Two phase flow void fraction measurement using image processing

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Two phase flow void fraction measurement using image processing

  1. 1. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 3, May - June (2013) © IAEME130TWO PHASE FLOW VOID FRACTION MEASUREMENT USINGIMAGE PROCESSING TECHNIQUEManish P. Pujara1, Lav Kumar2, Ashish Mogra31,2,3(Department of Mechanical Engineering, Sardar Vallabhbhai National Institute ofTechnology, Surat-395007, India)ABSTRACTTwo phase flow in mini channel are vital in design and development of thermalsystem such as air- condition system, electronics equipment cooling system. Mini channeloffer superior heat transfer due to their large surface area to volume ratios and the heattransfer rate is a function of the flow pattern, bubble velocity, gas void fraction. Present paperdiscusses review of void fraction measurement techniques and developed void fraction imagesequence algorithm using image processing techniques for void fraction measurement inmini/micro-channelKeywords: image processing, mini-channel, two phase flow, void fraction, void fractionimage sequence algorithm1. INTRODUCTIONVoid fraction is vital property which can be used to differentiate two phase flow fromsingle phase flow. It is key property for determine other important two phase flow propertysuch as• Two phase density• Two phase viscosity• Average velocity of two phase• Pressure drop• Heat transfer coefficientINTERNATIONAL JOURNAL OF MECHANICAL ENGINEERINGAND TECHNOLOGY (IJMET)ISSN 0976 – 6340 (Print)ISSN 0976 – 6359 (Online)Volume 4, Issue 3, May - June (2013), pp. 130-135© IAEME: www.iaeme.com/ijmet.aspJournal Impact Factor (2013): 5.7731 (Calculated by GISI)www.jifactor.comIJMET© I A E M E
  2. 2. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 3, May - June (2013) © IAEME131Void fraction defines many ways such as local void fraction is refer to that at a point,Chordal void fraction is defined as fractional length of path through the channel occupied bygas phase, cross –sectional void fraction is defined as fraction cross-section area of channeloccupied by gas phase and volumetric void fraction in which fraction volume of channeloccupied by gas phase. Application and limitation of different void fraction method shown inTable 1Fu et al [1] measured void fraction by image processing techniques by considering 1000image recorded by high speed camera. Chung et al [3] measured void fraction by imageprocessing in 530 µm, 250 µm, 100 µm, and 50 µm diameter channels. The images wereassigned a void fraction of zero when liquid alone and one for gas alone. Triplett et al [4]measured void fraction by analyzing photograph of different flow pattern such as bubblyflow, slug flow but void fraction measurement for churn flow is difficult. Zhang et al [5]measured void fraction by using neutron radiography and image processing techniques.Saisorn et al [2] measured void fraction by image processing techniques in 0.53, 0.22,0,15mm diameter channel and by quick closing valve in 4.5 mm diameter channel. Kariyasaki etal [8] measured void fraction by constant electric current method in 1, 2.4, and 4.9mm.Table 1 Void Fraction Measurement TechniquesMeasurement techniques Application LimitationIntrusive methodQuick closing valve Volumetric void fractionmeasurementFinite require for closing of the valve,considerable time require for bringingthe system back to the steady statebetween successive experimentConduction probe Local time averaged andchordal void fractionmeasurementLimited to measure bubbly and slugflow regimeNon-intrusive methodBy pressure drop Volumetric void fractionmeasurementFriction pressure drop andacceleration pressure drop neglected ,manometer line filled by single phaseRadiation absorption andscattering methodChordal void fractionmeasurementExpensive ,difficult to handle highenergy radiation ,presence of metalwall induce errorLaser beam method Chordal void fractionmeasurement ,flow patternidentificationExpensivePhotographic method Chordal ,cross-section voidfraction measurementError due to operation perform onimageImpedance method Volumetric void fraction,low cost ,suitable fortransition measurement
  3. 3. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 3, May - June (2013) © IAEME1322. VOID FRACTION IMAGE SEQUENCE ALGORITHMDeveloped Image sequence algorithm is able to measures two phase flow voidfraction, number of bubble, bubble frequency, average slug length.Pre-processing1. Capture two phase video by high resolution digital camera in Fig.12. Captured video of two phase flow is converted to binary video in Fig.13. Find out number of frame required for selected bubble travel from entry to exit ofobserved test section for decide image interval /frame intervalFigure. 1. Captured RGB image of two phase flow is converted to binary image4. Binary video is saved as image sequence for input of void fraction image sequencealgorithmInput parameters1. Image sequence /image file destination2. Total number of frame3. Frame interval for analysis for analysis (avoid repetition of bubble in calculation mainlyfor number of bubble in particular time and reduce calculation time )Void fraction image sequence algorithm1. Read imageImage matrix is M (I, J) (in Fig.2)Where I is for number of row (I=1, 2, 3...................n), J is for number of column (J=1, 2,3....................m).
  4. 4. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 3, May - June (2013) © IAEME133Figure. 2. Image matrix M (I, J)2. Calculate row axis (X which middle horizontal axis ) as show in Fig.22nX =3. Now image pixel value is read at row axis M(X,J)Where if M(X, J) = 255 than bubble length counting start and stop at M(X, J) =0 (whiteportion for gas phase in image has a pixel value 255 and black portion has a pixel value 0)again same process is repeated when M(X, J) = 255. This process repeat in all image whichgive total number of bubble (K=1, 2.............Z), bubble length (LBK) .TNP (Total number of pixel) =number of image used for analysis * number of pixelcalculated on horizontal axis per imageAverage bubble length =ZLBZkK∑=1Where Z is Total number of bubbleChordal void fraction =TNPLBZkK∑=1Output of void fraction image sequence algorithm1. Chordal void fraction2. Bubble frequency3. Number of bubble for particular time duration4. Average bubble length3. CASE STUDYOutput obtained by void fraction image sequence algorithm and void fractioncalculated by Armand correlation show in Table 2 and Fig.3
  5. 5. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 3, May - June (2013) © IAEME134a bc dFigure .3. a) pixel time series ,b) void fraction ,c) bubble length (pixel) ,d) average bubblelength (mm)Table 2 Input and Output of Void fraction image sequence algorithmInput parameters Output parametersTotal number of image 600 Measured Void Fraction(α)(Fig.3-b)0.6233gas volume flow rate (LPM) 0.16 Bubble length (mm) (Fig.3-d) 5.4745Liquid volume flow rate (LPM) 0.05 Number of bubble( 167Frame interval 28 Bubble frequency (number ofbubble/sec)8.3002Analysis time (second) 20 Void fraction by Armandcorrelation ((α=0.83333*β) [6]0.6348β= Qg /(Qg + Ql)=0.76194. CONCLUSIONVoid fraction calculated by image processing techniques is easy, cheap and safe thanother techniques such as quick closing valve, Radiation absorption and scattering method,laser beam. Developed void fraction image sequence algorithm using image processingtechniques calculate void fraction nearly accurate. Void fraction image sequence algorithmalso calculates bubble length, number of bubble, bubble frequency within less time.
  6. 6. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 3, May - June (2013) © IAEME135REFERENCES[1] X.Fu, S.L. Qi, Zhang , R.Z. Wang , Visualization of flow boiling of liquid nitrogen in avertical mini channel, International journal of multiphase flow 34,2008, 333-351.[2] Sira Saisorn , Somchai Wongwises, The Effect Of Channel Diameter On FlowPattern ,Void fraction and pressure drop of two phase air-water flow un circular micro-channel, Experimental thermal and fluid science 34,2010, 454-462.[3] P.M.-Y. Chung, M. Kawaji, The effect of channel diameter on adiabatic two phaseFlow characteristic in micro-channels, International journal of multiphase flow 30,2004,735-761.[4] K.A. Triplett, S.M. Ghiaaasiaan, S.I. Abdel-Khalik, A. LeMouel, B.N. McCord, Gas-liquid two phase liquid in micro-channels Part-II: Void fraction and Pressure drop.International Journal of Multiphase Flow 25), 1999, 395-410.[5] W.Zhang ,T.Hibiki , K.Mishima, Correlation of two phase friction pressure drop andvoid fraction in mini channel. International journal of heat and mass transfer 53, 2010,453-465.[6] A.A. Armand, the resistance during movement of a two phase flow system in horizontalPipes ,Izv.Vses.Teplotech.inst.,1946,1,16-23[7] Alasdair McAndrew, Introduction to Digital Image Processing with MATLAB. 1stedition(Cengage Learning India-1stedition ,2009)[8] A.kariyasaki ,T. Fukano , A. Ousaka & M. Kagawa , Characteristics of time-varyingvoid fraction in isothermal air-water cocurrent flow in a horizontal capillary tube.Trans. JSME (Ser. B) 57, 1991, 4036-4043, in Japanese.[9] www.mathworks.in/help/matlab/index.html[10] http://nptel.iitm.ac.in/courses/103105058/[11] Cherian Paul and Parvathy Venugopal, “Modelling of Interfacial Heat TransferCoefficient and Experimental Verification for Gravity Die Casting of AluminiumAlloys”, International Journal of Mechanical Engineering & Technology (IJMET),Volume 1, Issue 1, 2010, pp. 253 - 274, ISSN Print: 0976 – 6340, ISSN Online: 0976 –6359.[12] Praveer Saxena, Swati Dhamani, Dinesh Chandra, Sampath Kumar V, “Modified TwoPhase Drive Adiabatic Dynamic Cmos Logic”, International Journal of Electronics andCommunication Engineering &Technology (IJECET), Volume 3, Issue 2, 2012,pp. 141 - 147, ISSN Print: 0976- 6464, ISSN Online: 0976 –6472.

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