| Abstrak/Abstract |
The objective of the present research is to investigate the impact of flow patterns on the heat transfer process of
gas-Newtonian/non-Newtonian liquid two-phase flow in a horizontal microchannel. A square copper micro
channel with a side length of 8 × 10
4
m was employed. Various working liquids were examined, including
water, 0.2 %wt CMC (Carboxymethyl Cellulose) aqueous solutions, 0.4 %wt CMC, and 0.2 %wt XG (Xanthan
Gum). Nitrogen was used as the working gas. The liquid apparent velocity, j
m/s, while the gas apparent velocity, j
G
L
was varied in the range of 0.05–1.0
ranged from 0.26 to 7.81 m/s. Some of DPTs (Differential Pressure
Transducers) were used to measure the pressure drop. A constant heat flow of 12.08 kW/m
2
was maintained, and
the temperature of the channel's wall was monitored using a T-type thermocouple located on the copper channel
as the heating section. Flow patterns were captured with a high-speed video camera. Results revealed four
distinct flow patterns: BB (bubbly), SL (slug), SA (slug-annular), and CH (churn) flow. The coefficient of
convective heat transfer in the CH flow exhibited the highest value in comparison with other observed flow
patterns. However, the CH flow pattern also resulted in the highest-pressure gradient in both the upstream
heating and heating sections. Furthermore, correlations proposed by Kawahara et al. (2011) and Rezkallah
(1986) demonstrated good agreement with the present experimental data for pressure gradient and coefficient of
convective heat transfer
h
TP
, respectively. Despite this, the SL flow exhibited the best performance index for the
heat transfer process in the present gas-non-Newtonian two-phase flow. Furthermore, the use of a non-
Newtonian liquid in the present experimental study suggests its potential application as a cooling fluid |
