Bazooka-ish Creation

[rosej3570]

I got a CFD analysis started on the Bazooka-ish Gold Trap. I did 3/32" holes, spaced 1/4" apart, one set down, the next at 45 degrees to the sides, then down again. I ran a lot of simulations and only had a couple vortex's begin. I will run more analysis when I have time. I also have a video, but I have to figure out how to upload it. I wonder if putting in a wedge on the bottom of the bed may help drive vortex's to catch finer gold. I will try it sometime and see.

 

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[arizau]

Just a few random thoughts based on what I understand about how fluid beds of a general sort work. I don't think their optimum is to have a vortex but to have as even an upward pressure (active uplift) when measured at any point just below the natural surface area. That is achieved by having a single central source of fluid introduction from the bottom of the container. The bazooka has some dead areas that have little to no uplift and that may be good since it allows particles to first sink, get stirred and then settle and stay by some combination of weight, shape and density. By the same token it may benefit with a more equal distribution of upward pressure where there is a straight shot to the surface. Maybe that is the reason that all the holes are angled outward in a bazooka.

Good luck on your design.

 

[rosej3570]

Arizau,
I have been trying to figure out if a vortex is better or particle separation from the upward pressure. I don't know how the holes on the Bazooka are, I thought I had read that they shot down at a slight angle. My concern if they are more horizontal, is that about half of the trap is being under utilized, because light and heavy particles are not being put in motion for the lights to get washed away. Obviously, the Bazooka works as it was designed. I am hoping to put a little more analysis to it. I was happy to get the CFD to work this far.

I did toy with the idea of making a flat plate with holes in it instead of having the tubes, more like a real fluidized bed. I may try that when I have time.

Thank you for your input.

 

[arizau]

When I said "angled outward" I didn't mean horizontal but more like at 45 degrees to each side. You mentioned that you also have some holes aimed straight down. I think Goodguy uses that pattern but Bazooka Gold Company did not. I have thought about ways to have the flow even and straight up for the full area and all of them lead to plugging or difficulty at cleanup time when the flow is cut off. Maybe you can figure something out that doesn't.

Good luck.

 

[Au dave]

On my diy zook hole spacing is 1/2" x 2 rows per tube at 4:30 and 7:30 o'clock.If you are using 3 tubes make sure the centre tube holes are offset to the other tubes so the jets don't clash. I did have a row of holes at 6:00 o'clock but found that this caused the trap to scour out, hole size is 1/8".

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[rosej3570]

Arizau and au Dave, thank you for you information. I'm going get 5 or so tube hole ideas to simulate to look at differences and if there is an optimum configuration. Here is the present configuration. The 45 degree from center holes are 1/2" apart, but there are holes straight down in between those.

I'll run one with no straight down holes.

One thing that would be useful is what the flow rate of a stream is. If I have a low, medium, and high number I could try all three to see if that changes the simulation.

 

[rosej3570]

Another CFD Analysis. Details are in the description of the video.

 

[Goodyguy]

Arizau and au Dave, thank you for you information. I'm going get 5 or so tube hole ideas to simulate to look at differences and if there is an optimum configuration. Here is the present configuration. The 45 degree from center holes are 1/2" apart, but there are holes straight down in between those.

I'll run one with no straight down holes.

One thing that would be useful is what the flow rate of a stream is. If I have a low, medium, and high number I could try all three to see if that changes the simulation.

View attachment 1447618

The goal is to achieve consistent fluidization throughout the trap when the trap is full of material. Keep in mind that the material will be denser toward the bottom of the trap and lighter toward the top.

Scouring is usually due to too fast of a flow down the deck into the trap or else the sluice set at too steep of an angle. Keep in mind also that Larger holes = slower flow, smaller holes = faster flow through the jets. The same goes for number of holes. More holes = slower flow.

The flow into the scoop that feeds the fluidizing tubes needs to be taken into account when calculating the number of jets as well as hole size for a particular size trap.
Seems complicated, but a happy medium works best considering that every stream will have a different speed flow. Even the same stream on different days the flow will vary.



Go for the Gold
GG~

* simulations are a useful tool when all the the variables are factored in.
But it's hard to beat field testing to realize all the variables to factor.

 

[rosej3570]

The goal is to achieve consistent fluidization throughout the trap when the trap is full of material. Keep in mind that the material will be denser toward the bottom of the trap and lighter toward the top.

Scouring is usually due to too fast of a flow down the deck into the trap or else the sluice set at too steep of an angle. Keep in mind also that Larger holes = slower flow, smaller holes = faster flow through the jets. The same goes for number of holes. More holes = slower flow.

The flow into the scoop that feeds the fluidizing tubes needs to be taken into account when calculating the number of jets as well as hole size for a particular size trap.
Seems complicated, but a happy medium works best considering that every stream will have a different speed flow. Even the same stream on different days the flow will vary.



Go for the Gold
GG~

* simulations are a useful tool when all the the variables are factored in.
But it's hard to beat field testing to realize all the variables to factor.

Goodyguy, this is fun, I don't have a stream to run to quick, so the CFD is giving me something to keep my mind active and hold my attention for a bit. I keep running into all the variables. I found one video that claims to show how the fluidized bed works with gold, but it didn't take into account the stream water coming over the slick plate. That is what my last video shows, bit the opening is very small.

I just ran an analysis with 3/4" opening from the slick plate and an exit. Totally different flow of material. A lot of the material flows on top of the trap, in then out. This may not be a problem if the heavies are falling out in the trap. Almost more of a reason to have a lot g slick plate, and maybe longer trap.

I'll keep playing and with the CFD and then do real testing. I did move the tubes higher and lower and it seemed 3/4" center point off the bottom was good. Variable angled holes could do a lot too.

 

[goldog]

Did you add a diverter in the trap? Something to push the material down. Bazooka uses a 1/4" bar along the underside of the upper deck.

 

[rosej3570]

Goldog, no I didn't. I have never seen one in person so I am going off what seems to work. I was thinking that a sluice bar under that top plate would help force the flow down. Based on what you said I will try it with the CFD. Even a slightly angled bar will divert the flow to the trap, which will help get all material to be worked in the fluidized bed.

 

[Goodyguy]

Goodyguy, this is fun, I don't have a stream to run to quick, so the CFD is giving me something to keep my mind active and hold my attention for a bit. I keep running into all the variables. I found one video that claims to show how the fluidized bed works with gold, but it didn't take into account the stream water coming over the slick plate. That is what my last video shows, bit the opening is very small.

I just ran an analysis with 3/4" opening from the slick plate and an exit. Totally different flow of material. A lot of the material flows on top of the trap, in then out. This may not be a problem if the heavies are falling out in the trap. Almost more of a reason to have a lot g slick plate, and maybe longer trap.

I'll keep playing and with the CFD and then do real testing. I did move the tubes higher and lower and it seemed 3/4" center point off the bottom was good. Variable angled holes could do a lot too.

A longer trap will help give the gold more time to drop out of the flow, especially the flat flakes that want to surf. That's why I use a damper flap positioned just inside the trap to slow down the incoming material and to insure that everything gets dunked.

Going to experiment with using a magnetic bar attached across the underside of the front of the trap cover that will act as a gold brake and once its covered with magnetic sand it will also act as a diverter baffle.


GG~

 

[rosej3570]

Here are two more CFD Analysis. This time with the full model. The tubes are 15 degrees off vertical, staggering left/right every .2 inches. One of them has a 1/4" diverter bar under the top rock plate.

I wanted to put both in one video side by side, but this video stuff is new to me. I am using Blender for the video editing, so there is a bit of a learning curve.

 

[Goodyguy]

Here are two more CFD Analysis. This time with the full model. The tubes are 15 degrees off vertical, staggering left/right every .2 inches. One of them has a 1/4" diverter bar under the top rock plate.

I wanted to put both in one video side by side, but this video stuff is new to me. I am using Blender for the video editing, so there is a bit of a learning curve.

Cool videos