
#1
Aug1707, 03:03 AM

P: 4

Hi,
I was just wondering if anyone had any advice on sources of steam ejector design principles. I've seen one textbook on the topic of steam ejectors that is now outofprint, and haven't been able to find any suitable online resources (generally, they're very basic and don't quantify much. They're more along the lines of "make sure the ejector isn't choked with steam"). I would like to go from my design parameters, such as desired suction pressure and steam temperature and pressure to determine nozzle diameter, etc. I realize there are some existing ejector ratios that require only a throat diameter, with all other proportions of the ejector being determined from this value, such as the Langhaar ejector. I suppose I am curious about how to determine a suitable throat diameter in these situations, for instance. I really wanted to get ahold of a paper by DeFrate and Hoerl ... I can't remember the title ... that seemed to go into greater depth than other papers about theory. Anyway, if anyone can suggest any leads or give any advice, it would be greatly appreciated. 



#2
Aug2007, 06:56 AM

Admin
P: 21,637

For what process is one designing a steam ejector.
See  http://www.croll.com/_website/pr/vetheory.asp This might be of interest  http://www.grahammfg.com/downloads/218.pdf I found a couple of papers which reference "L.A. Defrate, A.E. Hoerl, Optimum design of ejector using digital . . . . (1959)", but that is buried in the bibliography of the articles, which must be purchased. Analysis of a vapour ejector refrigeration system with environment friendly refrigerants 



#3
Jun1608, 04:37 PM

P: 1

"investigation of an injector heat pump" investigation of an injector heat pump has some equations related to ejectors. Also Perry's handbook includes the table from DeFrate and Hoerl on page 1057. http://bruceeng.com/thermocompressor...n equation.bmp




#4
Jun1608, 06:56 PM

PF Gold
P: 701

Steam Ejector Design Resources 



#5
Jun1708, 06:33 AM

P: 822

Have you tried the manufacturer's  I remember getting useful info from reading a catalog from (?) Foster Wheeler.




#6
Jul2408, 10:39 AM

P: 1

A onedimension model can be created using compressible flow equations with conservation of mass and momentum. Compressible flow equations are avaible in a undergraduate level fluid mechanics text. These equations will give you the relationship between initial (stagnation) pressure of a fluid and throat diameter and exit diameter and minimum exit pressure ~ refrigerant pressure and prepost shock pressures and etc...
As for mixing efficiency and how close the ejector actually comes to the ideal "turbinecompressor" cycle, htat's more art than science from what I have read... 



#7
Jun1410, 07:44 PM

P: 2

I have read perry's book, jet world, etc.. But they do not clearly explain (may be reason is that my English skill is not good to understand those book) .
My question is : 1) If system needs to suck 1000 kg/hr DAE, does it need to have 1000 kg/hr DAE motive fluid? 2) If ejectors motive fluid is water like venturi scrubber at above system, does it need to have 1 m3/hr motive water (because of density or S.G.)? 3) It is easy to get motive nozzle diameter by critical flow ratio in compressible fluid equation (At dry air, ratio is under 0.53 ). Therefore does ejector venturis throat have diameter which is calculated by critical flow ratio (At dry air, ratio is over 0.53) ? 4) At mixing tank which makes fume, how can I have fumes flow rate? I have calculate it by both liquids reaction heat by temperature and water with reactant flow rate to tank. is it correct solution? 


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