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R. V. Unni and M. Sreedhar Babu
under natural convection, the use of geometry which results in optimum cooling rate
becomes significant. Therefore, the geometry of HS promoting optimum cooling
with least material is an area to explore. Thus, the design of HS is considered as an
important subject to pursue and contribute. Besides this, materials used for fins should
possess good thermal conductivity to facilitate better heat transfer. Materials, such as
aluminum, copper, silver, are known for their higher thermal conductivity. However,
among these aluminum is cost-effective. In the following sections, discussions related
to experimental method and the outcome of experiments are presented.
2 Literature Review
Starner et al. [1] performed experimental studies on rectangular fin arrays and
compared the results with Elenbass [2]. Retaining the fin length (10 in.), fin width
(5 in.) and fin height (0.04 in.) constant, he varied fin spacing (0.25–0.313 in.) and
number of fins (15 and 17). For different inclinations, flow patterns were studied and
observed that the use of optimum number of fins increases the rate of heat dissipation. It was also observed that, for small spacing, due to interference in the boundary
layer, i.e., airflow obstruction, convection coefficient values were less as compared
to wider values of spacing. Average heat-transfer coefficient values [3] for shorter
fin (5 in.) length were higher as compared to longer (10 in.) fin length.
Leung et al. [4] carried out experimental work considering three cases, namely
vertical fins with horizontal base, vertical fins with vertical base and horizontal fins
with vertical base. For constant temperature difference (T wall − T amb ) and same
geometry under free convection, heat dissipation from vertical fin with horizontal
base was highest, horizontal fins with vertical base were lowest and the other setup
was intermediate. Optimum fin spacing was 10.5 ± 1 mm with duralumin fin material.
Leung and Probert [5] studied the influence of fin height (10 mm, 17 mm), and
the authors concluded that the variation in fin height and temperature difference
(T wall − T amb ) did not affect the optimum spacing of fin values. Leung and Probert [6]
experimentally studied the effect of spacing between consecutive vertical rectangular
fin arrays under natural convection heat transfer at steady state. 3% increase in the
dissipation rate was seen with material saving of fin for a gap width of 18 ± 2 mm.
Yuncu and Guvenc [7] studied vertical base rectangular fin array arrangement
under natural convection mode. It was found that experiments with vertical base
were efficient than that of horizontal base. The influence of height and spacing
of fins and temperature difference (T base − T amb ) on the heat dissipation rate was
observed for different power inputs. From the results, it was concluded that the
thermal performance of fin arrays is majorly influenced by fin spacing.
Awasarmol and Pise [8] investigated rectangular fin arrays under natural convection, and the results were compared with and without perforation. Experiments were
conducted for 0–90° inclinations by changing perforation diameter (4–12 mm).
For the HS with 45° inclination and 12 mm perforation diameter, 32% increase
in convection coefficient was noted along with the material saving of 30%.
R. V. Unni and M. Sreedhar Babu
under natural convection, the use of geometry which results in optimum cooling rate
becomes significant. Therefore, the geometry of HS promoting optimum cooling
with least material is an area to explore. Thus, the design of HS is considered as an
important subject to pursue and contribute. Besides this, materials used for fins should
possess good thermal conductivity to facilitate better heat transfer. Materials, such as
aluminum, copper, silver, are known for their higher thermal conductivity. However,
among these aluminum is cost-effective. In the following sections, discussions related
to experimental method and the outcome of experiments are presented.
2 Literature Review
Starner et al. [1] performed experimental studies on rectangular fin arrays and
compared the results with Elenbass [2]. Retaining the fin length (10 in.), fin width
(5 in.) and fin height (0.04 in.) constant, he varied fin spacing (0.25–0.313 in.) and
number of fins (15 and 17). For different inclinations, flow patterns were studied and
observed that the use of optimum number of fins increases the rate of heat dissipation. It was also observed that, for small spacing, due to interference in the boundary
layer, i.e., airflow obstruction, convection coefficient values were less as compared
to wider values of spacing. Average heat-transfer coefficient values [3] for shorter
fin (5 in.) length were higher as compared to longer (10 in.) fin length.
Leung et al. [4] carried out experimental work considering three cases, namely
vertical fins with horizontal base, vertical fins with vertical base and horizontal fins
with vertical base. For constant temperature difference (T wall − T amb ) and same
geometry under free convection, heat dissipation from vertical fin with horizontal
base was highest, horizontal fins with vertical base were lowest and the other setup
was intermediate. Optimum fin spacing was 10.5 ± 1 mm with duralumin fin material.
Leung and Probert [5] studied the influence of fin height (10 mm, 17 mm), and
the authors concluded that the variation in fin height and temperature difference
(T wall − T amb ) did not affect the optimum spacing of fin values. Leung and Probert [6]
experimentally studied the effect of spacing between consecutive vertical rectangular
fin arrays under natural convection heat transfer at steady state. 3% increase in the
dissipation rate was seen with material saving of fin for a gap width of 18 ± 2 mm.
Yuncu and Guvenc [7] studied vertical base rectangular fin array arrangement
under natural convection mode. It was found that experiments with vertical base
were efficient than that of horizontal base. The influence of height and spacing
of fins and temperature difference (T base − T amb ) on the heat dissipation rate was
observed for different power inputs. From the results, it was concluded that the
thermal performance of fin arrays is majorly influenced by fin spacing.
Awasarmol and Pise [8] investigated rectangular fin arrays under natural convection, and the results were compared with and without perforation. Experiments were
conducted for 0–90° inclinations by changing perforation diameter (4–12 mm).
For the HS with 45° inclination and 12 mm perforation diameter, 32% increase
in convection coefficient was noted along with the material saving of 30%.