scholarly journals Experimental Study of Al2O3 Nanofluids on the Thermal Efficiency of Curved Heat Pipe at Different Tilt Angle

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
S. Razvarz ◽  
R. Jafari
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Heat Pipe ◽  
Inclination Angle ◽  
Tilt Angle ◽  
Thermal Efficiency ◽  
Volume Concentration ◽  
Pure Water ◽  
Heat Pipes ◽  
Particle Volume

This paper represents an experimental study about the effect of curves related to thermosyphons and heat pipes with different active fluids and inclination angle at the thermal efficiency. The nanofluid utilized in this work is an aqueous soluble of Al2O3 nanoparticles with 35 nm diameter in pure water. The test saturation level of nanoparticles is 0%, 1%, and 3%wt. All the experiments were conducted and repeated at inclination angle of 30°, 60°, and 90° (vertical). The article presents the gravity impacts on the heat transfer characteristics in different angles and the effects of working fluids and tilt angle of heat pipe tube by the addition of nanoparticles and weight fractions on the thermal efficiency of heat pipe at different inclination. According to the experimental results, the heat pipe at the tilt angle of 60° generates the superior results. At a particle volume concentration of 1%, the use of Al2O3/water nanofluid gives significantly higher heat transfer.

An Experimental Study on Improvement in Thermal Efficiency of Mesh Wick Heat Pipe

2014 ◽  
Vol 592-594 ◽  
pp. 1423-1427 ◽  
Author(s):  
G. Kumaresan ◽  
S. Venkatachalapathy ◽  
Indraneel C. Naik
Keyword(s):  
Experimental Study ◽  
Heat Pipe ◽  
Inclination Angle ◽  
Tilt Angle ◽  
Thermal Efficiency ◽  
Cuo Nanoparticles

This study aims to investigate the influence of inclination angle and concentration of nanoparticles on the improvement in heat pipe thermal efficiency. Spherical shaped, 40 nm size CuO nanoparticles are used in this study and its physical and thermal chracteristics are investigated. The results are compared with a heat pipe using DI water at horizontal position.The thermal efficiency is improved by increasing the tilt angle and mass of particles dispersed in DI water. The improvement in thermal efficiency obtained are 20.59, 35.92 and 32.57% respectively for 0.5, 1.0 and 1.5 wt% of CuO nanofluids and 60° inclination angle.

Energy and Exergy Analysis of Shell and Coil Heat Exchanger Using Water Based Al2O3 Nanofluid Including Diverse Coil Geometries: An Experimental Study

2020 ◽  
Vol 9 (1) ◽  
pp. 13-23
Author(s):  
Samir M. Elshamy ◽  
Mohamed T. Abdelghany ◽  
M. R. Salem ◽  
O. E. Abdellatif
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Exergy Analysis ◽  
Volume Concentration ◽  
Pure Water ◽  
Cone Angle ◽  
Particle Volume ◽  
Water Based ◽  
Coil Heat

The aim of this research is to investigate experimentally the characteristics of the convective heat transfer and exergy analysis of pure water and water based Al2O3 nanofluid through helical coiled tubes (HCTs) and conical coiled tubes (CCTs) inside shell and coil heat exchangers. HCT and CCT fabricated with different coil torsions (λ) ranges from 0.0202 to 0.052 with different two angles (0° and 45°) while have the same curvature ratio (δ = 0.0564). The effects of mean coil torsion, the cone angle and nanoparticles volume concentration on the thermal performance were investigated. Results indicated that the overall heat transfer coefficient (Uov), convection heat transfer coefficient (ht), the tube side Nusselt number (Nut), effectiveness (ɛ) and exergy efficiency (ηex) of nanofluids are higher than those of the pure water at same flow condition, and this increase goes up with the increase in particle volume concentration (ϕ). The results also showed that Uov, ht, Nut, ɛ and ηex increases by decreasing the coil torsion from 0.052 to 0.0202. Correlations for Nut as a function of the investigated parameters are obtained.

Effect of Nanoparticle and Inclination Angle at Thermal Efficiency in Heatpipes

2021 ◽  
pp. 1271-1288
Author(s):  
Sina Razvarz ◽  
Raheleh Jafari ◽  
Cristóbal Vargas Jarillo ◽  
Alexander Gegov
Keyword(s):  
Heat Pipe ◽  
Inclination Angle ◽  
Thermal Efficiency ◽  
Pure Water ◽  
Thermal Characteristics ◽  
Nano Particles ◽  
Al2o3 Nanoparticles ◽  
Al2o3 Nanoparticle ◽  
Nano Fluids

This chapter demonstrated an experimental study about the effect of inclination angle and nano particles in active fluids and curves related to thermosiphons and heatpipes. In this context, the chapter gives a brief overview of the effect of nano fluids on thermal conductivity and thermal efficiency enhancement of a heat pipe on the different operating state and next idea is studying of efficacy related to the inclination angle of the heat pipe. In this book chapter, there is an experimental investigation employing Al2O3 nanoparticle in order to study the enhancement of thermal characteristics of a heat tube in different inclination angle. Three cases, for Al2O3 nanoparticles in water with volume concentrations 1%, 2%, and 3% are considered and results are compared with the thermal performance of the heat pipe filled with pure water. The result of each case will present in the different angular of pipeline and clearly will show the effect of the gravity in the pipeline.

Analysis of Heat Transfer Factors for a Heat Pipe Absorber Array Connected to a Common Manifold

1986 ◽  
Vol 108 (1) ◽  
pp. 11-16 ◽  
Author(s):  
J. R. Hull
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Thermal Efficiency ◽  
Transfer Rate ◽  
Heat Pipes ◽  
Maximum Efficiency ◽  
Pipe Surface ◽  
Transfer Factors ◽  
Collector Efficiency ◽  
Flow Through

Heat transfer factors and thermal efficiency are calculated for a heat pipe absorber array connected to a common manifold. Arrays with less than ten heat pipes are shown to have significantly less efficiency than a conventional flow-through collector. Efficiency is also sensitive to the heat transfer rate per unit temperature difference from the heat pipe fluid to the manifold fluid divided by that from the heat pipe surface to the ambient, with maximum efficiency occurring for ratios greater than 100.

scholarly journals Thermal characteristics of grooved heat pipe with hybrid nanofluids

2011 ◽  
Vol 15 (1) ◽  
pp. 195-206 ◽  
Author(s):  
W.S. Han ◽  
S.H. Rhi
Keyword(s):  
Heat Transfer ◽  
Thermal Resistance ◽  
Heat Pipe ◽  
Volume Concentration ◽  
Pure Water ◽  
Water System ◽  
Cooling Water ◽  
Thermal Characteristics ◽  
Transient State ◽  
Hybrid Nanofluids

In the present study, the specially designed grooved heat pipe charged with nanofluids was investigated in terms of various parameters such as heat transfer rate(50-300 W with 50 W interval), volume concentration(0.005%, 0.05%, 0.1%, and hybrid combinations), inclination(5?, 45?, 90?), cooling water temperature (1?C, 10?C, and 20?C), surface state, transient state and so on. Hybrid nanofluids with different volume concentration ratios with Ag-H2O and Al2O3-H2O were used as working fluids on a grooved heat pipe(GHP). Comparing with the pure water system, nanofluidic and hybrid nanofluidic system shows greater overall thermal resistance with increasing nano-particle concentration. Also hybrid nanofluids make the system deteriorate in terms of thermal resistance. The post nanofluid experimental data regarding GHP show that the heat transfer performance is similar to the results of nanofluid system. The thermal performance of a grooved heat pipe with nanofluids and hybrid nanofluids were varied with driving parameters but they led to worse system performance.

Heat Transfer Enhancement in Microchannel Using Nanofluids

2013 ◽  
Vol 465-466 ◽  
pp. 536-540
Author(s):  
Khairul Afif Fadzin ◽  
Ann Lee
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Thermal Performance ◽  
Heat Transfer Performance ◽  
Volume Concentration ◽  
Pure Water ◽  
Transfer Performance ◽  
Transfer Enhancement ◽  
Particle Volume ◽  
Better Than

Numerical investigation of heat transfer enhancement in two-dimensional microchannel heat sink (MCHS) using Al2O3-water, CuO-water and TiO2-water was conducted. The effect of different type of nanoparticles at particle volume concentration of 1%, 2% and 5% on the thermal performance in the MCHS was examined. The thermal performance is increased when nanofluids with high thermal conductivity and low dynamic viscosity was used. As the particle volume concentration increases, the heat transfer performance also improved. The result shows that the heat transfer performance of all the nanofluids used in this study was better than that of pure water. Overall, nanofluids with Al2O3-water at 5% particle volume concentration show the best cooling performance.

scholarly journals Numerical Study of Laminar Flow Forced Convection of Water-Al2O3Nanofluids under Constant Wall Temperature Condition

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Hsien-Hung Ting ◽  
Shuhn-Shyurng Hou
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Volume Concentration ◽  
Numerical Study ◽  
Pure Water ◽  
Particle Volume ◽  
Constant Wall Temperature ◽  
Water Based

This numerical study is aimed at investigating the forced convection heat transfer and flow characteristics of water-based Al2O3nanofluids inside a horizontal circular tube in the laminar flow regime under the constant wall temperature boundary condition. Five volume concentrations of nanoparticle, 0.1, 0.5, 1, 1.5, and 2 vol.%, are used and diameter of nanoparticle is 40 nm. Characteristics of heat transfer coefficient, Nusselt number, and pressure drop are reported. The results show that heat transfer coefficient of nanofluids increases with increasing Reynolds number or particle volume concentration. The heat transfer coefficient of the water-based nanofluid with 2 vol.% Al2O3nanoparticles is enhanced by 32% compared with that of pure water. Increasing particle volume concentration causes an increase in pressure drop. At 2 vol.% of particle concentration, the pressure drop reaches a maximum that is nearly 5.7 times compared with that of pure water. It is important to note that the numerical results are in good agreement with published experimental data.

Heat Transfer Characteristics of Self-Rewetting Fluid and its Application in Heat Pipe

2015 ◽  
Author(s):  
S. F. Wang ◽  
Y. X. Hu ◽  
Y. Zhou ◽  
W. Zhang
Keyword(s):  
Heat Transfer ◽  
Surface Tension ◽  
Heat Pipe ◽  
Pure Water ◽  
Experimental Studies ◽  
Heat Pipes ◽  
Research Field ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
High Efficient

Self-rewetting fluids (SRWFs) are non-azeotropic solutions enjoy a particular surface tension behavior — an increase in the surface tension with increasing temperature. Due to the unique property, the SRWF can spontaneously wet hotter region and enhance heat transfer. The interesting behavior makes the SRWF become the research hotspot in phase change heat transfer research field. To clarify the heat transfer characteristics of SRWF, a series of boiling experiments have been carried out by employing dilute heptanol aqueous solution as SRWF. It is found out that, the bubble size of the SRWF is much smaller than that of pure water, and the critical heat flux of SRWF is much higher than that of water, which is beneficial for application in heat pipes. To find out the heat transfer performance of SRWF in heat pipes, experimental studies are performed on oscillating heat pipe (OHP) consisting of 4 meandering turns, with heat transfer length (L) of 150 mm and inner diameter (Di) of 1.3 mm. Compared with the water, the SRWF exhibits much better thermal performance, which indicates that SRWF is a promising and useful working liquid for the application in high efficient cooling devices with micro structure.

Effect of Al2O3-Water Nanofluid on the Heat Performance of Gravity-Assisted Heat Pipe

2014 ◽  
Vol 692 ◽  
pp. 470-474
Author(s):  
Wei Wu ◽  
Shu Lei Zhao ◽  
Qiang Lin
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Thermal Performance ◽  
Heat Transfer Performance ◽  
Heating Temperature ◽  
Pure Water ◽  
Heat Pipes ◽  
Filling Ratio ◽  
The Difference ◽  
The Heat Transfer Coefficient

The aim of this paper is to investigate the effect of nanofluid on the heat transfer performance of heat pipe and to examine the difference of the thermal conductivity between pure water heat pipes and nanofluid heat pipes. In our experiments, Al2O3-water nanofluid and pure water were used as working fluids respectively in gravity-assisted heat pipes. Effects of filling ratio and heating temperature on the thermal performance of heat pipe were investigated. The thermal resistance of heat pipe was analyzed. Our results showed that nanofluid can significantly increase the heat transfer coefficient and enhance the thermal performance of heat pipe.

Sign in / Sign up

Export Citation Format

Share Document