CFDSOF Practices

CFDSOF Practices

Hi, it’s me again, now I’m gonna share about my practice using CFDSOF which developed by a team led by my lecturer Mr. Dr. Ir. Ahmad Indra Siswantara. These are some cases which I use for practice.

1. Fuel Rod

Fuel rod is a long tube, often made of a zirconium alloy and containing uranium-oxide pellets, that is stacked in bundles of about 200 to provide the fuel in certain types of nuclear reactor. The fuel rods in a nuclear reactor, whether they are cylindrical or flat plates, are designed with two purposes. The first is to seal in the nuclear fuel. Nuclear fuel, when it is used in the reactor, becomes contaminated with highly radioactive fission fragments. The presence of the leftovers presents an extreme hazard because of the radioactivity, and it is quite long-lived. When the fuel is spent, we can remove the fuel bundle (during refueling) knowing the radioactive material inside will stay sealed, stay contained, welded tight within the fuel rod. The other function of the fuel rods is to set up the geometry of a reactor. Let’s look at that.

The thing that actually starts any nuclear chain reaction is a spontaneous fission event that releases neutrons. The neutrons initiate and build the chain (and are better at doing that if they slow down). But only if there is enough fissionable material nearby to set up a critical mass. Critical mass in a nuclear weapon is achieved by slamming sub-critical chunks of fissionable material together. In a nuclear reactor, control rods, which absorb neutrons, are pulled out, and at some point there isn’t enough neutron-absorbing material in the core to stop the reaction. It begins. The fuel rods, because of their size and shape, contribute to the engineering solution of laying out the core (which is composed of fuel bundles) so that it will go critical when the rods are extracted a certain amount. The spacing is also set up to allow primary coolant to move throughout the core and remove the heat effectively as it acts to slow down the neutrons which will continue the chain.

By using CFDSOF I’m gonna try to simulate the phenomenon which is happened when a fuel rod works. The first step is building the grid (building grid tutorial can be seen in my another post, here is the link :                              )

The grid that I made for fuel rod is like this (picture below)

Fuel rod - grid

After that, try to simulate some properties and phenomenon which happened when a fuel rod works, such as:

a. Temperature

Fuel Rod - temperature

From the image we could see the temperature of fuel rod, which is the highest temperature located in the center of cylinder

b. Absolute Pressure

Fuel Rod - abstot pressure

c. Velocity Magnitude Vector

Fuel rod - velocity magnitude vector

d. Velocity Magnitude

Fuel Rod - velocity mag

2. Converging/Diverging Nozzle

The next case is about converging/diverging nozzle.

A converging-diverging nozzle is an important tool in aerodynamics. Also called a de Laval nozzle, it is an essential element of a supersonic wind tunnel. In this application the nozzle draws air from a reservoir which is at atmospheric conditions or contains compressed air. Back pressure at the end of the diverging section is such that air reaches sonic conditions at throat. This flow is then led through the diverging section. As we have seen before the flow Mach Number increases in this section. Area ratio and the back pressure are such that required Mach Number is obtained at the end of the diverging section, where the test section is located. Different area ratios give different Mach Numbers.

We study here the effect of Back Pressure on the flow through a given converging-diverging nozzle. The flow is somewhat more complicated than that for a converging nozzle. Flow configurations for various back pressures and the corresponding pressure and Mach Number distributions.

The first step is building grid in CFDSOF, which is shown by picture below

convdiv noozle

After that, try to simulate some properties and phenomenon which happened when a converging diverging nozzle works, such as:

a. Mach Number

mach number

Mach number equals object speed divided by speed of sound

b. Absolute Pressure

Covdiv nozzle press

c. Density

Densitas convdiv nozzle

3. Cyclone Separator

The principle of working from cyclone separator is a high speed rotating (air)flow is established within a cylindrical or conical container called a cyclone. Air flows in a spiral pattern, beginning at the top (wide end) of the cyclone and ending at the bottom (narrow) end before exiting the cyclone in a straight stream through the center of the cyclone and out the top. Larger (denser) particles in the rotating stream have too much inertia to follow the tight curve of the stream and strike the outside wall, falling then to the bottom of the cyclone where they can be removed. In a conical system, as the rotating flow moves towards the narrow end of the cyclone the rotational radius of the stream is reduced, separating smaller and smaller particles.

This is the simulation result using CFDSOF

a. X-Z Section

Penampang x-z

b. Absolute Total Pressure

Abs Total Pressure

c. Velocity

w separator

d. Turbulence

Turbulence separator

Thank you 🙂


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