CFD, applications, governing equations, model of flow

 Computational fluid dynamics

•CFD is a branch of fluid mechanics that uses a numerical analysis and data structure to analyse and solve problems that involves fluid flows

•computers are used to perform the calculation and interaction of the fluid with surface define by boundary condition

•high speed supercomputers gives better results.

• CFD is applied to research and development problem including-*aerodynamics*Aerospace*weather simulation*industrial system design and analysis*heat transfer & engine and combustion analysis.

Modeling in CFD software 

•cfd provides understanding on the physics of a flow system

•the governing equations and fundamental principles upon which CFD codes are based discribe followed

#governing equations

•mathematical formulation of conservation laws of fluid mechanics

•conservation laws relate the rart of change of

a desired fluid property to external forces and can be considered as a -

#conservation of mass ( continuity)

#conservation of momentum ( Newtown 2nd laws )

#conservation of energy ( 1st law of thermodynamics)

Turbulence modeling 

•turbulance is a state of flow characterized

By chaotic , tangled fluid motion

•it's an inherently unsteady phenomenon

•the navier stokes equation can be used to predict turbulent flow but__

•the time & space scales of turbulence are very tiny at compared to the flow domain

•scale of smaller turbulent Eddie's are about a thousand times smaller than the scale of the flow domain.

•solving unsteady flows with large no. Of grid points is a time consuming tank 

•time average the navier  stokes equation to remove the high frequency unsteady component of the turbulent fluid motion

•model the "extra" terms resulting from the time average process using empirically based turbulence modes 

#non Newtonian fluid modeling 

•Any fluid that doesn't obey the Newtonian relationship between shear stress & shear rate is called non Newtonian fluid.

•CFD provide better understanding of the mixing , heating , cooling & transport process of non-Newtonian substances

Application of CFD in food industry 

A] food production facilities

•cfd used to airflow & ventilation design

B] cold storage facilities

•cfd used to predicting environment variable within ventilated packaging & Refrigerated store room 

•cold storage process simulated in a CFD model 

C] household & industrial Refrigeration

•cfd modeling used to develop a new air supply system

D]Sterilization 

•used to show temperature history and survival spores 

E] stirred thanks 

•to flow rate & suitable impeller rheometry 

CFD are used 

F] drying- CFD are used to uniformity of air flow in drying system