Numerical Study of the Effect of the Reynolds Numbers on Thermal and Hydrodynamic Parameters of Turbulent Flow Mixed Convection Heat Transfer in an Inclined Tube

Vahidinia, Farhad; Miri, Mohadeseh

doi:10.5545/sv-jme.2015.2818

Cited by 10 publications

(8 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Case 1 has the smallest inner diameter of absorber tube so the oil velocity in the tube was greatest, and the flow became more turbulent. This simulation result has a good agreement with the study by Vahidinia and Miri [23] where they reported that the thermal performance in turbulent pipe flow rises with increasing Reynolds number since the heat transfer coefficient increases with the increase of the Reynolds number. Therefore, it is determined that the HCE size of Case 1 is appropriate for the PTC.…”

Section: Sizing Of the Ptcsupporting

confidence: 90%

Sizing a Parabolic Trough Collector for a Micro Solar Organic Rankine Cycle

Chai

Jung

2019

Jurnal Teknologi

View full text Add to dashboard Cite

There are many remote villages in Malaysia that are not connected to an electric grid, and are dependent on expensive diesel generator sets (gensets) in their daily activities. Malaysia, a tropical country, has the potential to promote solar power generation in these isolated areas. The organic Rankine cycle (ORC) using solar thermal energy as the heat source could be an attractive approach to off-grid power generation. In this study, a 1 kWe solar ORC with a parabolic trough collector (PTC) is proposed. The ORC utilizes R245fa as the working fluid and Therminol VP1 as the heat transfer medium between the PTC and ORC. Thermodynamic analysis of the ORC is performed, predicting the performance of the ORC and the operating conditions of the PTC. Based on the design requirements of the PTC from the power cycle analysis, process of sizing the PTC is conducted via a numerical model. Seven sets of heat collector elements (HCE) are examined. The effects of absorber tube material, selective coating on the outer surface of the absorber tube, and the absorber tube diameter on the PTC performance are presented. Simulation results show that HCE with 6 mm of SS316L absorber tube, enclosed with 11 mm of Pyrex borosilicate glass tube, has the highest collector efficiency of 62.25%. The receiver length required is 8.05 m and the aperture width of the collector is 3.54 m. Further study is recommended to select a thermal storage system for night-time operation of the ORC.

show abstract

Section: Sizing Of the Ptcsupporting

confidence: 90%

Sizing a Parabolic Trough Collector for a Micro Solar Organic Rankine Cycle

Chai

Jung

2019

Jurnal Teknologi

View full text Add to dashboard Cite

show abstract

“…4. The trend suggests that Nu increases linearly with Re as reported in the literature for different heat exchangers [29][30][31] but in each case the slopes varies due to different geometric and flow conditions. Hot inlet temperature in each experiment was kept constant at about 25°C in all experiments but we also checked it for some other values and the correlation developed was not affected by changing its value.…”

Section: Resultssupporting

confidence: 74%

Experimental investigation of heat transfer performance in a triangular pitch plain tubes bundle

Kim¹,

Ishaque²

2017

Sixth International Conference on Advances in Civil, Structural and Mechanical Engineering - ACSM 2017

View full text Add to dashboard Cite

In the present study Nu correlation of tube side for triangular pitch plain tubes bundle is proposed. The performance of the current heat exchanger is investigated experimentally in a single phase. Ten different experiments were conducted for different flow rates in order to study the effect of different parameters on heat transfer coefficient correlation. Hot inlet temperature was kept at 25°C whereas, cold inlet temperature was kept at 15°C. Reynolds number was varied from 2300-20,000. Matlab code for modified Wilson plot method was also developed to overcome the assumption of Reynolds exponent in Wilson plot method. All the required parameters like temperature, flow rate and pressure were calculated using calibrated instruments. The tube-side Nu correlation was proposed and compared with existing correlations. The maximum difference came out to be 3.8% and 5.7% with Seider and Tate and Dittus-Boelter correlations respectively whereas, difference with Gnielinski correlation in turbulent region was less than 12% but for transition region it was more than 20%.

show abstract

“…Thermophoresis is a phenomenon by which the nanoparticles in the base fluid will be thrusted from hotter to the colder region due to the temperature gradient exists in the fluid. Thermophoretic velocity of nanoparticles accounts all the three aforesaid parameters, and it can be estimated through the thermophoretic mobility of nanoparticles [21] as given in Equation ( 7):…”

Section: Solutionmentioning

confidence: 99%

Effect of Thermophoresis on Heat Diffusion in Isobutane/Copper‐Oxide Nanofluid under Pool Boiling Condition: Numerical Investigation

Feroskhan

Venugopal

Almakayeel

et al. 2022

Journal of Nanomaterials

View full text Add to dashboard Cite

Understanding thermophoresis in nanorefrigerants stands challenging for a long period despite the phenomenon is attributed for the motion dynamics of particles in nanofluids. Influence of thermophoretic mobility of copper-oxide nanoparticles on the heat transfer behavior of isobutane (R600a) refrigerant is reported in this work. Pool boiling of the isobutane/copper-oxide nanofluid is numerically simulated in computational fluid dynamics utilizing both single and two-phase approaches. Mobility of particles in the saturated refrigerant is studied, and the time scales associated with (Brownian and momentum) diffusions are numerically solved. The temperature contour of the liquid pool is validated with the experimental data, and the properties of the nanorefrigerant such as thermal conductivity, viscosity, and specific heat are estimated in ANSYS Fluent. 5% increase in thermal conductivity and marginal reduction in specific heat of the nanorefrigerant for 0.01% volume fraction of copper-oxide nanoparticles is witnessed. Mobility of particles due to temperature gradient is found higher near the heater; however, thermophoretic velocity is predicted to be lower because of the narrow temperature gradient. Numerical results showed that the time scale for momentum diffusion is shorter (in the order of e+03) than Brownian diffusion, and hence the momentum diffusion is found to be the predominant mode of heat transfer in nanorefrigerant.

show abstract

Numerical Study of the Effect of the Reynolds Numbers on Thermal and Hydrodynamic Parameters of Turbulent Flow Mixed Convection Heat Transfer in an Inclined Tube

Cited by 10 publications

References 32 publications

Sizing a Parabolic Trough Collector for a Micro Solar Organic Rankine Cycle

Sizing a Parabolic Trough Collector for a Micro Solar Organic Rankine Cycle

Experimental investigation of heat transfer performance in a triangular pitch plain tubes bundle

Effect of Thermophoresis on Heat Diffusion in Isobutane/Copper‐Oxide Nanofluid under Pool Boiling Condition: Numerical Investigation

Contact Info

Product

Resources

About