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The Numerical Analysis and Experiment of Shock Processing for Bouef. Graduate School of Science and Technology, Kumamoto University YAMASHITA Yusuke. Contents. Introduction Objectives Calculation of parameter Experimental Results Numerical Analysis Conclusion & Future Works.
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The Numerical Analysis and Experiment of Shock Processing for Bouef Graduate School of Science and Technology,KumamotoUniversity YAMASHITAYusuke
Contents • Introduction • Objectives • Calculation of parameter • Experimental Results • Numerical Analysis • Conclusion & Future Works
Introduction In the processing method used for the food processing, there are chiefly heat-treatment and high-pressure processing. • Heat Treatment • High-pressure Treatment There are few changes of the nutrient New physical properties Short processing time Very low energy consumption
Detonation fuse Electric detonator Cage Food Water Shock processing for foods Introduction • The explosive and the high voltage electrical discharge are investigated as the high-pressure source. • The food is processed in water to propagate the shock wave.
Practical use of the shock processing • <Problems> • Strength • Shape • Reflection of shock wave etc.. It is necessary to develop an appropriate food processing vessel where these are considered Objectives Trial and error experimentation can cause damage to the device → We focused Numerical analysis for design
Calculation of numerical analysis parameter of beef[Measurement experiment] Evaluation of accuracy of numerical analysis[Numerical analysis for pressure comparison] Objectives Many parameters for the numerical analysis are need for pressure vessel material and various foods
Necessary parameter in numerical analysis using shock wave Hugoniot equation of state in foods Calculation of numerical analysis parameter Calculation by impedance matching method At the interface of known material A and unknown B, the incidence shock wave velocity and the transmitted shock wave velocity when the shock wave spreads to the interface are necessary, to be measured
Incident shock wave Reflected shock wave Transmitted shock wave A A B B Up Up P P Impedance matching method B and C denote hugoniot points driven in unknowns Shockwave pass on the interface of A and B Generation of reflection wave and transmitted wave Us = C0 + s・upP = ρ0・Us・up This experiment measured theincident and the transmitted shock wave velocityat theinterface of known material PMMA and unknown beef. The velocity of unknown material calculated by thickness of the beef divided by transit time of the shock wave in beef.
Electric Detonator Detonation Fuse SEP(50g) 50mm PVC(VP30) Beef t mm 5mm PMMA block 50mm Streak slit Experimental Condition The shock wave pressure is changed by changing thickness t of the PMMA block
Shooting Procedure (Shadow Graph Method) Window Flash generator IMACON468 HADLAND PHOTONICS interframe times 10ns to 1ms in 10ns steps independently variable, number of channels framing:4 streak:1 Target Closed chamber The experiments were carried out using the high-velocity image converter camera, flash generator and the explosive experimental facilities.
Measurement point Experimental Results (1) The result of experimental number 1( t=50 mm) • The incident shockwave is obtained by plot of shockwave motion. • Penetration shock wave is invisible in beef. • The average velocity was assumed to be a transmitted shock wave velocity shock wave PMMA Photo of incident shock wave Beef (5mm) PMMA 40μs Photo of transmitted shock wave The streak photograph of shock wave Image processing
Experimental Results (2) Experimental number 2 (t = 50 mm) • To calculate the incidence shock wave velocity, the function was approximated to this plot point by using the curve fitting method. • Shockwave velocity of interface PMMA-beef is about 2.93km/s. • Transmitted shockwave velocity is the 2.34km/s. Curve fitting method Incident shockwave velocity Us (PMMA-Beef)
Experimental Results (3) Other experimental results Incident shock wave: Us Transmitted shock wave: U’s
C0 = 1843.8 [m/s] s = 0.547 Us=C0+s・up Experimental Results (3) Hugoniot equation of state
Numerical Analysis • The pressure comparison model of the numerical analysis was written by using hugoniot data obtained from the experimental results. • As shown in this figure, the beef is placed underwater. Another is surrounded by air. Then, a high explosive is exploded. • We compare pressure of the beef in air with that in water. • Each size is asfollowing slide. Model of pressure comparison
200mm 200mm Water Air 100mm 100mm beef beef SUS SUS Water Water 100mm 100mm 60mm 60mm SEP SEP Numerical Analysis Water-beef-Water Air-beef-Water Model of pressure comparison Numerical analysis Parameter of beef [Mie-Grüneisen Parameter] ρ: initial density of the mediumC0, s : Constant of materialΓ0 : Grüneisen coefficient
(1) Numerical Analysis The other analysis conditions • Calculation method: Euler : Explosive (SEP), Water , Beef, SUS , Air • Equation of state: JWL equation :Explosive (SEP) Grüneisen equation: SUS, Beef, Water, Air • Mesh size: 1 x 1 x 1 [mm]element number:31000 • Initial condition: Initial particle velocity : 1711 [m/s] V: 0 (initial density of the explosive)/ (gas density of the detonation) PJWL: pressuree: specific internal energy A, B, R1, R2: JWL parameter η: 1− 0 (initial density of the medium)/ (density) P: pressuree: specific internal energy c0, s: Constants of material 0: Grüneisen coefficient The model was analyzed using LS-DYNA.
Result of Numerical analysis Air-beef-Water
Result of Numerical analysis Water-beef-Water
The comparing pressure value Each pressure history point is as follows. Measurement point (90mm) beef Measurement point Measurement point (40mm)
The comparing pressure value Pressure of beef (Air) Pressure of beef (Water) The pressure history by time in the beef (Air) The pressure history by time in the beef (Water) A pressure value has a difference in the surface (90mm) of beef. It is higher among the water. Therefore, as for shock processing of beef, underwater is better. The comparing of peak pressure
Conclusion • The parameter of the numerical analysis of the beef was obtained by using the impedance match method from a result of the optical observation.Us=C0+s・up ( C0 = 1843.8 [m/s] , S = 0.547) • The process of the spread of the shock wave was analyzed • In the food processing using shock wave, the load pressure value was able to be obtained
Future works Conclusion • Accurate calculation of equation of state • Accurate measurement of shock wave velocity • Appropriate parameter of beef Experiment for beef’s parameter evaluation
Water SUS(φ20) Beef(20×20×5) Measurement point Detonation fuse Future Works Conclusion Experiment for beef’s parameter evaluation For experiment, pressure value is measured by strain gage in SUS. Numerical analysis parameter will evaluate after comparing to experimental value and numerical analysis. Therefore, we will experiment like this in the future (and evaluate the parameter).