Efficiency is more means the temperature variation is less and vice versa. If the length of the fin is more its efficiency is poor, but its
effectiveness will be high
. Both Fin Effectiveness and Fin Efficiency are related to heat transfer from the Fin.
What is fin and effectiveness of fin?
Effectiveness of fin (εfin):
It is defined as
the ratio of the actual heat transfer that takes place from the fin to the heat that would be dissipated from the same surface area without fin
.
What is the fin effectiveness?
The fin temperature effectiveness or fin efficiency is defined as
the ratio of the actual heat transfer rate through the fin base divided by the maximum possible heat transfer rate through the fin base
, which can be obtained if the entire fin is at base temperature (i.e., its material thermal conductivity is infinite).
What is the importance of fin effectiveness?
Fin effectiveness is
the ratio of the rate of heat transfer by use of fin to the rate of heat transfer without fin
. The value of effectiveness indicates the increase in the rate of convective heat transfer from the body after the addition of fins, therefore the value of effectiveness should be greater than 1.
Does the i efficiency and II effectiveness of a fin increase or decrease as the fin length is increased explain?
Increasing the length of a
fin decreases its efficiency but increases its effectiveness
. Chapter 3, Solution 107C. Increasing the diameter of a fin increases its efficiency but decreases its effectiveness.
What is fin efficiency Mcq?
ANSWER: a.
the ratio of actual heat transferred from fin area to the heat which would be transferred if entire fin area was at base temperature
.
Which is true about effectiveness of fin?
Fin effectiveness is
the ratio of actual heat transfer that takes place from the fin to the heat that would be dissipated from the same surface area without fin
i.e. From equation obtained of the effectiveness it can be found that, effectiveness increases with increase in thermal conductivity and circumference.
What is fin performance?
Fin performance can also be characterized by fin efficiency. This is the
ratio of the fin heat transfer rate to the heat transfer rate of the fin
if the entire fin were at the base temperature, in this equation is equal to the surface area of the fin.
How do you calculate fin efficiency?
- The fin efficiency is defined as the ratio of the heat transfer to the fin to the heat transfer to an ideal fin. ηth =
- qfin. hAfin(Tb − T∞) , Tf = T∞,and Afin = 2Ac + Atip (Square and Recatngular ) 1.35.
- Atip = t × W. Fig. 2.4. Rectangular Fin. For cylindrical: Afin = πDL +
What is meant by effectiveness in heat exchanger?
The effectiveness (ε) of a heat exchanger is defined as
the ratio of the actual heat transfer to the maximum possible heat transfer
.
In which case the efficiency of the fin will be maximum Mcq?
The effectiveness of a fin will be maximum in an environment with.
Free convection
.
Which type of design of fins is more effective?
The rectangular fin with single-step change
has been found to be the most efficient fin profile in terms of maximum heat loss and fin efficiency.
In which case the efficiency of the fin will be maximum?
The effectiveness of a fin will be maximum in
an environment with free convection
. Explanation: The fin temperature is also known as the fin effectiveness. Thus it is defined as the ratio of the actual amount of the heat transfered to the to the divided base temperature in the serve.
Can fin efficiency be greater than 1?
3. An effectiveness of εf >1 indicates that the fins are enhancing heat transfer rate from the surface to the surrounding. However, the role of
a fin cannot be justified unless η is sufficiently larger than 1
.
What is effectiveness of fin Examveda?
Fin efficiency is defined as the
ratio of heat transferred across the fin surface to the theoretical heat
transfer across an equal area held at the. A. Surrounding temperature. Average temperature of the fin.
What makes a good fin heat transfer?
Typically, the fin material has
a high thermal conductivity
. The fin is exposed to a flowing fluid, which cools or heats it, with the high thermal conductivity allowing increased heat being conducted from the wall through the fin.
What is effect of thermal conductivity on fin effectiveness?
Results show that the PCHE fin effectiveness is enhanced by the choices of high fin thermal conductivity,
decreasing the ratio of the fin thickness to the radius of the channels
, or under conditions for which the convective coefficient is small.
What is the function of fin?
Fins typically function as foils that produce lift or thrust, or
provide the ability to steer or stabilize motion while traveling in water, air, or other fluids
. Fins are also used to increase surface areas for heat transfer purposes, or simply as ornamentation. Fins first evolved on fish as a means of locomotion.
What is the meaning of fin is insulated at the tip?
“Fin is insulated at the tip”. … Explanation: The
fin is of finite length with the tip insulated and so no heat is transferred from the tip.
Why are fins used?
Fins are thus used
whenever the available surface area is found insufficient to transfer required quantity of heat with available temperature gradient and heat transfer coefficient
. In the case of fins the direction of heat transfer by convection is perpendicular to the direction of conduction heat flow.
What are the types of fins?
For each fish, generally, there are five main fins follows:
Dorsal, Pelvic, Caudal (tail), Anal and Pectoral
as shown in Fig. 1. Dorsal fins are located either on the back of the fish or its top, it helps the fish during sharp turning or stops.
What is the effectiveness a function of in all heat exchangers?
The heat exchanger effectiveness is defined as
the ratio of actual heat transfer to the maximum possible heat transfer
. NTU is a measure of the effectiveness of the heat exchanger.
How do you calculate the effectiveness of a heat exchangers?
If one of the fluids is undergoing a change of phase throughout the entire heat exchanger and at a constant temperature (i.e. heat capacity is infinite), the thermal efficiency is simply
Eff=1-exp(-U.A/Cmin)
, where Cmin is the heat capacity (m x cp) for the single phase fluid, U-overall heat transfer coeffcient and A …
How does heat exchanger compare to efficiency?
Heat exchanger effectiveness
You can compare the current heat transfer rate to the original (rated) heat transfer rate.
A ratio of (Q/rated duty)
will tell you how effectively your exchanger is working.
What is corrected fin length?
Corrected fin length Lc is defined such that heat transfer from a fin of length Lc with insulated tip
is equal to heat transfer from the actual fin of length L with convection at the fin tip
.
What is the effect of convective heat transfer coefficient Hon fin effectiveness?
The higher value of h
causes the smaller efficiency and effectivity
of the fin. … Thus, the greater the value of the convective heat transfer coefficient the smaller fin’s efficiency as also happens with the fin’s effectivity.
Which type of condensation is better *?
Dropwise condensation
is one of the most effective mechanism of heat transfer and extremely large heat transfer coefficients can be achieved with this mechanism.
What is the critical thickness of insulation?
Critical thickness of insulation means
maximum heat loss with min thermal resistance
. This concept is useful in the situation when surface area of the base object increases with the insulation, i.e., cylindrical and spherical systems.
Why are fins used in Mcq?
Explanation: Fins are the projections protruding from the hot surface into the ambient fluid and they are meant
for increasing the heat transfer by increasing the heat transfer area
.
Which one of the following configuration has the highest fin effectiveness Mcq?
Which one of the following configurations has the highest fin effectiveness ? Fin effectiveness is defined as the ratio of the fin heat transfer rate to the heat transfer rate that would exist without the fin. And it is highest with
Thin and closely spaced fins
.
