Numerical Simulation for Prediction of Wetness Content in Wet Steam for Convergent - Divergent Nozzle

HUSSEIN WHEEB MASHI

doi:10.31185/ejuow.Vol2.Iss1.20

Authors

HUSSEIN WHEEB MASHI, Dr Department of Mechanical Engineering University of Technology-Baghdad

DOI:

https://doi.org/10.31185/ejuow.Vol2.Iss1.20

Keywords:

Droplet diameter, Wetness, Laser scattering, Mie theory, Supersonic nozzle

Abstract

This research is to find a wetness using the (laser beam) optical Forward Scattering Method (F.S.M.) which is applicable to calculate the wetness in a convergent-divergent De-Laval steam nozzle operating (1.3 Mach number) which may be works at wet steam with pressure (1) bar and temperature (373) K .The light source of He-Ne laser of wave light (λ=0.632) µm was used to prediction the wetness in nozzle a wet steam flow. Both droplet diameter of water (Dr) and relation of intensity of light S= / are assumed to be (Dr=10,30,50,70,100 µm) and (S = 0.9,.0.8,0.7,0.6,0.5 ) respectively. From the relation of light intensity pattern of many diameter droplet of water (Dr) and different droplet size distribution N (Dr), the MATLAB program can calculate the light attenuation coefficient (Ks) consequently. The increase of the droplet size distribution, N (Dr), leads to decrease the values of (S) and (Ks). The increase of the droplet diameter causes increase of the scattered light, and the minimum value of scattering light is with (Dr= 10µm) for the tested samples. The wetness of steam (yₒ) = (1,3,557,10) % ,which depend on the [Dr, N(Dr)] in the scattered zone can be determined easily by the MATLAB program. The radius of droplet water in two – phase can be adversely calculated by using the research output that then the concentrations or wetness is previously specified.

References

[1] K. Tatsuno Center Toshiba Corporation, Kawsaki, “Water Droplet Size measurements in an Experimental Steam Turbine Using an Optical Fiber Droplet Sizer”, Japan, Journal of heat transfer / Vol.108 / 439 / 1, 1986.
[2] Hussien Wheeb Mashi. and Samir Ali Alrabii," Drop Diameter Prediction Model for Liquid Phase Dispersion A Supersonic Nozzle with Wet Steam Flow",Journal of Engneering and Development,Vol.16 p,.4, pp 363-389, 2012.
[3] C.J. Clarke and B. Carswell, "Principles of Astrophysical Fluid Dynamics (1st ed.)". Cambridge University Press. pp. 226. ISBN 978-0-521-85331-6, 2007 .
[4]Avetissian, A. R.; Philippov, G. A. and Zaichik, L. I. (2005),"The effect of turbulence on spontaneously condensing wet-steam flow". Nuclear Engineering and Design, Vol. 235, PP. 1215-1223.
[5] Walter, P. T. and Skingley, P. C., “An Optical Instrument for Measuring the Wetness Fraction and Droplet Size of Wet Steam Flows in LP Turbine”, Inst. Mech. Engrs., C14/79, 1979.
[6] Kantola, R. A., “Condensation in Steam Turbines”, EPRI, CS-2528 RP, 735-1 Aug. 1982 .
[7] Jenkins & White .'Fundamentals of Optics' Fourth edition. ISBN 0-07-085346-0. Chapter 22. Last modified on March 13 2005 .
[8] M. Quinten, "Optical Properties of Nanoparticle systems" Mie and Beyond (Wiley-VCH, Berlin, 2011).
[9] Ederhof, A. and Dibelius, G., “Determination of Droplet Size and Wetness Fraction in Two-Phase-Flows Using a light scattering Technique”, Sixth Thermodynamics and Fluid Mechanics convention, I. Mech. E., C50/76, 1976.
[10]-Danmie Xie ,Xinggang Yu,Woumin Li, Yang Shi,and Sun Cai, "Numerical Simulation of Water Droplets Deposition on the Last – Stage Stationary Blade of Steam Turbine ", School of Power and Mechanical Engineering Wuhan University ,Wuhan , China ,issue2,p p 248- 253,2010.