10.2 Heat Transfer Phenomena are Described
by Governing Equations
Many engineering problems are treated as applied science or applied physics
problems. Heat transfer problems are no exception, and are based on general laws
and particular laws (see below for their definitions). A brief outline of which is
given in this section. The purpose of this outline is for identifying an unexamined
doctrine of applied science problems, the doctrine of determinism. Thereupon, in
the next two sections, Sects. 10.3 and 10.4, a characterization of problems
involving shaft work will be made by rejecting the doctrine to inform engineering
students of the defining nature of engineering thermodynamics that demarcates it
from typical applied sciences.
As presented by Yener and Kakac, [2] the theoretical foundations of heat transfer
are general laws:
1. The law of conservation of mass,
2. Newton’s second law of motion,
3. The first law of thermodynamics, and
4. The second law of thermodynamics (it should be stricken out for reason given
below)
In addition to these general laws, certain particular law, which are dependent on
the nature of the medium under consideration while general laws are applicable to
all media independent of their nature have to be brought into the application of
general laws. They are
1. Fourier’s law of heat conduction,
2. Newton’s law of cooling, and
3. The Stefan-Boltzmann law of radiation.
It should first be pointed out that the customary inclusion of the second law of
thermodynamics serves no concrete purpose as the general law is not required
independently as every particular law is necessarily consistent with the second law,
and thus their inclusion in the first law of thermodynamics guarantees universal
entropy growth. Thus, for phenomena considered in this section, the above #4 is
merely a distraction. Another immediate comment is that Newton’s law of cooling
is used for one kind of boundary condition for heat conduction problems as an
empirical input but otherwise unnecessary if the heat transfer problems are investigated based on first principles (of general laws and two particular laws of heat
conduction and heat radiation).
Let us consider the first law of thermodynamics beginning with Eq. (23A),
dE ¼ dQ À dW;
which applies to a closed system, we may write it as a rate equation
10.2 Heat Transfer Phenomena are Described by Governing Equations
277
by Governing Equations
Many engineering problems are treated as applied science or applied physics
problems. Heat transfer problems are no exception, and are based on general laws
and particular laws (see below for their definitions). A brief outline of which is
given in this section. The purpose of this outline is for identifying an unexamined
doctrine of applied science problems, the doctrine of determinism. Thereupon, in
the next two sections, Sects. 10.3 and 10.4, a characterization of problems
involving shaft work will be made by rejecting the doctrine to inform engineering
students of the defining nature of engineering thermodynamics that demarcates it
from typical applied sciences.
As presented by Yener and Kakac, [2] the theoretical foundations of heat transfer
are general laws:
1. The law of conservation of mass,
2. Newton’s second law of motion,
3. The first law of thermodynamics, and
4. The second law of thermodynamics (it should be stricken out for reason given
below)
In addition to these general laws, certain particular law, which are dependent on
the nature of the medium under consideration while general laws are applicable to
all media independent of their nature have to be brought into the application of
general laws. They are
1. Fourier’s law of heat conduction,
2. Newton’s law of cooling, and
3. The Stefan-Boltzmann law of radiation.
It should first be pointed out that the customary inclusion of the second law of
thermodynamics serves no concrete purpose as the general law is not required
independently as every particular law is necessarily consistent with the second law,
and thus their inclusion in the first law of thermodynamics guarantees universal
entropy growth. Thus, for phenomena considered in this section, the above #4 is
merely a distraction. Another immediate comment is that Newton’s law of cooling
is used for one kind of boundary condition for heat conduction problems as an
empirical input but otherwise unnecessary if the heat transfer problems are investigated based on first principles (of general laws and two particular laws of heat
conduction and heat radiation).
Let us consider the first law of thermodynamics beginning with Eq. (23A),
dE ¼ dQ À dW;
which applies to a closed system, we may write it as a rate equation
10.2 Heat Transfer Phenomena are Described by Governing Equations
277