scholarly journals Forced Convection of Al2O3–Cu, TiO2–SiO2, FWCNT–Fe3O4, and ND–Fe3O4 Hybrid Nanofluid in Porous Media

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2902 ◽  
Author(s):  
M. Z. Saghir ◽  
M. M. Rahman
Keyword(s):  
Porous Media ◽  
Ethylene Glycol ◽  
Forced Convection ◽  
Numerical Code ◽  
Hybrid Nanofluid ◽  
Pumping Power ◽  
Cooling Process ◽  
Constant Flow Rate ◽  
New Class ◽  
Hybrid Fluid

Adding nanoparticles to fluid has led to a new class of fluids named as nanofluids. Different concentrations and its effective cooling have attracted many engineering applications to test this new fluid. Lately, important heat enhancement has been observed by dispersing two distinct nanoparticles in the regular fluid. This type of hybrid nanofluid has led researchers to study its effectiveness in the cooling process. Here, we experimentally studied the forced convection of Al2O3–Cu hybrid nanofluid in porous media at a constant flow rate and heating condition. The numerical code after being calibrated with the experimental results is used to predict the effectiveness in cooling by using a set of hybrid fluid of TiO2–SiO2, MWCNT–Fe3O4, and ND–Fe3O4 at different concentrations. In the experiment, we used water and a water–ethylene glycol mixture as base fluids. The results revealed that the hybrid fluid contributed to heat enhancement levied increased pumping power. However, the index of efficiency, obtained by combining the Nusselt number and pressure drop, indicated that the best hybrid fluid for such an application is ND–Fe3O4 in the water–ethylene glycol mixture.

A Study of Thermal Effectiveness of Laminar Forced Convection of Nanofluids

2012 ◽  
Author(s):  
Leyuan Yu ◽  
Dong Liu
Keyword(s):  
Forced Convection ◽  
Base Fluid ◽  
Theoretical Studies ◽  
Constant Flow ◽  
Pumping Power ◽  
Constant Flow Rate ◽  
Figures Of Merit ◽  
Convective Thermal ◽  
Laminar Forced Convection ◽  
Flow Constraints

Recent theoretical studies show that the convective thermal performance of nanofluids in cooling applications depends crucially on the effective thermophysical properties and, if the performance comparisons are made under different flow constraints, contradictory conclusions can be drawn regarding the effectiveness of the same nanofluid. In this work, an experimental study was reported on the laminar forced convection of Al2O3-water and Al2O3-Polyalphaolefin (PAO) nanofluids through a circular minichannel. Based on the experimental data, the thermal effectivenesses of the nanofluids were evaluated critically using various figures of merit (FOM) under three typical flow constraints, i.e., constant flow rate, constant Reynolds number and constant pumping power. Although the nanofluids enhance convective heat transfer, the results show their overall thermal effectiveness is adversely affected by the combined effects of higher viscosity and lower specific heat. In particular, when the cooling application is constrained by the constant pumping power condition, there is virtually no difference in the thermal performances between the base fluid and the nanofluids.

Heat transfer and second law analysis of ethylene glycol based ternary hybrid nanofluid under laminar flow

2021 ◽  
pp. 1-45
Author(s):  
Lingala Sundar ◽  
Kottutu V.V. Chandra Mouli ◽  
Zafar Said ◽  
Antonio C.M. Sousa
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Laminar Flow ◽  
Ethylene Glycol ◽  
Physical Properties ◽  
Friction Factor ◽  
Base Fluid ◽  
Hybrid Nanofluid ◽  
Pumping Power ◽  
Thermo Physical Properties

Abstract Experiments were conducted to evaluate the thermal and frictional entropy generation and exergy efficiency of rGO-Fe3O4-TiO2 hybrid nanofluid in a circular tube under laminar flow. The ternary nanoparticles are synthesized using the sol-gel technique and characterized by XRD, SEM, and FTIR. The stable ethylene glycol based ternary hybrid nanofluid were prepared and thermo-physical properties, heat transfer, friction factor, and pumping power at various particle weight concentrations (0.05% to 0.2%) and Reynolds number (211 to 2200) were investigated. Enhancement in the thermal conductivity and viscosity of 10.6% and 108.3% at ψ = 0.2% and at 60°C over the base fluid were obtained. Similarly, Nusselt number is enhanced to 17.78%; heat transfer coefficient is enhanced to 24.76%; thermal entropy generation is reduced to 19.85%; exergy efficiency enhancement of 6.23% at ψ = 0.2% and at Re = 1548 is achieved. The pressure drop, pumping power, and friction factor is augmented to 13.65%, 11.33%, and 16% at ψ = 0.2% and at Re = 221.1 over the base fluid. The overall thermal performance of the system is enhanced to 14.32%. New equations are modeled to evaluate the thermo-physical properties, Nusselt number, and friction factor.

Impact of non-similar modeling on Darcy-Forchheimer-Brinkman model for forced convection of Casson nano-fluid in non-Darcy porous media

2021 ◽  
Vol 125 ◽  
pp. 105312
Author(s):  
Umer Farooq ◽  
Muzamil Hussain ◽  
Muhammad Ahsan Ijaz ◽  
Waseem Asghar Khan ◽  
Fozia Bashir Farooq
Keyword(s):  
Porous Media ◽  
Forced Convection ◽  
Brinkman Model ◽  
Nano Fluid

Open-air synthesis of oligo(ethylene glycol)-functionalized polypeptides from non-purified N-carboxyanhydrides

2021 ◽  
Author(s):  
Zhengzhong Tan ◽  
Ziyuan Song ◽  
Tianrui Xue ◽  
Lining Zheng ◽  
Lei Jiang ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Protein Absorption ◽  
New Class

With PEG-like properties, such as hydrophilicity and stealth effect against protein absorption, oligo(ethylene glycol) (OEG)-functionalized polypeptides have emerged as a new class of biomaterials alternative to PEG with polypeptide-like properties....

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