I have built an oil burner which uses forced air. I tried many draught type designs but I found them to be unsuitable for the purposes I had in mind and hard to actually put the heat to work. The Burner I have utilises a VW demister Blower and the fuel pump from a Subaru. I have added a speed controll switch which regulates the blower speed which is manily used for start up but could be used where less than full heat output is required. I have also added a needle valve to control oil flow. The burner can be throttled over a pretty wide output.
It does take an amount of preheating but once running it self sustains perfectly. The design is basically a tube in tube design with and tangental air intake. I designed this roughly off the design of early Gas turbine engine burners. At full output with the setup I have it has an output of roughly 500,000 Btu/ Hr or 50 HP. Run flat out it uses a little over 7.5L of oil an hour when it is set to burn a very clean flame. It may use a little more when run slightly rich which seems to produce more heat. With a stronger blower and a higher output fuel pump this could be increased without touching the burner dinentions itself. Improvements could also be incorporated inot the cuttent burner to increase its output from the same blower and fuel pump.
The current design is very good for applications such as a furnace but I believe the addition of a secondary air supply could lower the output temprature to make it more suitable for lighter heat exchangers such as utilising a car radiator etc.
The burner seems happy with any type of oil including used engine ( I know, I know, was just a test :0) ) and transmission oil. Of course my prefered fuel is WVO. Because the burner has no small venturis I just filter the oil through a t-shirt and don't have any problems with blockages. There is no buildup of any residues I can see inside the burner which I think is because it glows dull to bright red while it is operating and any buildup is burnt and blown out. While the burner works well, I think the next thing to making it as practical as possible would be to design some controls and failsafes which would allow it to be left unattended for long periods of time and still work efficently and safely.
My idea is to utilise this burner to heat my pool so now I have to work out how to build an economical and reasonably efficent heat exchanger. I havent done the maths yet but I may build another improved burner and run the 2 together in order to get the time/ temprature rise I want. I have also built some smaller burners which I use for heating waste WVO to make it filter easier and boil off any water.
If anyone is interested I have posted some pics of it heating up my outdoor Pizza oven. www.daretobedifferent.com.au/burner
I have taken some pics at different blower and oil flow settings to show the differences in the flames produced.
Hope this is of some interest. :0)