Re: Stanley Burner Howling
Posted by: Mark Drake
Date: March 14, 2007 09:14AM
I am relatively new to the world of steam cars so please excuse me if I talk a load of ‘hot air’! This ‘burner howl’ is a subject which has really taken my interest as I have a 1921 model 735 which drives quite beautifully, but the burner howls to the extent that I can barely hear anything else on the car. I'm always listening out for mechanical noises to identify trouble early and the howl makes this very difficult! The howl is present even at relatively modest burn rates.
Before I made any changes, I thought it best to talk to some people more experienced than I – but in so doing, I got back as many different answers as times I've asked the question…
However I had some dialogue with David Nergaard who recommended that I looked at the fuel jets first, with a view to checking that the size and fuel mixture was somewhere near correct. He advised me that the richer the mixture, the more likely the burner is to howl. Apparently the fuel jets should be 0.038” (No. 62) diameter. So I dutifully measured mine and found that they were 0.049”! This would explain why I was achieving good burn rates with the burner valve barely open i.e. a relatively low fuel delivery pressure, but the burner howling like hell. For your information, the fuel reservoir pressure is 140psi.
I have now made a new pair of jets and I will try them this coming weekend. I’ve made the jets deliberately undersize at 0.0315”, as it’s an easy job to open them out a little at a time. I expect all sorts of trouble with this small jet size as the mixture is likely to be on the weak side for any given fuel flow rate; but hopefully I may be able to ‘home in’ on a satisfactory combination of jet size / fuel pressure.
As for my theory on burner howl, I think it’s a product of the way that flame front speed is influenced by flow rate, temperature and mixture (and probably lots more)– but I’m sure it’s all been said before…
As luck would have it, I have access to a high-speed camera which can record around 8,000 frames per second for 2 seconds; I thought that I might install a small pyrex window in the burner casing, just above the burner plate and ‘gaze into the fire’ for a bit! I would be really interesting to see what the flame is actually doing close to the burner plate.
I’ll keep you posted on how I get on – good luck to all those other experimenters…