TY  - JOUR
T1  - Flow and Thermal Mechanisms in Receiver Tube of Parabolic Trough
Collectors with Rings Axially Connected Together and Radially
Connected to the Inner Tube Surface
AU - Abdulhamed, Ali Jaber AU - Mariah Adam, Nor AU - Abidin Ab-Kadir, Mohd Zainal AU - Aziz Hairuddin, Abdul 
JO  - Journal of Engineering and Applied Sciences
VL  - 15
IS  - 3
SP  - 762
EP  - 772
PY  - 2020
DA  - 2001/08/19
SN  - 1816-949x
DO  - jeasci.2020.762.772
UR  - https://makhillpublications.co/view-article.php?doi=jeasci.2020.762.772
KW  - Thermal mechanism
KW  -receiver tube
KW  -ring baffles inserted
KW  -parabolic trough collector
KW  -flow
mechanism
KW  -generated
AB  - Artificial obstructions on the underside of receiver tubes can increase the heat transfer coefficient
between the receiver tubes (Heat Exchanger, HX) of Parabolic Trough Collectors (PTCs) and water as a
working fluid. In this study, we numerically and experimentally tested the behavior of laminar mixed
convective heat transfer in HX tube installed with baffles. These baffles are rings that are connected together
axially and connected radially to the inner tube surface. Using ANSYS fluent Version 15.0, we performed
computation fluid dynamics modeling to achieve heat transfer enhancement in HX tubes equipped with
turbulator baffles under laminar flow conditions. Moreover, the effects of Pitch ratio (P/D) = 3, 6 and 10 and
Reynolds number Re#480 were recorded. The novel application of the rings that are connected axially together
and radially to the inner tube surface contributes to the long-term storage of thermal energy and promotes heat
transfer via. conduction from the tube surface to the center line of the water flow within a short period. In the
study, the baffles generated a vortex to increase the Nusselt number (Nu) inside the HX. To simulate heat flux,
we calculated the constant wall heat flux of the receiver tube using an electric heater. Results indicated that
using 20 rings as baffles instead of plain tubes improves heat transfer by up to 75%. As P/D decreased and re
increased, the heat transfer rate, friction factor (f) and Thermal Enhancement Factor (TEF) increased.
ER  -