Study of transport phenomenon in Carreau fluid using Cattaneo–Christov heat flux model with temperature dependent diffusion coefficients

This paper studies the heat transfer mechanism in deep grinding process, especially the heat flux to the workpiece. On the basis of triangle moving heat source, a quadratic curve heat flux model in the grinding zone was developed to determine the heat flux distribution and to estimate the surface temperature of workpiece. From the calculated theoretical expression of heat flux to the workpiece, the quadratic curve heat flux can be understood as the superposition of square law heat flux, triangular heat flux and uniform heat flux in the grinding zone. Then four heat flux models using the determined amount of heat flux were applied to estimate the workpiece surface temperatures which were compared with that measured by the embedded thermocouple. It has been found that the quadratic curve heat flux distribution seems to give the best match with measured and theoretical temperature, although square law heat flux model is good enough to predict the temperature.

Download Full-text

A Model for Droplet Vaporization for Use in Gasoline and HCCI Engine Applications

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.1688367 ◽

2004 ◽

Vol 126 (2) ◽

pp. 422-428 ◽

Cited By ~ 10

Author(s):

Youngchul Ra ◽

Rolf D. Feitz

Keyword(s):

Heat Flux ◽

Internal Heat ◽

Droplet Surface ◽

Fuel Vapor ◽

Gas Mixture ◽

Ambient Temperatures ◽

Droplet Vaporization ◽

Flux Model ◽

Heat Flux Model

A model for unsteady droplet vaporization is presented that considers the droplet temperature range from flash-boiling conditions to normal evaporation. The theory of continuous thermodynamics was used to model the properties and compositions of multicomponent fuels such as gasoline. In order to model the change of evaporation rate from normal to boiling conditions more realistically, an unsteady internal heat flux model and a new model for the determination of the droplet surface temperature is proposed. An explicit form of the equation to determine the heat flux from the surrounding gas mixture to the droplet-gas interface was obtained from an approximate solution of the quasi-steady energy equation for the surrounding gas mixture, with the inter-diffusion of fuel vapor and the surrounding gas taken into account. The model was applied to calculate evaporation processes of droplets for various ambient temperatures and droplet temperatures.

Download Full-text

Numerical study of Carreau nanofluid flow past vertical plate with the Cattaneo–Christov heat flux model

International Journal of Numerical Methods for Heat &amp Fluid Flow ◽

10.1108/hff-03-2018-0104 ◽

2019 ◽

Vol 29 (2) ◽

pp. 702-723 ◽

Cited By ~ 6

Author(s):

Vasu B. ◽

Atul Kumar Ray

Keyword(s):

Heat Flux ◽

Brownian Motion ◽

Weissenberg Number ◽

Motion Parameter ◽

Conduction Model ◽

Content Type ◽

Carreau Nanofluid ◽

Flux Model ◽

Heat Flux Model ◽

Brownian Motion Parameter

PurposeTo achieve material-invariant formulation for heat transfer of Carreau nanofluid, the effect of Cattaneo–Christov heat flux is studied on a natural convective flow of Carreau nanofluid past a vertical plate with the periodic variations of surface temperature and the concentration of species. Buongiorno model is considered for nanofluid transport, which includes the relative slip mechanisms, Brownian motion and thermophoresis.Design/methodology/approachThe governing equations are non-dimensionalized using suitable transformations, further reduced to non-similar form using stream function formulation and solved by local non-similarity method with homotopy analysis method. The numerical computations are validated and verified by comparing with earlier published results and are found to be in good agreement.FindingsThe effects of varying the physical parameters such as Prandtl number, Schmidt number, Weissenberg number, thermophoresis parameter, Brownian motion parameter and buoyancy ratio parameter on velocity, temperature and species concentration are discussed and presented through graphs. The results explored that the velocity of shear thinning fluid is raised by increasing the Weissenberg number, while contrary response is seen for the shear thickening fluid. It is also found that heat transfer in Cattaneo–Christov heat conduction model is less than that in Fourier’s heat conduction model. Furthermore, the temperature and thermal boundary layer thickness expand with the increase in thermophoresis and Brownian motion parameter, whereas nanoparticle volume fraction increases with increase in thermophoresis parameter, but reverse trend is observed with increase in Brownian motion parameter.Originality/valueThe present investigation is relatively original as very little research has been reported on Carreau nanofluids under the effect of Cattaneo–Christov heat flux model.

Download Full-text