2011 International Conference on Alternative Energy in Developing Countries and Emerging Economies
- 130 -
Abstract
-- In the present work, the single-phase heat
transfer of water flowing through the multiport minichannel
heat exchanger was experimentally studied. The test section
tube was made from the extruded multiport aluminium tube
with hydraulic diameter of 1.2 mm and 24 number of
channels. The 180 W DC heating plate with heating surface
area of 80 cm
2
was used to supply heat flux to the test
section. The single-phase heat transfer performance of
water is experimentally determined based on the constant
heat flux for each condition. The experiments have been
carried out by varying the heat flux, the volume flow rate,
and the water temperature. The Reynolds numbers of water
were approximately 450
–
1800. The
cooling’s law of Newton
method was applied to investigate the heat transfer and the
experimental results were compared with the classical
correlations. It is found that the correlation of Disttus-
Boelter (-) show good agreement with the experimental data.
Index
Terms--
Single-phase
flow;
Multiport
minichannel;Heat transfer coefficient; Heat exchanger.
I.
I
NTRODUCTION
The single-phase heat transfer performance of the
multiport minichannel has been studied by some
researchers, and some examples of the studies are
described as follows.
Adams et al. [1] investigated single-phase forced
convection of water in circular microchanels with
diameters of 0.76 and 1.09 mm. They found that the
experimental heat transfer coefficient were higher than
those predicted by the classical correlations such as the
Gnielinski correlation [7]. In 2002, Qu and Mudawar [11]
experimentally and numerically investigated the heat
transfer characteristics of a single-phase microchannel
heat sink. The heat sink consisted of an array of
rectangular microchannel
with 231μm wide and 713 μm
deep. They performed at the range of Reynolds number
of 139 to 1672. The there-dimensional heat transfer
characteristics were analyzed numerically by solving the
conjugate heat transfer problem.
Warrier et al. [12] performed experimental study of
forced convection in a small rectangular channels using
FC-84 as the test fluid. They used five parallel channels
with hydraulic diameter
d
h
= 0
.
75 mm and length-to-
diameter ratio
L
h
/d
h
= 433
.
5 test as a test section. The
experiments were conducted with uniform heat fluxes by
applying at the top and bottom surfaces. They found that
the measured results were well agreement with the
This work was supported by Graduated School, and The
Research and Development Institute, Thaksin University.
numerical results obtained from Kays and Crawford [8].
In 2004, Owhaib and Palm [10] investigated the heat
transfer characteristics for single-phase forced convection
for R134a through the circular microchannels. Their
results show a good agreement with the classical
correlations Dittus-Boelter [3], and Gnielinski [7].
In 2005, Lee et al. [9] investigated the experimental
study the single-phase de-ionized water heat transfer
characteristics in rectangular microchannels with range in
width from 194 to 534 μm and the depth of five times of
the width in each case. They compared the experimental
results with the results from numerical calculation, they
found that the measured results are lower those obtained
from numerical calculation. They gave the reason that the
numerical calculation did not include the conduction in
the thin wall.
Fernando et al. [5] investigated the single-phase heat
transfer in shell-and-tube heat exchanger. The test section
was made from extruded aluminium minichannel tube
with hydraulic diameter of 1.42 mm for tube side and
3.62 mm for shell side. They employed the Wilson plot
method to calculate the single-phase heat transfer
coefficient on both tube and shell side. They found that
the Nusselt numbers proposed by Gnielinski [7] was well
agreement with their experimental data within 5%
accuracy for the Reynolds number rage of 2300-6000. In
range of low Reynolds number, 170-1200, they found
that none of the previous correlations wear predicted the
Nusselt numbers. They also reported that for shell-side
Nusselt numbers were found to be considerably higher
than those predicted by correlations from the literature.
Garcia-Hernando et al. [6] conducted the experimental
investigation of single-phase liquid in microchannel heat
exchanger. They used two different sizes heat
exchangers, 100×100
μm and 200×200
μm, as the test
section. They performed with the wide range of laminar
Reynolds number. They compared the measured results
with the results obtained from the conventional theory.
They concluded that the results show a good agreement
with the general theory and no special effect related to the
small dimension of the channels was observed.
II. NOMENCLATURE
A
area (m
2
)
C
p
specific heat at constant pressure (kJ/kg K)
d
h
hydraulic diameter (m)
h
heat transfer coefficient (W/m
2
K)
m
mass flow rate (kg/s)
Single-Phase Heat Transfer in a Multiport
Minichannel Tube Heat Exchanger
Teeradeth Yaibok
*
, Jatuporn Keaw-on
*
and Thawatchai Tepnual
**
*
Thermal-Fluid Lab, Physics Department, Thaksin University, (
Thailand
)
**
Physics Department, Faculty of Science, Thaksin University, (
Thailand)
