Experimental and theoretical investigation of heat transfer characteristics of cylindrical heat pipe using Al2O3\u2013SiO2/W-EG hybrid nanofluids by RSM modeling approach

T Balakrishnan,R Vidhya,B Suresh Kumar

doi:10.1186/s44147-021-00034-8

Abstract

Nanofluids are emerging two-phase thermal fluids that play a vital part in heat exchangers owing to its heat transfer features. Ceramic nanoparticles aluminium oxide (Al2O3) and silicon dioxide (SiO2) were produced by the sol-gel technique. Characterizations have been done through powder X-ray diffraction spectrum and scanning electron microscopy analysis. Subsequently, few volume concentrations (0.0125–0.1%) of hybrid Al2O3–SiO2 nanofluids were formulated via dispersing both ceramic nanoparticles considered at 50:50 ratio into base fluid combination of 60% distilled water (W) with 40% ethylene glycol (EG) using an ultrasonic-assisted two-step method. Thermal resistance besides heat transfer coefficient have been examined with cylindrical mesh heat pipe reveals that the rise of power input decreases the thermal resistance and inversely increases heat transfer coefficient about 5.54% and 43.16% respectively. Response surface methodology (RSM) has been employed for the investigation of heat pipe experimental data. The significant factors on the various convective heat transfer mechanisms have been identified using the analysis of variance (ANOVA) tool. Finally, the empirical models were developed to forecast the heat transfer mechanisms by regression analysis and validated with experimental data which exposed the models have the best agreement with experimental results.

Highlights

Nanofluid is an efficient working medium for heat transfer applications in automobile industries, solar collectors, air conditioning, nuclear reactors, microelectronics, computers, and cooling electronic devices [1]
Aluminium oxide (Al2O3) and Silicon dioxide (SiO2) nanoparticles characterization studies Powder X-ray diffraction method analysis Figure 2a and b illustrates XRD pattern of aluminium oxide and silicon dioxide nanoparticles made through sol-gel manner
The peak at 2θ = 22° indicates that SiO2 particles were formed by small nanocrystals and the slight broadening of the peak is due to the effect of smaller grain size

Summary

Introduction

Nanofluid is an efficient working medium for heat transfer applications in automobile industries, solar collectors, air conditioning, nuclear reactors, microelectronics, computers, and cooling electronic devices [1]. Yıldız et al [1] compared the hypothetical and experimental thermal conductivity models and evaluated aqueous-based Al2O3/SiO2 nanofluids efficiency with heat pipe. They observed no significant heat transfer results. Researchers proposed RSM statistical modeling to estimate the various nanofluids’ thermal properties based on input parameters such as temperatures and mass volume concentrations They analyzed the efficiency as well as the performance of heat transfer liquids in detail and illustrated the proposed models were agreed to the experimental data [37,38,39,40]. New regression correlations were established using the experimental results for the assessment of thermal resistance besides heat transfer coefficient that is not noticed in the literature widely

Methods

Results and discussion

Literature

Conclusions

Experimental results using heat pipe