Bitumen Melting Inside a Tank, CFD Simulation ANSYS Fluent Training

Description

Bitumen Melting Description

The present simulation is about bitumen melting inside a bitumen tank via ANSYS Fluent. Bitumen is a material that increases in concentration when exposed to cold. In other words, the cold gradually causes the bitumen to freeze inside the tank.

Therefore, hot water flow pipes are used inside these tanks to upper the bitumen temperature inside the tanks and thus prevent it from freezing. In this project, a 2D bitumen tank is designed with periodic conditions.

Inside the tank, several rows of hot water pipes are designed. The bitumen material enters the tank at a low temperature, and its temperature increases when it receives heat from the pipe wall. This simulation uses a solidification and melting model to define phase change materials.

To define bitumen as a phase change material, the maximum temperature at which the solid phase temperature prevails (solidus temperature) is 340.15 K, the minimum temperature at which the liquid phase dominates (liquidus temperature) is 341.15 K, and the latent heat of pure solvent melting heat is defined as 450367 j.kg^-1.

Bitumen flow enters the tank with a speed of 0.1 m.s^-1 and a temperature of 343.15 K, and contacts the wall of hot water pipes with a constant temperature of 523.15 K.

Geometry & Mesh

The present geometry is designed in a 2D model via Design Modeler. The computational zone is the interior of a tank with several rows of pipes. This geometry is designed as a 2D plane with periodic conditions and can turn into a 3D cylindrical tank when checking the results.

 

The mesh of the present model has been done via ANSYS Meshing. Mesh is structured, and the number of production cells equals 10541.

Set-up & Solution

Assumptions used in this simulation:

• Pressure-based solver is used.
• The present simulation is unsteady.
• The effect of gravity is ignored.

 

Models
Viscous		k-epsilon
	k-epsilon model	RNG
	Near-wall treatment	standard wall function
Solidification & Melting Model		On
Energy		On
Boundary conditions
Inlet		Velocity Inlet
	velocity magnitude	0.1 m.s-1
	temperature	343.15 K
Inner Wall		Wall
	wall motion	stationary wall
	thermal condition	coupled
Outer Wall		Wall
	wall motion	stationary wall
	heat flux	0 W.m-2
Tubes’ Wall		Wall
	wall motion	stationary wall
	temperature	523.15 K
Outlet		Pressure Outlet
	gauge pressure	0 pascal
Methods
Pressure-Velocity Coupling		Coupled
	pressure	second-order
	momentum	first-order upwind
	energy	first-order upwind
	turbulent kinetic energy	first-order upwind
	turbulent dissipation rate	first-order upwind
Initialization
Initialization methods		Standard
	gauge pressure	0 pascal
	velocity (axial & radial)	0 m.s-1
	temperature	293.15 K

Bitumen Melting Results

After calculation, 2D and 3D contours related to temperature, temperature gradient, pressure, velocity, liquid fraction, and liquid fraction gradient are obtained. The contours show that in the vicinity of the hot pipes, the bitumen rises in temperature. An increase in temperature causes the bitumen to begin to melt. As a result, it prevents the bitumen from freezing.

You can obtain Geometry & Mesh file and a comprehensive Training Movie that presents how to solve the problem and extract all desired results.