When I started making spray nozzles, I first tried a small 1mm hole in brass which gave a tight water pistol type squirt over a long distance but no spray. Today it occurred to me that I might get spray if two squirts collide kind of like crossing the proton energy streams in Ghostbusters. I tried a two hole nozzle first off and it gives a coarse spray in a fan pattern, next I tried four holes that intersect at a shallow 40 degree included angle, this combined the four streams back into one large stream with no spray. Third time round I'm up to four 0.6mm holes aimed at each other at 90 degrees included angle and they smash into each other and give about a 30 degree solid cone spray unlike my earlier swirl chamber nozzles. The spray is a little coarse for my liking and it drips like crazy so I'll remachine the face and see if that helps things. It's also the simplest nozzle I've made with only one part, five holes and no seals to worry about. I'm guessing it's been done before, but it was fun getting the idea to work.
I noticed last night in one of the comments in ironsides video that he mentions he has a 1/16" hole drilled in the end of his fuel delivery pipe to aid in pressurization, and a pressurized fuel tank. I was not aware of the hole in the end of his fuel pipe. My first oil burner used a cutting torch tip, and it worked with air either in the center hole and the oil in the outer ring of holes, or with air in the outer holes and oil in the center hole. The holes in the top are pretty small for the smallest sized tip, so you may try oil through the outer ring of holes, and block the center hole if you are inclined to try a welding torch tip. Should be interesting to see how your nozzle functions.
Ironsides has a small oil nozzle in one of his videos and has a small but long needle to clear any blockages without removing the assembly. I'm attaching a cross section drawing of this new to me nozzle, it relies on angled holes to collide the jets of fluid and break them apart into droplets. The gas cutting tip has parallel holes so it relies on the oxy/acetylene gases mixing beforehand in a plenum.
I'll tack this latest nozzle development on the end of this nozzle topic rather than create a new one. This is more of a refinement to several earlier swirl pressure nozzles, this one has worked the best so far: I have a spray cone under 5 degrees angle with a flow rate of about 5 to 30 litres per hour flow rate with my 45 PSI car oil gear pump. This time round I resharpened a twist drill by hand to get about a 60 degree point and thinned the drill web so it drills a sharp pointy conical hole. The nozzle hole is 0.65mm and was peck drilled in the lathe. I have noticed that the deeper or longer the nozzle hole is, the sharper the spray cone angle becomes at the expense of droplet size. This nozzle hole is about 4mm long or 3/16" deep before it enters the chamber, inside the chamber is a four slot swirly vane to generate a powerful fluid spin in a tiny chamber before the nozzle hole. The vane just gets poked up the hole where friction and fluid pressure jam it in position. The flow rate should be identical to the earlier 0.65mm unit but the spray seems finer and the cone angle is now under 5 degrees vs 30 degrees of the earlier unit, this is a big deal for me as there should be much less fuel hitting the tuyere pipe and dribbling into the furnace where it can leak out cracks in the refractory. With the combustor fitted I should be able to get the fire well underway before it hits the furnace chamber and have a more complete burn in the furnace. Clockwise from top left: hand grooved/filed vane assembly, 5/8" diameter nozzle body showing 0.65mm nozzle, hand ground pointy drill and 0.65mm drill for comparison. Water test of the nozzle, diesel performs almost identically in terms of flow rate. The background shows a 30 degree angle "Target" for comparison, it's hard to get a good photo due to autofocus. The nozzle and combustor can assembly, have yet to try anything without the combustor can which does seem to allow the flames to begin close to the nozzle. It has heat discolouration despite being away from the furnace chamber.
The best part is you can make the nozzle hole too long/too deep and "tune" it until it works by facing off the end in the lathe. So long as you pay attention to burrs from machining you can get the pattern angle you want. Thanks....just so long as it's not two thumbs up me .
