The use of fins is most effective in applications involving
low convection heat transfer coefficient
. Thus, the use of fins is more easily justified when the medium is a gas instead of a liquid and the heat transfer is by natural convection instead of by forced convection.
How do you increase fin effectiveness?
- P.Kh.Ac should be greater than unity if the rate of heat transfer from the primary surface is to be improved.
- If the ratio of P and Ac is increased , the effectiveness of fin is improved.
- Use of fin will be more effective with materials of large thermal conductivities.
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.
Which one of the following is correct the effectiveness of a fin will be maximum in an environment with?
The effectiveness of a fin will be maximum in an environment with.
Free convection
.
What is 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).
Can fin effectiveness be less than 1?
The fin efficiency will always be less than one
, as assuming the temperature throughout the fin is at the base temperature would increase the heat transfer rate. … This is the efficiency for an array of fins.
How can you increase the efficiency and effectiveness of a fin?
- P.Kh.Ac should be greater than unity if the rate of heat transfer from the primary surface is to be improved.
- If the ratio of P and Ac is increased , the effectiveness of fin is improved.
- Use of fin will be more effective with materials of large thermal conductivities.
Which material is ideal for making a fin?
Aluminium
is one of the most frequently used materials for fin due to its higher thermal conductivity and comparatively low cost. Triangular shape is best from point of view of heat transfer to weight ratio. Length of fin would depend upon the rate of heat transfer.
Which fin is best for heat transfer?
Staggered arrangement produces higher heat transfer and friction factor than inline fin. Moreover,
the rectangular fin
is the best in terms of high heat transfer however the drawback of high friction factor leads the fin to have the least efficiency of all.
Why fin is insulated at tip?
“Fin is insulated at the tip”. What does that mean? Explanation:
The fin is of finite length with the tip insulated and so no heat is transferred from the tip.
Under what condition does fin efficiency reach 100%?
Under what situations does the fin efficiency becomes 100%.
The heat transfer from the fin will be maximum. For the
cases of a constant cross-section of very long fins and fins with insulated tips
, the fin efficiency can be 100.
What is the effect of thermal conductivity on fin effectiveness?
10a-d shows that the fin efficiency
decreases monotonically
(for different thermal conductivity and at a constant heat transfer coefficient) with increasing thermogeo- metric parameter. Also, it shows the variation of fin efficiency with thermogeometric in longitudinal convecting fin with insu- lated tip.
Which has high thermal conductivity?
| Common metals ranked by thermal conductivity | Rank Metal Thermal Conductivity [BTU/(hr·ft⋅°F)] | 1 Copper 223 | 2 Aluminum 118 | 3 Brass 64 |
|---|
What is an ideal fin?
An ideal fin is
the one whose temperature is equal to temperature of the surface
. This is possible only if the thermal conductivity of fin material is infinitely high. The effectiveness of an actual fin material is always lower than an ideal fin.
What is difference between fin efficiency and fin effectiveness?
Therefore, the fin effectiveness can be
determined easily when
the fin efficiency is known, or vice versa. The thermal conductivity k of the fin material should be as high as possible. The overall effectiveness is a better measure of the performance of a finned surface than the effectiveness of the individual fins.
Which one of the following configurations has the highest fin effectiveness?
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
. According to the reciprocity relation.
