Landracing Forum
Tech Information => Technical Discussion => Topic started by: Paul P on February 05, 2019, 09:45:07 AM
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I need to build a 20 gallon coolant tank for my Bonneville car. I didn't find any specific rules regarding coolant tanks other than you cannot use flammable coolant (like Evans). I want to mount it behind the driver seat (what would have been the floorboard of the rear seats). Any problems with this location according to the tech inspectors? I am thinking of using 6061 aluminum for the tank. What thickness would you recommend? What are the best hoses to use ? I already have 2 AN20 bulkhead connectors that pass though the firewall that was previously used for a dry sump system that I intend to re-purpose for the coolant. I know some are using a radiator in a box but I am trying to keep it simple. I don't want to build it then hit a snag in inspection. I have a TIG welder that will do aluminum or steel.
Paul
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My roadster has an aluminum tank. Much smaller than 20 Gal. What are you building?
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You might consider isolating the hot water tank from you.... being doused with 160-210 degree water will ruin your day.
Think about what might happen if you blow a head gasket and get compression pressure in your tank. Your cap pressure relief may not let pressure out fast enough to prevent a tank failure.... consider that when building your tank... rounded corners, internal braces...
Good luck with your project. :cheers:
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We have a 25 gal aluminum water tank right behind the drivers seat. It was an easy way to get 200 lbs of ballast over the rear axle for dual purpose. Our tank is not pressurized as we use an electric water pump and have a large overflow coming from the top of the tank exiting out the bottom of the car.
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My water tank is located behind the driver we built it using aluminum .060 thick capacity is 17 gallons I placed the firewall in front of the tank so if any leaks develop no hot water is getting on the driver I also do not run pressure in the tank I found out long ago any shape other than round will not hold pressure without bulging and bursting.
Ronnieroadster
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We have a 10 gal. compressed air tank mounted in the front of our rear engine lakester. .090 Aluminum bulkhead between tank and driver. Had to weld tube between top rear and bottom front of tank for steering shaft to pass through.
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keep in mind the "SLOSH" of the chute hit---baffles and edges reinforced---also twist and flex of frame loading and unloading as well as jacking
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My roadster has an aluminum tank. Much smaller than 20 Gal. What are you building?
It's already built. 1976 Monza running a turbo charged F motor. The reason I am adding the tank is to offset the horsepower increase I am putting into the motor. Previous runs had the water temp at 220 when I hit the chute and shut it down. I am adding substantial power so I know that means more heat. I was comfortable with the 220 at shutdown but I'm sure it will be much higher with the added power so I want to build in a buffer.
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You might consider isolating the hot water tank from you.... being doused with 160-210 degree water will ruin your day.
Think about what might happen if you blow a head gasket and get compression pressure in your tank. Your cap pressure relief may not let pressure out fast enough to prevent a tank failure.... consider that when building your tank... rounded corners, internal braces...
Good luck with your project. :cheers:
Good advice. I had been thinking the same thing and was trying to figure out a way of adding extra relief valve volume. Preferably I would like to find someone who can roll the tank for me.
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We have a 25 gal aluminum water tank right behind the drivers seat. It was an easy way to get 200 lbs of ballast over the rear axle for dual purpose. Our tank is not pressurized as we use an electric water pump and have a large overflow coming from the top of the tank exiting out the bottom of the car.
If I am reading your post correctly you just let it blow out if it gets hot enough to boil. I had not thought of that approach but I like it the more I think about it. Thanks for the ideas.
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My water tank is located behind the driver we built it using aluminum .060 thick capacity is 17 gallons I placed the firewall in front of the tank so if any leaks develop no hot water is getting on the driver I also do not run pressure in the tank I found out long ago any shape other than round will not hold pressure without bulging and bursting.
Ronnieroadster
Dallas V also said he does not run pressure. I like that idea. Did you get your tank rolled? Who rolled it? I realize if you get a head gasket failure that square cornered tank will soon be round. So I like the idea of a round tank. It looks like some racers are just taking an air tank and modifying it for coolant.
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We have a 10 gal. compressed air tank mounted in the front of our rear engine lakester. .090 Aluminum bulkhead between tank and driver. Had to weld tube between top rear and bottom front of tank for steering shaft to pass through.
If I read it right, you modified a standard air tank for coolant? I thought about that because I can't find anyone to roll the plate for me. Is your tank aluminum or steel?
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keep in mind the "SLOSH" of the chute hit---baffles and edges reinforced---also twist and flex of frame loading and unloading as well as jacking
Good advice.
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We have a 25 gallon water tank in the rear and a water pump that pumps it around the motor. I ran to the 4 mile marker last year at 265mph in my blown fuel roadster and the water was just warm. We do not seal it but just pump it round. We leave a gap for expansion and we have a catch tank if it gets hit.
Make sure you are not close to the tank. If you get boiling water down your neck it is not a nice experience.
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The air tank ii a portable one and is steel. Came from Walmart several years ago for $39. Figured we couldn't make anything for that price. Added an inlet, outlet, vent, and drain.
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I find it interesting that so many guys do not run pressurized cooling systems, especially on blown or turbo engines. As we all know cooling system water pressure increases the water boiling point and is especially critical around exhaust valves. Duke and I run a round 10 gallon tank made from 3003 aluminum, with crowned tank ends and a 17 lb pressure cap never had a problem but we do run methanol which really keeps the engine cooler. At 20 psi the longitudinal and hoop stresses are approx. 1000 psi and 2000 psi respectively and the material yield strength is 10,000 psi for annealed condition. The end caps are domed and the weld joint is designed to be in tension so its load is less than 3000 psi which gives us a safety factor of over 3:1 on yield strength. Based on these numbers we feel confident to run a pressurized cooling system.
Rex
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I find it interesting that so many guys do not run pressurized cooling systems, especially on blown or turbo engines. As we all know cooling system water pressure increases the water boiling point and is especially critical around exhaust valves. Duke and I run a round 10 gallon tank made from 3003 aluminum, with crowned tank ends and a 17 lb pressure cap never had a problem but we do run methanol which really keeps the engine cooler. At 20 psi the longitudinal and hoop stresses are approx. 1000 psi and 2000 psi respectively and the material yield strength is 10,000 psi for annealed condition. The end caps are domed and the weld joint is designed to be in tension so its load is less than 3000 psi which gives us a safety factor of over 3:1 on yield strength. Based on these numbers we feel confident to run a pressurized cooling system.
Rex
Who rolled the aluminum for you? I would prefer a round tank but I am having trouble finding someone who can roll it.
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Where are you located Paul P.????
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Paul,
I cut a piece approx 38 x 20, divided the piece in the 20 inch direction approx 1 inch apart, 36 lines, and then used my tin break and incrementally bent along each line until the ends came together. I then put the largest radius wheel in my little english wheel and ran over each of the bends to make it a little more round. Made a quick buck from two pieces of plywood cut to 12 inch diameter with a piece of 4x4 between them and then a couple of ratchet tie downs around it to hold the ends together and tacked with the TIG welder, then had my son Duke, weld together. All welds except the final top to the tank are welded from both sides. Used one of the 12 inch dia plywood parts of the buck to make the end pieces, started with a piece of aluminum cut to about 13 inch dia, then rolled a slight dome with the english wheel and annealed the edges, routed a 1/2 inch radius on the 12 inch plywood and beat the edges of the aluminum over with a soft hammer. Messed around until I got a nice fit and Duke welded complete.
Rex
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We have an 18-gallon cubicle tank situated mainly over the right side of the rear end of our street roadster (offsetting the driver). It's not under pressure, but has a relief outlet to the back of the roadster. It's built of 1/8-inch steel with a 1/4-inch bottom. It's successfully cooled the car 5+ miles time after time. In fact, the same water is there after 15 years. Maximum temp recorded in the engine at Bonneville was about 190º. We've been choking it off with the gate valves to maybe get a few more horsepower at El Mirage.
Water, and its container, is cheap ballast. And, if you fill it up, it doesn't slosh around much.
Sometimes methinks some overthink all this (why not a refrigeration unit inside a radiator inside a tank, back 18% of the driver, controlled with a digital thermostat that allows a printable readout that we can put on Facebook?).
Stan Back
Holding Street Roadster Records for 17 Years with a Sledge Hammer
(Your Results May Vary)
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Where are you located Paul P.????
I am in Oklahoma City.
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We have an 18-gallon cubicle tank situated mainly over the right side of the rear end of our street roadster (offsetting the driver). It's not under pressure, but has a relief outlet to the back of the roadster. It's built of 1/8-inch steel with a 1/4-inch bottom. It's successfully cooled the car 5+ miles time after time. In fact, the same water is there after 15 years. Maximum temp recorded in the engine at Bonneville was about 190º. We've been choking it off with the gate valves to maybe get a few more horsepower at El Mirage.
Water, and its container, is cheap ballast. And, if you fill it up, it doesn't slosh around much.
Sometimes methinks some overthink all this (why not a refrigeration unit inside a radiator inside a tank, back 18% of the driver, controlled with a digital thermostat that allows a printable readout that we can put on Facebook?).
Stan Back
Holding Street Roadster Records for 17 Years with a Sledge Hammer
(Your Results May Vary)
That is the kind of feedback I needed. If yours works mine should do the job. I do have a tendency to overthink things but once I have thought it through I always want the simplest solution. Simple means less to go wrong. What size motor are you running?
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We have an 18-gallon cubicle tank situated mainly over the right side of the rear end of our street roadster (offsetting the driver). It's not under pressure, but has a relief outlet to the back of the roadster. It's built of 1/8-inch steel with a 1/4-inch bottom. It's successfully cooled the car 5+ miles time after time. In fact, the same water is there after 15 years. Maximum temp recorded in the engine at Bonneville was about 190º. We've been choking it off with the gate valves to maybe get a few more horsepower at El Mirage.
Water, and its container, is cheap ballast. And, if you fill it up, it doesn't slosh around much.
Sometimes methinks some overthink all this (why not a refrigeration unit inside a radiator inside a tank, back 18% of the driver, controlled with a digital thermostat that allows a printable readout that we can put on Facebook?).
Stan Back
Holding Street Roadster Records for 17 Years with a Sledge Hammer
(Your Results May Vary)
I had someone recommend using a fuel cell since I'm not going to run it under pressure. What do you think?
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Ref. replies #15 and #18
Rex, and other interested parties--
Working backwards from the data you stated, it appears your tank is 12” in diameter with 0.060” wall aluminum material. The photo doesn’t very well show the 1/2” radius mentioned at the joint of the cylinder and head, but I assumed it was there per your description. While the radius is much improved from a sharp corner, it doesn’t really constitute a spherical or elliptic tank head insofar as nicely accommodating stresses from internal pressure. Taking these dimensions, and assuming a 1/2” crown to the lid, an axisymmetric finite element model was made of the upper quadrant of the tank and was subjected to 20 psi internal pressure. As you can see from the jpeg’s attached (if I can do that correctly), Pd/2t isn’t the last word on the stress distribution of the vessel.
Given the number of commercially available pressure vessels of various sorts (air tanks, scuba tanks, beer kegs, gas transport tanks, etc., etc.) that are necessarily built to ASME or other criteria, it seems much easier and confidence inspiring to re-purpose such a thing as opposed to making one from scratch. Pressure vessels are trickier to do correctly than they might appear to be.
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I.O.
Thank you very much for the FEA on our water tank! Looks to me that we might need to add some additional material in the area of the radius. Another thing on the "to do" list!
As long as you have the model what would it look like if we added an aditional ring of .062 in the area of highest stress?
Thanks again!
Rex
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A reference from another build: http://www.landracing.com/forum/index.php/topic,8271.msg157683.html#msg157683
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I.O.
Thank you very much for the FEA on our water tank! Looks to me that we might need to add some additional material in the area of the radius. Another thing on the "to do" list!
As long as you have the model what would it look like if we added an aditional ring of .062 in the area of highest stress?
Thanks again!
Rex
Run a no pressure system and you eliminate the stress like many of us are doing just saying. :cheers:
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I run a non-pressurized rectangular (mostly) tank. It used to be the fuel tank. It has worked pretty well, but is rounder since I holed a piston.
Will Willis #6302
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I have run a fuel cell for cooling water for my radiator in a box and can tell you from first hand experience---you better have a VERY big vent if you ever start retuning steam to it--they blow up like a balloon and can definitely destroy body panels, which then can induce aero steer which may lead to an unexpected high speed exit of the track :-D
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Pucker factor then approaches infinity! :-o :-D :-P
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Ref. reply #24
Rex,
While it seems easy to add a reinforcing strip to the model, it actually involves incorporating special contact elements between the original and the strip, which can be somewhat tedious and tricky to work with. Besides, it is easy to say what the effect will be--the maximum stress will be marginally reduced and the location will move radially inward to where the ID of the strip winds up. I don’t see much point in doing that.
Obviously, the 38ksi peak result of the elastic solution is useful to show where and to what degree there may be structural concerns, but 38 ksi would never be generated there since the yield strength of the aluminum is around 10 ksi. The material would yield and larger local strains generated. The problem is that the endload of the closure is having to be carried by the thin material at the radius in bending, which quickly generates high stresses--as can be seen since the same endload is carried in tension in the cylindrical wall at a much lower stress level. To transfer the load into the cylinder without the bending, the closure needs to be much stiffer--added ribs across the end or a thicker, stiffer endplate. (However, a thick/stiff endplate would not expand radially as fast as the cylinder wall, leading again to bending of the cylinder wall at the junction, although probably less so than the existing arrangement). The tapered junction of a traditional elliptical tank head would also tend to transfer the load but with more compatible radial displacements.
As pressure is put into the tank as it stands, the stress at the radius would rise to the yield point, at which time the end cap would begin to permanently deform (balloon), changing the geometry, relieving the bending and moving toward a more tensioned stress state. The question is, as pressure increases, whether the structure would obtain a stable geometry before the material ruptures. (I may play around with an elastic/plastic analysis version of the existing model to see how it goes).
In any case, it would be prudent to do a proof test of the tank USING WATER to some pressure in excess of the service pressure before putting it into service. Doing this in stages and observing deflections and any “permanent” distortion may give an indication of whether it can be made to work successfully as presently constituted.
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Paul –
My solution was tested previously on a 250-MPH Monza. Worked there – every time. PM sent. Give me a reply and we can talk.
Stan
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Look at some of the large intercooler tanks they withstand a lot of boost and are not round. Some have added a strap
of metal overlapping along welds for reinforcement. We did expand and split welds on our rectangular tank when we torched thru the head into the water jacket and blew off water lines at engine. Not fun at 260+ when windshield fogged up. 2 chutes and 4 wheel brakes.
JL222
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After reading IO's info it got me to thinking about going to a "radiator in a box" system as I believe that it is important to have a pressurized cooling system. I dug through some of my stuff and I found a nice Harrison liquid/air heat exchanger that I have had for quite a while, years ago I put some -10 AN fitting on it and it is just the right size to fit into our existing 12 inch dia tank. Another thing to get done before Bonneville! but probably a good idea. If I do it this year I will post some pics.
Rex
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The FEA analysis was extended by considering the material to be bi-linear elastic-plastic.
Young’s modulus for the elastic portion of the stress-strain “curve” was 10.6e6 psi.
The plastic portion went from the 10,000 psi yield point of the elastic portion to a point at 18,000 psi and 0.25 strain as an approximation of a stress-strain curve since an actual curve for the material is unavailable.
The von Mises stresses and total strain results are shown in the plots below.
The large red potion of the stress plot shows that that area had plastically deformed beyond the 10 ksi yield point up to a maximum of 10,242 psi (which is a point on the plastic portion of the curve). The plot also shows that the end cap displaces a maximum of 0.188” axially, and that this displacement draws the radiused part at the corner radially inward.
The second plot shows the strain (or stretching) of the material with the maximum inside the radius and to the amount of 0.013. This amount of strain is just beyond the yield point and well short of the assumed .25 strain at the assumed ultimate tensile load of 18,000 psi.
Upon relaxing the pressure load, the plastic portion of the tank would go into a more compressive state of stress, and the elastic portion would also acquire an array of residual stresses--not back to its original “unstressed” situation. With a second pressure application the stresses would again return to substantially that of the original load.
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After reading IO's info it got me to thinking about going to a "radiator in a box" system as I believe that it is important to have a pressurized cooling system. I dug through some of my stuff and I found a nice Harrison liquid/air heat exchanger that I have had for quite a while, years ago I put some -10 AN fitting on it and it is just the right size to fit into our existing 12 inch dia tank. Another thing to get done before Bonneville! but probably a good idea. If I do it this year I will post some pics.
Rex
(http://purplesagetradingpost.com/sumner/Hooley%202013/rad-in-box-76.jpg)
Has worked well for us...
http://purplesagetradingpost.com/sumner/Hooley%202013/13%20-%20construction%20menu.html
... and believe in all the advantages you mentioned in having a pressurized system on the engine side,
Sumner
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Sumner... Happy Birthday my friend
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SS1 do you think Sum was trolling us for a happy birthday card?
Happy B'Day Sum!!!!!!!!!!!!!1 :cheers:
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SS1 do you think Sum was trolling us for a happy birthday card?
Happy B'Day Sum!!!!!!!!!!!!!1 :cheers:
Thanks guys, but not really 8-). The yard will put us in the water Wed. Hope the rebuilt transmission and old diesel are good to go. It has been a lot of work to go maybe 8 mph :cry:
Sumner
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How romantic Valentines day on the water :cheers: to you, Dottie and crew
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Sum... most of us do a lot of work to go a couple miles and hour faster.... I'm guessing your boat was a 6-7 KPH boat 8 would be 15% worse case increase... most of us would give our left nut for that number :roll:
Hope you had a great birthday... Stop by again sometime :cheers:
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If you do end up building a custom tank of aluminum, I strongly suggest a wall thickness substantially more than .062". It's a lot easier to weld .125" thick aluminum, and weight probably isn't much of an issue for this application. Keep all radii large, for pressure concerns, okay? A round tank with domed ends (similar to an air compressor's tank) would be good. I like the idea of using an existing steel tank, but would make sure it's a new one that hasn't rusted. Good luck. I wouldn't try to economize too much. $39 or so seems too scary for me. A SAE or ASME -approved tank is likely to be pretty safe.
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I took everyone's advice and the result is shown in the attached photo. As you can see I modified an old fuel tank I had in the shop. My calculations show the tank to be around 21.6 gallons. The hold-down straps are 2"x1/8" steel straps that are bolted through the floor with 1/2" bolts and through plates underneath. The remote electric water pump is a Meziere 55 gpm that will feed the mechanical pump on the motor. The AN16 fitting next to the pump is for a drain. I also installed my dry sump tank as you can see in the photos. My total coolant capacity should be around 25 gallons if you include the radiator and hoses. I know some advised to run a pressurized system but I am running it unpressurized for now. I am going to rely on the volume to keep it cool.
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What size vent line did you go to--I noticed you said a 16 drain that size would make a good vent also
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What size vent line did you go to--I noticed you said a 16 drain that size would make a good vent also
I was planning a 8 vent line. I assume you think that is too small.
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The pressure might have to do with air pockets .. STEVE
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I understand the argument that the pressure within the system helps with vapor/air pockets that may form in the high heat areas of the block.
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We don't run any pressure in our system, but take water out of the engine in four places to lessen the chance that air is trapped.
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on my old car I forgot to turn the pump on one time and a 8 ballooned the plaastic fuel tank I was using so bad it pushed a body panel off by ripping and tearing the .062 alum at the Dutz fasteners
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on my old car I forgot to turn the pump on one time and a 8 ballooned the plaastic fuel tank I was using so bad it pushed a body panel off by ripping and tearing the .062 alum at the Dutz fasteners
That is the main reason I decided to run without pressure. Trying to build closed system that could handle an over pressure situation (like a blown head gasket) is too complicated. I am trying to keep things simple. If 25 gallons doesn't keep it cool I'll add more but most seem to think 25 will be more than enough. I added a photo of the electric pump mounted on the tank before I installed it in the car.
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PP the line from the radiator in a box is a 16, the storage tank is non pressurized with an 8 for a vent on my new system. I have an alum tank much like yours a 12 for a vent and I have plans to add another 12
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PP the line from the radiator in a box is a 16, the storage tank is non pressurized with an 8 for a vent on my new system. I have an alum tank much like yours a 12 for a vent and I have plans to add another 12
As you can see on the top of my tank there are two 8AN fittings. One is capped off (blue cap) and other has a red plastic cap on it while I get the hose made. I could easily have two 8AN vents. Are you adding another vent because you anticipate more flow than a single 12 could flow? I could easily add another bulkhead through the floor of the car and add another vent. Keep in mind I am still running a radiator so I can get a fast cool down between runs using the electric pump and the electric fan through the radiator.
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I went back to check and may have over looked---How is the radiator and this tank plumbed?
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I went back to check and may have over looked---How is the radiator and this tank plumbed?
From the electric pump on the tank, through the firewall to the mechanical pump on the motor, through motor to radiator, through radiator to tank, repeat.
I want to be able to cool the water between runs by running the electric pump on the tank and the electric fan on the radiator while the motor is not running. I have already verified that the water will flow past the mechanical pump when it's not running.
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Paul;
If you plumb it with aluminum hard line, its surface area will provide additional cooling.
Regards, Neil Tucson, AZ
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If you have an ice cooler for the induction air presumably that gets drained and refilled bewteen runs - could that water go in the big resevoir tank and bring the engine coolant temp down a little faster?
I am designing with a pressurised radiator mounted in a non-pressurised tank of water acting as a heat sink.
That heat sink tank will probably have a circulating pump.
My expectation is that a drain outlet would be used to take off a few gallons after a run and replace that 'hot water' with the water from the intercooler which started as iced but even if it is all melted it will be colder than what came out of the radiator heat sink tank.
I am using the term intercooler loosely as I will be running naturally aspirated. That 'intercooler' is still on the drawing board.
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If you have an ice cooler for the induction air presumably that gets drained and refilled bewteen runs - could that water go in the big resevoir tank and bring the engine coolant temp down a little faster?
I am designing with a pressurised radiator mounted in a non-pressurised tank of water acting as a heat sink.
That heat sink tank will probably have a circulating pump.
My expectation is that a drain outlet would be used to take off a few gallons after a run and replace that 'hot water' with the water from the intercooler which started as iced but even if it is all melted it will be colder than what came out of the radiator heat sink tank.
I am using the term intercooler loosely as I will be running naturally aspirated. That 'intercooler' is still on the drawing board.
Yes I do have an intercooler for the turbo and I do plan to use that water if necessary to cool the tank water but I don't want to keep draining one tank to fill another. My intercooler holds 12 gallons and draining and refilling it for every run is a pain in the neck. I just want to keep things simple.