Condensing two-phase pressure drop and heat transfer coefficient of propane in a horizontal multiport mini-channel tube: Experimental measurements

2016 ◽  
Vol 68 ◽  
pp. 59-75 ◽  
Author(s):  
Alejandro López-Belchí ◽  
Fernando Illán-Gómez ◽  
José Ramón García-Cascales ◽  
Francisco Vera-García
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Experimental Measurements ◽  
Two Phase ◽  
Channel Tube ◽  
Phase Pressure

Experimental Investigation of Heat Transfer Enhancement of Shell and Tube Heat Exchanger Using SnO2-Water and Ag-Water Nanofluids

2019 ◽  
Vol 12 (4) ◽  
Author(s):  
S. V. Sridhar ◽  
R. Karuppasamy ◽  
G. D. Sivakumar
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Convective Heat Transfer Coefficient ◽  
Two Phase ◽  
Tube Heat Exchanger ◽  
Shell And Tube

Abstract In this investigation, the performance of the shell and tube heat exchanger operated with tin nanoparticles-water (SnO2-W) and silver nanoparticles-water (Ag-W) nanofluids was experimentally analyzed. SnO2-W and Ag-W nanofluids were prepared without any surface medication of nanoparticles. The effects of volume concentrations of nanoparticles on thermal conductivity, viscosity, heat transfer coefficient, fiction factor, Nusselt number, and pressure drop were analyzed. The results showed that thermal conductivity of nanofluids increased by 29% and 39% while adding 0.1 wt% of SnO2 and Ag nanoparticles, respectively, due to the unique intrinsic property of the nanoparticles. Further, the convective heat transfer coefficient was enhanced because of improvement of thermal conductivity of the two phase mixture and friction factor increased due to the increases of viscosity and density of nanofluids. Moreover, Ag nanofluid showed superior pressure drop compared to SnO2 nanofluid owing to the improvement of thermophysical properties of nanofluid.

Microchannel Size Effects on Two-Phase Local Heat Transfer and Pressure Drop in Silicon Microchannel Heat Sinks With a Dielectric Fluid

2007 ◽  
Author(s):  
Tannaz Harirchian ◽  
Suresh V. Garimella
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Flow Boiling ◽  
Heat Sinks ◽  
Dielectric Fluid ◽  
Two Phase ◽  
Microchannel Heat Sinks ◽  
The Heat Transfer Coefficient

Two-phase heat transfer in microchannels can support very high heat fluxes for use in high-performance electronics-cooling applications. However, the effects of microchannel cross-sectional dimensions on the heat transfer coefficient and pressure drop have not been investigated extensively. In the present work, experiments are conducted to investigate the local flow boiling heat transfer in microchannel heat sinks. The effect of channel size on the heat transfer coefficient and pressure drop is studied for mass fluxes ranging from 250 to 1600 kg/m2s. The test sections consist of parallel microchannels with nominal widths of 100, 250, 400, 700, and 1000 μm, all with a depth of 400 μm, cut into 12.7 mm × 12.7 mm silicon substrates. Twenty-five microheaters embedded in the substrate allow local control of the imposed heat flux, while twenty-five temperature microsensors integrated into the back of the substrates enable local measurements of temperature. The dielectric fluid Fluorinert FC-77 is used as the working fluid. The results of this study serve to quantify the effectiveness of microchannel heat transport while simultaneously assessing the pressure drop trade-offs.

scholarly journals Experimental Study of HFE 7000 Refrigerant Condensation in Horizontal Pipe Minichannels

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6886
Author(s):  
Małgorzata Sikora ◽  
Tadeusz Bohdal ◽  
Karolina Formela
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Flux Density ◽  
Mass Flux ◽  
Internal Diameter ◽  
Two Phase ◽  
Horizontal Pipe

This article presents the results obtained from our own experimental investigations on heat exchange and pressure drop during the condensation flow of the HFE 7000 refrigerant in pipe minichannels with an internal diameter of di = 1.2–2.5 mm. The influence of vapor quality x and the mass flux density G on the two-phase flow pressure drops and heat transfer is presented. The tests were performed for the mass flux density range of G = 110–4700 kg/m2s, saturation inlet temperature of Ts = 36–43 °C and heat flux density of q = 1 ÷ 20 kW/m2. The pressure drop characteristics and heat transfer coefficient as a function of the internal diameter of minichannels are illustrated. The results of experimental research on the heat transfer coefficient and two-phase pressure drop are compared with correlations developed by other authors. The best accuracy has a comparison of experimental study with correlation of Rahman-Kariya-Miyara et al. and Mikielewicz et al.

Experimental Study of Annular and Stratified Flows in Horizontal Micro-Fin Tubes

2006 ◽  
Author(s):  
Q. Chen ◽  
R. S. Amano
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Water Film ◽  
Airflow Rate ◽  
Air Bubbles ◽  
Sieve Plate ◽  
Two Phase ◽  
The Heat Transfer Coefficient

In this paper, a new kind of evaporative heat transfer experiment for the cooling process of coolers/condensers is conducted. The design of the test coils is immersed in an air-water bubbling layer. The air-water two-phase flow passes through the tubes of the coils. Due to the motion of the air bubbles in the water, a thin water film forms on the surface of the tube. As the air bubbles pass by the tube this water film is evaporated into the air. The tubes of coil reject heat to the water film, and the evaporation of the water film rejects heat to the air bubble stream. This heat transfer mode significantly increases the heat transfer coefficient between tubes and air. The consumption of the power of a water pump can be decreased. Moreover, the airflow rate required is less than that of an air-cooled condenser. The pressure drop of air through air-water bubbling layer and the heat transfer between the tube and water are experimentally investigated in this paper. The results show that the factors affecting the pressure drop and the heat transfer coefficient involve the pore geometry of sieve plate, the height of the air-water bubbling layer, the air flow rate through the sieve plate and the heat flux of tubes. The heat transfer coefficient between tube and water is two times larger than that of falling film of water on the outer surface of tube.

Effect of the Pressure Drop Oscillation on the Local Heat Transfer Coefficient in a Heated Horizontal Pipe

2018 ◽  
Author(s):  
Il Woong Park ◽  
Maria Fernandino ◽  
Carlos Alberto Dorao
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Local Heat Transfer ◽  
Negative Slope ◽  
Working Fluid ◽  
Two Phase ◽  
Horizontal Pipe ◽  
The Heat Transfer Coefficient

Two-phase flow instabilities have been studied during the past decades. Pressure drop oscillation (PDO) shows a relatively larger amplitude oscillation compared with other instabilities. This oscillation typically occurs when the system has compressible volume and operates in a negative slope region of the pressure drop versus flow rate curve. The characteristics of the PDO has been studied experimentally and theoretically. Even though research has been performed for identifying the characteristics of the PDO, how the PDO affects the heat transfer coefficient (HTC) remain unclear. In this study, the heat transfer coefficient is experimentally studied during pressure drop oscillation. The experiment is conducted with a heated horizontal tube with 5 mm inner diameter and 2.0 meters in length, and the R-134a is used a working fluid. For the cases studied, no significant effect of the PDO on the average heat transfer coefficient was observed.

Two-Phase Crossflow and Boiling Heat Transfer in Horizontal Tube Bundles

1996 ◽  
Vol 118 (1) ◽  
pp. 124-131 ◽  
Author(s):  
R. Dowlati ◽  
M. Kawaji ◽  
A. M. C. Chan
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Void Fraction ◽  
Mass Velocity ◽  
Flow Boiling ◽  
Horizontal Tube ◽  
Two Phase ◽  
Tube Bundles

An experimental study has been conducted to determine the void fraction, frictional pressure drop, and heat transfer coefficient for vertical two-phase crossflow of refrigerant R-113 in horizontal tube bundles under saturated flow boiling conditions. The tube bundle contained 5 × 20 tubes in a square in-line array with pitch-to-diameter ratio of 1.3. R-113 mass velocity ranged from 50 to 970 kg/m2s and test pressure from 103 to 155 kPa. The void fraction data exhibited strong mass velocity effects and were significantly less than the homogeneous and in-tube flow model predictions. They were found to be well correlated in terms of the dimensionless gas velocity, jg*. The two-phase friction multiplier data could be correlated well in terms of the Lockhart–Martinelli parameter. The validity of these correlations was successfully tested by predicting the total pressure drop from independent R-113 boiling experiments. The two-phase heat transfer coefficient data were found to agree well with existing pool boiling correlations, implying that nucleate boiling was the dominant heat transfer mode in the heat flux range tested.

Two Phase Pressure Drop and Boiling Heat Transfer in Micro Pin Fin Channel

2016 ◽  
Author(s):  
Ki Moon Jung ◽  
Hee Joon Lee
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Mass Flux ◽  
Boiling Heat Transfer ◽  
Transfer Coefficients ◽  
Two Phase ◽  
Pin Fin ◽  
Boiling Heat Transfer Coefficient

In this paper, boiling experiments were conducted to study two-phase pressure drop and the heat transfer coefficient in a staggered array micro pin fin channel of degassed water at a mass flux range of 9.3 to 46.6 kg/m2s and a heat flux of 0.5 to 0.9 W/cm2. Copper was used for the pin fin array microchannel heat sink, which was 31 mm in width and 82 mm in length. Micro pin fins, of 400 μm in diameter and 700 μm in height, were manufactured using a micro milling machine on the channel block. The distance between two pin fin surfaces is 300 μm. A thin film heater, which supplies a maximum constant heat flux of 1.55 W/cm2, was attached underneath the heat sink. From the experimental results, at a vapor quality of up to 0.04, the boiling heat transfer coefficient decreased as the quality increased. Results show that the heat transfer coefficient is dependent on the mass flux. The data also showed that the pressure drop increased with increasing mass flux. The data obtained in this study were compared to the existing correlations of boiling pressure drop and heat transfer coefficients. Results showed that the correlation with boiling pressure drop of Qu and Siu-Ho[22] yielded a prediction of 21.3% average error Additionally, as a result of comparison with the four existing correlations of boiling heat transfer coefficient, all correlations had a lower prediction for the heat transfer coefficients obtained in this study. Through visualization, it was found that the bubbles generated between the fins began to grow and moved downstream. We observed a stationary vapor pocket in which bubbles did not flow.

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