Pardon me if this post is misplaced but it does not deal with electronics, but my problem is one of practical physics and perhaps someone has solved this issue.

I have fish. I keep them in a tank. Adding air and allowing it to bubble thru the water not only keeps the water oxygenated but it is pretty.

When I first established the tank I added some bubble strips against the back wall and found the effect pleasant. That lasted a few years till these inevitably wore out. I have yet to find anything that works as well. I've literally spent over $100 buying different types and pieces and nothing works consistently. The segments you join together will either emit a ton of bubbles or none as they are inconstant between pieces (I need 4). The single rubber tube types are also poor as they blast out all the air over a short segment and nothing in other areas.

If anyone has a working commercial solution for a consistent 48 inch wall of bubbles I would appreciate hearing it.

In lieu of a commercial solution I was thinking of using a length of PVC pipe, cap the ends, insert a nipple for the air line, and drill a series of holes to allow the air to bubble out. Uniformly spaced holes could produce uniform bubbles, but would anyone have any idea about the hole size?

 

Hole size depends on size of bubble and the pressure of the pump..! No ?
You could try different hole size and check which suites you.
And it would be better if you can pump air from both ends. Pumping from one end could lead to un-even bubbles

 

Pardon me if this post is misplaced but it does not deal with electronics, but my problem is one of practical physics and perhaps someone has solved this issue.

I have fish. I keep them in a tank. Adding air and allowing it to bubble thru the water not only keeps the water oxygenated but it is pretty.

When I first established the tank I added some bubble strips against the back wall and found the effect pleasant. That lasted a few years till these inevitably wore out. I have yet to find anything that works as well. I've literally spent over $100 buying different types and pieces and nothing works consistently. The segments you join together will either emit a ton of bubbles or none as they are inconstant between pieces (I need 4). The single rubber tube types are also poor as they blast out all the air over a short segment and nothing in other areas.

If anyone has a working commercial solution for a consistent 48 inch wall of bubbles I would appreciate hearing it.

In lieu of a commercial solution I was thinking of using a length of PVC pipe, cap the ends, insert a nipple for the air line, and drill a series of holes to allow the air to bubble out. Uniformly spaced holes could produce uniform bubbles, but would anyone have any idea about the hole size?

This is a chemical engineering problem. Those guys should be able to tell you the pressure drop along a piece of pipe if there are evenly spaced holes in it with back pressure being the depth of water. Viscosity of the gas, diameter of the microholes and thickness of tube wall will all play a role. You will never get perfect distribution but some small distribution will be possible with small enough holes.

 

This is a chemical engineering problem.

Sounds like mechanical engineering to me since no chemical reactions are taking place.

 

Equipment required: air pump, tube and tubing of compatible materials, various drill bits.

Procedure: experiment till it works.

 

Sounds like mechanical engineering to me since no chemical reactions are taking place.

Nope, @GopherT is right, flow through a pipe - or an orifice - is a classic chemical engineering subject. Basically anything that involves a flow of mass or energy is within the purview of Chem Eng. Reactions are just a complicating factor in the mass and energy balances.

You want to configure things so that the pressure drop ∆P across each orifice is much larger than any small dynamic ∆P across the header. This ensures that bubble size will depend on your supply pressure and orifice size - both under your control - as much as possible. I think it will be useful to think about the total cross-sectional area of all your pinholes relative to the diameter of the header.

That said, I don't see any easy way to determine the ideal orifice size without testing. The right diameter will depend on your aesthetic preferences, the ∆P available for a given total airflow (this depends on your pump performance), the wall thickness of the header, and probably even the material the header is made from.

My gut says you should choose a tubing that looks nice (clear acrylic?) and has at least about 1/4" ID for airflow. The pinholes will be really small I think, maybe 1/64" or less? Just guesses. I'm mentally picturing how much air can escape through a tiny hole in a bicycle innertube. A lot!

 

Sounds like mechanical engineering to me since no chemical reactions are taking place.

A common misconception. Chemical engineers have all the data on flowing fluids through pipes. An ME will help specify the pipe strength for pressure, support spans and thermal expansion.

 

Nope, @GopherT is right, flow through a pipe - or an orifice - is a classic chemical engineering subject. Basically anything that involves a flow of mass or energy is within the purview of Chem Eng. Reactions are jusa complicating factor in the mass and energy balances.

From everything I can find online related to fluid mechanics/dynamics every major reference to the study and practical application of fluid mechanics says mechanical engineering works with its application more than any other one.

https://www.google.com/search?q=wha...ome..69i57.16480j0j7&sourceid=chrome&ie=UTF-8

https://en.wikipedia.org/wiki/Fluid_mechanics

It's the engineering field I have always associated it with the most and even in my college classwork from years ago fluid mechanics was part of the mechanical engineering related classwork, not the chemistry classes.

So although chemical engineering may use it, mechanical engineering uses and is largely associated with it more.

 

So although chemical engineering may use it, mechanical engineering uses and is largely associated with it more.

Like motors are the overlap between electrical engineering and mechanical engineering, fluid mechanics is the overlap of mechanical engineering and chemical engineering.

Associated with it more? I think you need to learn more about chemical engineering. Most hated their "chemistry classes" and want to dissociate themselves as much as possible from chemistry - pumping fluids and calculating heat transfer and mass flow is not something a chemist does... Much.

your need to compartmentalize and argue with experts is funny.

 

your need to compartmentalize and argue with experts is funny.

I was not aware that going by most common applications of and association with in the general fields of engineering was compartmentalizing.

I mean, that is why engineering has multiple different fields right? So they can differentiate which one deals with what topics and concepts more than any other?

As for experts I have no clue who is an expert on line until either they have proven their expertise or at least above average knowledge and experience.

What I do know is that by far when it comes to online personas too many claim expertise on subjects yet when called to step up and deliver on what should be second nature knowledge, concepts and common processes of their supposed field of expertise they totally fail to show they are anything more than sheltered blustering fools trying to carry a fake persona as an expert.

Which means when I have doubts to someone claims I tend question them, when by my knowledge and experiences right or wrong, don't see their claim as being correct. Especially so when common definitions tend to favor my views.

 

I don't know what it takes to qualify as an expert, but 30 years as a professional (bio)chemical engineer should come close.

 

A common misconception. Chemical engineers have all the data on flowing fluids through pipes. An ME will help specify the pipe strength for pressure, support spans and thermal expansion.

You have the resources. Get you company started on the research of this very important project. Just say Ernie needs it for his fish tank. They will invest billions. If that does not work a little fraud on your part to get the project trough might be required. Ten to twenty years in federal prison won't be too bad. And Ernie will have his even sized bubbles.
. Help a brother out.

 

I don't know what it takes to qualify as an expert, but 30 years as a professional (bio)chemical engineer should come close.

Depends on what area and aspects of chemistry they focused on.

A industrial power systems Electrical Engineer and a digital circuit design Electrical Engineer are both EE's by name and trade but that doesn't mean either is an interchangeable expert on the others area of the field or daily actions and operations of employment.

I have no issue with interdisciplinary/crossover aspects of terminology or use but ultimately everything does have a primary and a secondary association with where it is used and in my books and according to general internet reference fluid mechanics/dynamics is most equated with mechanical engineering even if chemical engineering also relies on it a fair amount just the same as in certain areas of mechanical, civil and other engineering fields multiple sub disciplines and aspects of chemistry is used.

 

I don't know what it takes to qualify as an expert, but 30 years as a professional (bio)chemical engineer should come close.

You've referred to it dozens (if not hundreds) of times in conversations from air conditioners to pipes to various process/flow and heat transfer threads. I guess his lack of memory is, well, incurable.

 

Depends on what area and aspects of chemistry they focused on.

A industrial power systems Electrical Engineer and a digital circuit design Electrical Engineer are both EE's by name and trade but that doesn't mean either is an interchangeable expert on the others area of the field or daily actions and operations of employment.

I have no issue with interdisciplinary/crossover aspects of terminology or use but ultimately everything does have a primary and a secondary association with where it is used and in my books and according to general internet reference fluid mechanics/dynamics is most equated with mechanical engineering even if chemical engineering also relies on it a fair amount just the same as in certain areas of mechanical, civil and other engineering fields multiple sub disciplines and aspects of chemistry is used.

Chem engineering is applied fluid dynamics, mass/flow calculations, and heat transfer.

Justify all you want after that. It is now entertaining.

 

You've referred to it dozens (if not hundreds) of times in conversations from air conditioners to pipes to various process/flow and heat transfer threads. I guess his lack of memory is, well, incurable.

Prove my memory wrong and show me no less than 5 recent examples in any threads I have participated in where he has made such claims and I obviously would have read them.

Just because someone has said a lot in one place doesn't mean someone else has read it let alone has any knowledge of it whatsoever.

I for one have no knowledge of Wayneh being an chemical engineer of any sort. Maybe you know but since he and his posts are largely outside of my circles I have no such knowledge any more than you have any understandings of my extended knowledge base given any subjects I have ever posted on any other forums I frequent.

 

Chem engineering is applied fluid dynamics, mass/flow calculations, and heat transfer.

YesI have never claimed otherwise. I am simply going by the subject of the OPS question which pertains to making bubbles in a fish tank with compressed air source and some tubing which in that context has nothing to do with chemistry and in most technical views is a physics IE mechanical engineering subject. Now had he commented about possible PH compatibility of water salinity or any chemical aspect concerns with the system I would agree that it's a chemical engineering related subject but he did not so I have to take it as being a purely physical design concern.

Justify all you want after that. It is now entertaining.

Yes, I know your inability to gather proper context from simple subjects and then turn misunderstandings based on them into a pointless debates about largely irrelevant topics only you derived fro m your own inability to understand things is a great source of entertainment for you. No one's ever denied it.

In fact, you have demonstrated it so many times in so many threads it has thus given you the near undisputed expert status in using ignorance and general simpleton level illiteracy to misunderstand the obvious over most everyone on the forum except for maybe ronv and shortbus.

 

So, you really, really, smart people, how is he to create the bubbles he wants?

Damn, why do I feel like I'm I kindergarten?

 

So, you really, really, smart people, how is he to create the bubbles he wants?

Damn, why do I feel like I'm I kindergarten?

I think he pretty much has the basic concept figured out right from the get go. A tube with proper sized holes in it.

In lieu of a commercial solution I was thinking of using a length of PVC pipe, cap the ends, insert a nipple for the air line, and drill a series of holes to allow the air to bubble out. Uniformly spaced holes could produce uniform bubbles, but would anyone have any idea about the hole size?

Given The wall of bubbles requirement that is going to require both very small and constant bubble size which unfortunately for a fish tank is going to require being able to produce very tiny bubbles.

My theory would be to use the PVC or a similar semi rigid plastic pipe he mentions and drill holes in it with a micro drill bit, somethign like these but maybe even smaller,
https://www.amazon.com/Versatile-Tu...&sr=8-2-spons&keywords=micro+drill+bits&psc=1
being the smaller the holes the more uniform the air flow and release from hole to hole will stay in the tube.

As easy as it may sound drilling micro holes, even in plastic, without a proper drilling system is rather difficult given their extreme fragility.

As for actual drill size only he can determine that from the original bubble strips he had assuming any hole any of them can be measured with any degree of accuracy.

 

In order to ensure even dispersion of bubbles I would seek to eliminate any pressure gradient inside the pipe. This would require a pipe of sufficient diameter to make pressure drop across the length of pipe negligible.

For example if I had a 1/4" line going to my bubble pipe, spitballing, I would use probably a 1.5" PVC pipe with holes drilled in it and capped on both ends. I would run the air line to the center of the pipe, not one of the ends, for good measure. I would expect that to work nicely.

Granted this comes from a person lacking classical education in fluid dynamics. I have only a real-world, practical understanding of the topic, not even strong enough to assert whether it should be filed under chemical or mechanical engineering. That being said, I'm pretty sure I'm barking up the correct tree.