Melting heat transfer in Cu-water and Ag-water nanofluids flow with homogeneous-heterogeneous reactions

This article addresses melting heat transfer in magnetohydrodynamics(MHD)nanofluid flows by a rotating disk. The analysis is performed in Cu-water and Ag-water nanofluids. Thermal radiation, viscous dissipation, and chemical reactions impacts are added in the nanofluid model. Appropriate transformations lead to the nondimensionalized boundary layer equations. Series solutions for the resulting equations are computed.The role of pertinent parameters on the velocity, temperature, and concentration is analyzed in the outputs. It is revealed that the larger melting parameter enhances the velocity profile while the temperature profile decreases. The surface drag force and heat transfer rate are computed under the influence of pertinent parameters. Furthermore, the homogeneous reaction parameter serves to decrease the surface concentration.

Hybrid Nanofluid Flow with Homogeneous-Heterogeneous Reactions

This study examines the stagnation point flow over a stretching/shrinking sheet in a hybrid nanofluid with homogeneous-heterogeneous reactions.The hybrid nanofluid consists of copper(Cu)and alumina(Al2O3)nanoparticles which are added into water to form Cu-Al2O3/water hybrid nanofluid.The similarity equations are obtained using a similarity transformation.Then,the function bvp4c in MATLAB is utilised to obtain the numerical results.The dual solutions are found for limited values of the stretching/shrinking parameter.Also,the turning point arises in the shrinking region(λ<0).Besides,the presence of hybrid nanoparticles enhances the heat transfer rate,skin friction coefficient,and the concentration gradient.In addition,the concentration gradient is intensified with the heterogeneous reaction but the effect is opposite for the homogeneous reaction.Furthermore,the velocity and the concentration increase,whereas the temperature decreases for higher compositions of hybrid nanoparticles.Moreover,the concentration decreases for larger values of homogeneous and heterogeneous reactions.It is consistent with the fact that higher reaction rate cause a reduction in the rate of diffusion.However,the velocity and the temperature are not affected by these parameters.From these observations,it can be concluded that the effect of the homogeneous and heterogeneous reactions is dominant on the concentration profiles.Two solutions are obtained for a single value of parameter.The temporal stability analysis shows that only one of these solutions is stable and thus physically reliable over time.

Note on characteristics of homogeneous-heterogeneous reaction in flow of Jeffrey fluid

This letter describes the characteristics of homogeneous-heterogeneous re- action in the boundary layer flow of a Jeffrey fluid due to an impermeable horizontal stretching sheet. An analysis is carried out through the similar values of reactant and auto catalyst diffusion coefficients. Heat released by the reaction is not accounted. The exact solution for the flow of the Jeffrey fluid is constructed. The series solution for the concentration equation is derived. The velocity and concentration fields reflecting the impact of interesting parameters are plotted and examined.

New insights into FeS/persulfate system for tetracycline elimination:Iron valence,homogeneous-heterogeneous reactions and degradation pathways

In this study,complete tetracycline(TTC)and above 50%of total organic carbon(TOC)were removed by Fe S/PS after 30 min under optimized conditions.Although free radicals and high-valent iron ions were identified to generate in the process,the apparent similarity between intermediate products of Fe S/PS,Fe/PS,and UV/PS systems demonstrated that the degradation of TTC was due to sulfate radicals(SO_(4)·^(-))and hydroxyl radicals(·OH).Based on the reaction between free radicals and organic matter,we speculated that TTC in the Fe S/PS system was decomposed and mineralized by dehydration,dehydrogenation,hydroxyl addition,demethylation,substitution,E-transfer,and ring-opening.Furthermore,a new understanding of Fe S-mediated PS activation based on stoichiometry and kinetic analysis showed that there were both homogeneous and heterogeneous reactions that occurred in the entire progress.However,due to the effect of p H on the dissolution of iron ions,the homogeneous reaction became the principal process with iron ions concentration exceeding 1.35 mg/L.This work provides a theoretical basis for the study of the degradation of TTC-containing wastewater by the iron-based advanced oxidation process.

Catalysis at the Homogeneous-Heterogeneous Chemistry Interface

1 Results Significant progress has been made in recent years in developing efficient, atom economical catalytic reactions of potential applicability to the pharmaceutical, petrochemical, and commodity chemical business sectors. In some cases, homogeneous catalytic processes offer advantages, but in others the use of heterogenized homogeneous catalysis provides a competitive advantage concerning recyclability and catalyst recovery. This presentation will consider new approaches to cyclization reactions a...

Chemically reactive and radiative von Kármán swirling flow due to a rotating disk

A new mathematical model is presented to study the heat and mass transfer characteristics of magnetohydrodynamic(MHD) Maxwell fluid flow over a convectively heated stretchable rotating disk. To regulate the fluid temperature at the surface, a simple isothermal model of homogeneous-heterogeneous reactions is employed. The impact of nonlinear thermal radiative heat flux on thermal transport features is studied. The transformed nonlinear system of ordinary differential equations is solved numerically with an efficient method, namely, the Runge-Kutta-Felberg fourth-order and fifth-order(RKF45)integration scheme using the MAPLE software. Achieved results are validated with previous studies in an excellent way. Major outcomes reveal that the magnetic flux reduces the velocity components in the radial, angular, and axial directions, and enhances the fluid temperature. Also, the presence of radiative heat flux is to raise the temperature of fluid. Further, the strength of homogeneous-heterogeneous reactions is useful to diminish the concentration of reaction.

Ru(bpy)_(3)^(2+)-sensitized{001}facets LiCoO_(2) nanosheets catalyzed CO_(2) reduction reaction with 100% carbonaceous products

Photosensitized heterogeneous CO_(2) reduction(PHCR)has emerged as a promising means to convert CO_(2) into valuable chemicals,however,challenged by the relatively low carbonaceous product selectivity caused by the competing hydrogen evolution reaction(HER).Here,we report a PHCR system that couples Ru(bpy)32+photosensitizer with{001}faceted LiCoO_(2) nanosheets photocatalyst to simultaneously yield 21.2 and 722μmol·g^(-1)·h^(-1) of CO,and 4.42 and 108μmol·g^(-1)·h^(-1) of CH4 under the visible light and the simulated sunlight irradiations,respectively,with completely suppressed HER.The experimental and theoretical studies reveal that the favored CO_(2) adsorption on the exposed Li sites on{001}faceted LiCoO_(2) surface is responsible for the completely suppressed HER.

Heterogeneous and homogeneous reactive flow of magnetite-water nanofluid over a magnetized moving plate

This model is dedicated to visualizing the nature of magnetite-water nanoliquid induced by a permeable plate having variable magnetic effect,non-linear radiation,heterogeneous and homogeneous chemically reactive species.The system of momentum,thermal and concentration expressions is formulated and transformed from the partial to ordinary differential systems by using the adequate transforms.This highly non-linear system is solved through RKF(Runge-Kutta-Fehlberg)numerical method.Important parameters such as suction/injection,magnetic,and radiation effects as well as other relevant parameters are investigated.The graphs show that the rise in radiation parameter numerically improves the thermal distribution,implying a faster heat transfer rate.Non-linear radiation has greater effect on temperature than the linear radiation.While the volume concentration effect reveals that the friction factor increase with the enhancement of nanoparticle concentration.It is also observed that,plate velocity decreases the skin-friction but increases the wall heat transfer for both suction and blowing cases.The results indicate that the current research has a strong agreement with the relevant data in a limiting approach.