations v1 + v2 = v4 , v3 = 0, (where vk is the kth column of A) or by reducing A to rref(A), at
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
PROBLEM 13.1
KNOWN: Various geometric shapes involving two areas A1 and A2. FIND: Shape factors, F12 and F21, for each configuration. ASSUMPTIONS: Surfaces are diffuse. ANALYSIS: The analysis is not to make use of tables or charts. The approach involves u