Dr. Gad A. Pinhasi

 

Dept. of Chemical Engineering,

Ariel University.

Ariel 40700,

Israel.

 

E-mail:       gadip@ariel.ac.il

Phone.:       972-3-9066650

                   972-3-9371469 (Lab)

Fax:            972-3-9066323

 

Research Interests:

 

Computational Fluid Dynamics (CFD)

Two-Phase Flow.

Boiling and Flashing

Heat and Mass Transfer

Environmental Engineering

 

 

Other Academic Activities:

Short Professional Biography
List of Publications
Abstracts
Recent and Current R&D Projects

 

Research Work:

Flames Extinction by means of Electric Field

Boiling and Flashing

BLEVE

Variational Principle in Fluid Dynamics

 

 

GRADUATE STUDENTS

(Co-supervision with Prof. Amos Ullmann)

Dept. of Fluid Mechanics and Heat Transfer, Tel-Aviv University, Israel.)

Matan Peer                      (2006-)      Micro-Pump Development.

Yosef Dahan                   (2006-)      BLEVE Modeling

Itshak  Shtainbach           (2006-)      Variational Principle in Fluid Dynamics

Uri Forberg                     (2008-)      Regenerative heat exchanger

 

Porter School of Environmental Studies, Tel-Aviv University, Israel.

Adi Shapira                     (2008-)      Environmental Risk Assessment Modeling

 

Courses

 

Vector Mechanics,

Fluid-Mechanics,

Thermodynamics,

Heat Transfer,

Control Systems,

Chemical Engineering Lab.

 

 

Other Activities:

 

EDIM BEMADIM: "Witnesses In Uniform": 2007

An Israel Defiance Force (IDF) delegation's mission to Poland in the footsteps of the Holocaust

 

Links

Prof. Yosef PINHASI

                                   

Short Professional Biography

 

EDUCATION

 

B.Sc.

1986-1990

Mechanical Engineering,

Ben-Gurion University, Be'er-Sheva, Israel.

M.Sc.

1990-1992

Mechanical Engineering,

Ben-Gurion University, Be'er-Sheva, Israel.

Ph.D.

1993- 2000

Dept. of Fluid Mechanics and Heat Transfer,

Faculty of Engineering, Tel-Aviv University, Israel.

 

 

Honors and Fellowship Awarded during Studies

Wolf Foundation Award for M.Sc. Research. 1992

Scholarship Fund in the name of Ehud Ben-Amitai, February 1993.

 

 

EMPLOYMENT

 

1990-1992

Research and Teaching Assistant, (Theory of Mechanics)

Department of Mechanical Engineering,

Ben-Gurion University of the Negev.

1993-2000

Research and Teaching Assistant, (Fluid-Mechanics, Air-Conditioning)

Dept. of Fluid Mechanics and Heat Transfer,

Tel-Aviv University, Israel.

1999-now

Lecturer (Vector Mechanics, Control Systems, Fluid-Mechanics, Thermodynamics, Heat Transfer, Chemical Engineering Lab.)

Dept. of Chemical Engineering, Ariel University.

2001-now

Researcher, CTO

Flow-sim Ltd.

 

 

THESISS

 

B.Sc. final project: (with Yoram Puterman) (1990)

"Driving Cycle Simulation of a Vehicle Motored by SI Engine Fueled with H2-Enriched Gasoline".

Supervisor: Prof. Eran Sher.

 M.Sc. Thesis: (1992)

"Extinction of Pool Flames by means of Electric Field"

Supervisor: Prof. Eran Sher.

Ph.D. Thesis: (2001)

"Source Term Modeling of Gas and Liquid Releases from a Breached Pressure Vessel".

 Supervisors: Dr. Abraham Dayan and Dr. Amos Ullmann.

 

 
PROFESSIONAL ORGANIZATION MEMBERSHIP

Member of the American institute for Aerospace & Aeronautics – AIAA

          Since 2001

 

 

 

SCIENTIFIC PUBLICATIONS

 

Hacohen, J., Pinhasi, G., Puterman, Y. and Sher, E. (1991) "Driving Cycle Simulation of a Vehicle Motored by SI Engine Fueled with H2-Enriched Gasoline", Int. J. of Hydrogen Energy, Vol. 16, No. 10, pp. 695-702.

Sher, E., Pinhasi, G., Pokravalo, A. and Bar-On, R. (1993) "Extinction of Pool Flames by means of Electric Field", Combustion and Flame, Vol. 94, pp. 244-252.

Pinhasi, G.A., Dayan, A. and Ullmann, A. (2005) "Modeling of Flashing Two-Phase Flow", Reviews in Chemical Engineering. Vol. 21(3-4), pp. 133-264.

Pinhasi, Y., Yahalom, A., Lurie Y. and Pinhasi, G.A. (2007) “Backward wave excitation and generation of oscillations in distributed gain media and free-electron lasers in the absence of feedback”, IEEE Journal of Quantum Electronics. 43(10), pp. 849-854.

Pinhasi, G.A., Dayan, A. and Ullmann, A., (2007) “1D Plane  <BIG>Numerical Model for Boiling Liquid Expanding Vapor Explosion (BLEVE)", Int. J. Heat Mass Transfer, 50, pp. 4780-4795.

Pinhasi, Y., Yahalom, A., Lurie Y. and Pinhasi, G.A. (2007) “Backward wave excitation and generation of oscillations in distributed gain media and free-electron lasers in the absence of feedback”, IEEE Journal of Quantum Electronics. 43(10), pp. 489-854.

Eliran, A., Gover, A. Pinhasi, Y., Yahalom, A. Luria, Y. and Pinhasi, G.A. (2009) “Statistical Study of Undulator Radiated Power by a Classical Detection System in the mm-Wave Regime”, Physical Review Special Topics- Accelerants and Beams, 12, 050701.

Pinhasi, Y., Yahalom, A. and Pinhasi, G.A. (2009) “Propagation Analysis of Ultra-Short Pulses in Resonant Dielectric Media”, Journal of the Optical Society of America B., 26, (12), 2404-2413.

 

 

PRESENTATION OF PAPERS AT MEETINGS

 

Sher, E., Pinhasi, G., and Puterman, Y., "Driving Cycle Simulation of a SI Engine Fueled with Hydrogen-Enriched Gasoline", 23rd Israeli Conference on Mechanical Engineering, Israel, June 1990.

Sher, E., Jacobson, E., Pokravalo, A. and Pinhasi, G., "Fire Extinguishment of Pool Flames by means of a DC Electric Field", 12th Int. Symposium on Combustion Processes, Bielsko-Biala, Sept., 1991.

Sher, E., Jacobson, E., Pokravalo, A. and Pinhasi, G., "Fire Extinguishment of Pool Flames by means of a DC Electric Field", 7th Int. Israeli Combustion Meeting, Jerusalem, Nov. 1991.

Sher, E., Jacobson, E., Pokravalo, A. and Pinhasi, G., "Fire Extinguishment of Pool Flames by means of a DC Electric Field", Int. Conference on Heterogeneous Combustion, Dead Sea, Israel January 6-10, 1992.

Pinhasi, G., Pokravalo, A. and Sher, E., "On the Electric Wind Formation in Spark Plugs for SI Engines", Int. Conference on Combustion in Engines, ImechE, London, December 1-3 1993.

Pinhasi, G., Dayan, A. and Ullmann, A., "Method of Characteristics Solution for Blowdown Involving Bubbles Break-Up", Mathematics and Computation, Reactor Physics and Environmental Analysis in Nuclear Applications, M&C'99, Madrid, September 1999.

Pinhasi, G., Dayan, A. and Ullmann, “A  <BIG>Numerical Model for Boiling Liquid Vapor Explosion (BLEVE)", The 37th Annual Meeting of the IIChE, IIChE2001, Technion, Israel, April 2001.

Yahalom, A. and Pinhasi, G.A. (2002) "Simulating Fluid Dynamics using a Numerical Variational Principle", Second International Conference on Mathematical Modeling and Computer Simulation of Metal Technologies, MMT-2002, College of Judea and Samaria, Israel.

Yahalom, A. and Pinhasi, G.A. (2002) "Simulating Fluid Dynamics using an Eulerian Variational Principle", 48th annual Meeting of the Israel Physical Society, Weitzman Institute, Rehovot, Israel. December 2002

Yahalom, A. and Pinhasi, G.A., "Simulating Fluid Dynamics using a Numerical Variational Principle", 41st Aerospace Sciences Meeting and Exhibit, 6-9 January, Reno Nevada, AIAA 2003-954, 2003.

Pinhasi, G.A., Dayan, A. and Ullmann, A., “A  <BIG>Numerical Model for Boiling Liquid Expanding Vapor Explosion (BLEVE)", 42nd Aerospace Sciences Meeting and Exhibit, 6-9 January, Reno Nevada. AIAA 2004-161, 2004.

Pinhasi, Y., Yahalom, A., Lurie, Y. and Pinhasi, G.A., “Backward Wave Excitation and Generation of Oscillations in Distributed Gain Media and Free-Electron Lasers in the Absence of Feedback", 26th International Free-Electron Laser Conference, Trieste, Italy (August 30, 2004)

Pinhasi, Y., Yahalom, A., Lurie, Y. and Pinhasi, G.A. “Backward wave excitation and generation of oscillations in distributed gain media and free-electron lasers in the absence of feedback” The 50th Meeting of the Israel Physical Society (IPS 2004).

Yahalom, A., Pinhasi, G.A. and Kopylenko, M., “A Numerical Model Based on Variational Principle for Airfoil and Wing Aerodynamics”, 43rd Aerospace Sciences Meeting and Exhibit, 10-13 January, Reno Nevada, AIAA 2005-0090, 2005.

Pinhasi, G., Dayan, A. and Ullmann, A., "Numerical Model for Bubbles Break-up during Blowdown", 43rd Aerospace Sciences Meeting and Exhibit, 10-13 January, Reno Nevada, AIAA 2005-0383, 2005.

Yahalom, A., Pinhasi, G.A. and Kopylenko, M., "Simulating Fluid Dynamics using a Numerical Variational Principle", ISCM18, Technion, Israel, April 2005.

Yahalom, A., Pinhasi, G.A. and Kopylenko, M. "Simulating Fluid Dynamics using a Numerical Variational Principle", 30th Israeli Conference on Mechanical Engineering, Israel, May, 2005.

Ophir, D., Yahalom, A., Pinhasi, G. and Kopylenko M. “A Combined Variational & Multi-grid Approach for Fluid Simulation” Proceedings of International Conference on Adaptive Modeling and Simulation (ADMOS 2005), 8-10 September 2005, 295-304, Barcelona, Spain.

Ophir, D., Yahalom, A., Pinhasi, G. and Kopylenko M. “A Combined Variational & Multi-grid Approach for Fluid Simulation” Eighteenth Israel Symposium on Computational Mechanics (ISCM-19), The Academic College of Tel-Aviv Yafo, October 27, 2005.

Ophir, D., Yahalom, A., Pinhasi, G. and Kopylenko M., “A combined variational & multi-grid approach for fluid Simulation” The 51th Meeting of the Israel Physical Society (IPS 2005).

Pinhasi, Y., Yahalom, A., and Pinhasi, G.A., “Ultra short pulse propagation in lossy dielectric media”, The 51th Meeting of the Israel Physical Society (IPS 2005).

Pinhasi, Y., Yahalom, A., Lurie, Y. and Pinhasi, G.A. “Backward Wave Excitation and Generation of Oscillations in Distributed Gain Media and Free-Electron Lasers in the Absence of Feedback” 8th Israeli conference on plasma science and applications 2005, The College of Judea and Samaria, Ariel, Israel, 2005.

Pinhasi, Y., Yahalom, A., Lurie, Y. and Pinhasi, G.A. “Backward Wave Excitation and Generation of Oscillations in Distributed Gain Media and Free-Electron Lasers in the Absence of Feedback” Electroptics Convention 16.3.05, Ganei-Hatarucha, Tel-Aviv, Israel, 2005.

Pinhasi, Y., Yahalom, A., Lurie, Y. and Pinhasi, G.A. “Backward Wave Excitation and Generation of Oscillations in Free-Electron Lasers in the Absence of Feedback: Beyond the High Gain Approximation”, 27th International Free-Electron Laser Conference 21-26 August 2005, Stanford, California, USA.

Yahalom, A., Pinhasi, G.A., Kopylenko, M. and Ophir D., “FLUIDEX as a Tool for Aerodynamics Education”, 44rd Aerospace Sciences Meeting and Exhibit, Jan. 9-12, Reno Nevada, AIAA-2006-287, 2006.

Ophir D., Yahalom, A., Pinhasi, G.A. and Kopylenko, M., “A Combined Variational & Multi-Grid Approach for Fluid Simulation”, 44rd Aerospace Sciences Meeting and Exhibit, Jan. 9-12, Reno Nevada, AIAA-2006-695, 2006.

Pinhasi, Y., Yahalom, A., and Pinhasi, G.A., “Propagation of Ultra Short Pulses In Lossy Dielectric Media” Second Israeli conference on THz and Mm-waves Technology and Applications, May 23, 2006, Ariel, Israel.

Pinhasi, G.A., Dayan, A. and Ullmann, A., “A  <BIG>Numerical Model for Boiling Liquid Expanding Vapor Explosion (BLEVE)", ISCM18, Ben-Gurion University, Israel, October 2006.

Ophir, D., Yahalom, A., Pinhasi, G. and Kopylenko M. “A Combined Variational and Multi-grid Approach for Fluid Simulation” IOA seminar, University of Cambridge, Cambridge, United Kingdom (2006).

Ophir, D., Yahalom, A., Pinhasi, G. and Kopylenko M. “A Combined Variational & Multi-grid Approach for Fluid Simulation” Proceedings of International Conference on Adaptive Modeling and Simulation (ADMOS 2005), 8-10 September 2005, 295-304, Barcelona, Spain.

Yahalom, A., Pinhasi, G.A., Kopylenko, M. and Ophir D., “FLUIDEX as a Tool for Aerodynamics Education”, 44rd Aerospace Sciences Meeting and Exhibit, Jan. 9-12, Reno Nevada, AIAA-2006-287, 2006.

Ophir D., Yahalom, A., Pinhasi, G.A. and Kopylenko, M., “A Combined Variational & Multi-Grid Approach for Fluid Simulation”, 44rd Aerospace Sciences Meeting and Exhibit, Jan. 9-12, Reno Nevada, AIAA-2006-695, 2006.

Pinhasi, Y. Yahalom, A. Lurie, Yu. Pinhasi G.A. “Backward Wave Excitation and Generation of Oscillations in Free-Electron Lasers in the Absence of Feedback-Beyond the High Gain Approximation”, The 11th meeting on optical engineering and Science in Israel OASIS 2007 conference, March 27, 2007, Tel-Aviv

Yahalom, A., Pinhasi, G.A., Shtainbach, I and Ullmann, A, "CFD Methods derived from Simplified Variational Principle", 8th. World Congress on Computational Mechanics (WCCM8) and 5th. European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2008), June 30 – July 5, 2008, Venice, Italy

Pinhasi, G.A., Dahan, Y., Dayan, A. and Ullmann, A., "Modeling of Boiling Liquid Expanding Vapor Explosion (BLEVE): Plane, Cylindrical and Spherical 1D model", Proceedings of the 9th Biennial ASME Conference on Engineering Systems Design and Analysis, ESDA08, July 7-9, 2008, Haifa, Israel, ESDA2008-59333.

 

 

SPECIAL SEMINARS

Asher Yahalom and Gad Pinhasi, “Simulating Fluid Dynamics using a Numerical Variational Principle for a non-single valued potential“ Illinois Institute of Technology Fluid Dynamics Center, April 2, 2003 Chicago, Illinois, USA.

Pinhasi, G.A., "Microturbine as a Power Source for Electric Vehicles", AIA conference on Electrochemical Power Sources for High Power Applications, March 3, 2008, IAI Israel.

 

 

PRESENTATION OF POSTERS AT MEETINGS

 

Izvekova, Simon and Pinhasi, "Development of an Air Lift Bioreactor with Immobilized Enzyme", B.Sc. final project, The 42nd annual meeting of the IIChE, 2006.

Yaakov, B., Phitusi, A. and Pinhasi, G.A., "Flame velocity measurements using a Flat flame burner", B.Sc. final project, The 45th annual meeting of the IIChE, 2008. [Poster]

Shapira, A., Pinhasi, G.A. and Ullmann, A, "Consequence analysis of aqueous ammonia spills: Haifa ammonia storage case study", International Preparedness & Response to Emergencies & Disasters: IPRED conference, Tel Aviv, Israel, 11-14.1.2010. [Poster]

Pinhasi, G.A., Dahan, Y., Dayan A. and and Ullmann, A, "BLEVE- Boiling Liquid Expanding Vapor Explosion: Simulation and Risk Analysis", International Preparedness & Response to Emergencies & Disasters: IPRED conference, Tel Aviv, Israel, 11-14.1.2010. [Poster]

 

                                   

PROJECTS

 

Extinction of Pool Flames by Means of a DC Electric Field

E. Sher, G. Pinhasi, A. Pokryvailo and R. Bar-On

Combustion and Flame, 94: 244-252 (1993)

The application of an electric field to a combustion system can produce large and potentially useful effects, such as reducing carbon formation, affecting flame velocity, extending flammability limits, increasing flame luminosity and stabilizing and extinguishing flame. The present study is concerned primarily with the corona discharge interaction with pool fires. The fuel surface served as the blunt electrode and several specially designed sharp probes have been examined as the high-voltage electrode.

The most effective sharp electrode appeared to be a simple thin wire parallel to the liquid surface situated above it at a distance of several millimeters. The flame was repelled from the probe, thus creating a possible pool flame extinction device.  Similar results were achieved with a mechanical blower that reproduced the velocity profile of the electric wind. The gas combination in different locations was examined for both the corona and blower cases. No significant difference was found, and it was concluded that ion pumping has no influence on the extinction performance. It is suggested that extinction by corona discharge is caused solely by the aerodynamic action of the electric wind with its remarkably flat, sharp velocity profile. Fire extinctions under hot and aggressive environments are possible applications of the present device.

 

 

 

 

Modeling of Flashing Two-Phase Flow

Pinhasi, G.A., Dayan, A. and Ullmann, A.

 

Reviews in Chemical Engineering, Vol. 21, Nos. 3-4, 2005.

A review of the published work on the flashing of a two-phase flow system, owing to a sudden depressurization of a compressed liquid, is presented. Of concern is the two-phase flow transient occurring during a failure of a pressurized tube or vessel- blowdown. Abrupt depressurization of a confined liquid can bring the liquid to a superheated state. If this occurs, an intense nucleation process is triggered. The level of superheating at which the nucleation process begins is referred to as the “flashing inception” point. The rapidity of the bubble nucleation and growth processes substantial influence the mixture blowdown scenario that sometimes can be in the form of a Boiling Expanding Vapor Explosion (BLEVE).

The current review deals with flashing of a single pure substance. First, the models of bubble formation and growth are presented. This is followed by a description on the incorporation of these models into two-phase flow transport models. The two-phase models are used for analysis of the blowdown scenario. This subject is of critical importance for the investigation of the safety of compressed liquid systems.

 

 

 

Numerical Model for Boiling Liquid Expanding Vapor Explosion (BLEVE)

Pinhasi, G.A., Dayan, A. and Ullmann, A.

 

Int. J. Heat Mass Transfer, 50, pp. 4780-4795.

International Preparedness & Response to Emergencies & Disasters: IPRED conference, Tel Aviv, Israel, 11-14.1.2010. [Poster]

 

 

The depressurization of a vessel containing saturated or subcooled liquid may occur in a variety of industrial processes and often poses a potentially hazardous situation. A 1D plane numerical model was developed for estimating the thermodynamic and the dynamic state of the boiling liquid during a boiling liquid expanding vapor explosion (BLEVE) event. Based on the choice of the initial nucleation sites density, the model predicts, simultaneously, the bubble growth processes in the liquid at the superheat-limit state, the front velocity of the expanding liquid, and the shock wave pressure formed by the liquid expansion through the air.

Conditions of shock formation were found to be normally associated with high initial temperatures that can bring the liquid to its superheat-limit state during the initial depressurization. Furthermore, the high initial temperature also induces a generation of higher vapor pressures that forces a rapid mixture expansion.

Model predictions of the shock wave strengths, in terms of TNT equivalence, were compared against those obtained by simple energy models. As expected, the simple energy models over predicts the shock wave strength. However, the simple model which accounts for the expansion irreversibility, produces results which are closer to current model predictions.

 

 

 

 

Simulating Fluid Dynamics using a Variational Principle

Yahalom, A., Pinhasi, G.A.

 

FLOWSIM LTD, Ariel, Israel.

Home page:         www.fluidex-cfd.com

 

Over the last few years, finite element algorithms for solution of the Euler flow equations have gained increased popularity. The current work is considered with a new way to solve the flow equations using a variational technique. A computer code named FLUIDEX was developed to analyze barotropic fluid dynamics. The solution of the flow problem is obtained by using numerical algorithm to find the extremum value of an “Action” i.e. by a variational principle.

Predictions of the FLUIDEX numerical model were analyzed for particular cases of potential flow (compressible and incompressible). The results were successfully compared against exact analytical solutions for potential flow test problems and for approximate linearized analytical solution for compressible irorational flow at low Mach numbers. The proposed method obtains fast and stable solutions without the need to integrate the equations in time and space, and thus enables a considerable reduction of the time and cost of the solution.

 

 

 

Environmental Risk Assessment Modeling

Shapira, A., Pinhasi, G.A., and Ullmann, A.

 

International Preparedness & Response to Emergencies & Disasters: IPRED conference, Tel Aviv, Israel, 11-14.1.2010. [Poster]

 

Source term modeling is the key feature in predicting the consequences of releases from hazardous fluids. In some installations, gases, like Ammonia, are refrigerated and stored in low-pressure tanks. Failure of such vessels is unacceptable because of the potentially catastrophic consequences of a highly toxic gas release.

A model was developed for estimating and quantifying the risk poses by refrigerated liquid spills. The research focuses in analysis of cryogenic liquid spill as a source term. The Ammonia vessel (20,000tons) in Haifa bay was taken as a test case.

At the first stage, the newly developed source term model estimates the vaporization rate and net mass evaporating into the air from a spill. At the second stage, four widely-used dense gas dispersion models (ALOHA, HGSYSTEM, SLAB and DEGADIS) were used to calculated downwind Ammonia gas concentrations following the spill scenario. At the last stage a simple dose response model based on the Probit function was used to estimate the number of casualties.

The developed model was used to calculate of risk from the Haifa Ammonia vessel in different scenarios. It is therefore important computational tools for environmental safety assessment.

 

 

 

 

 

Regenerative Heat Exchanger for Microturbine: Theoretical and Experimental Study

 

The study is aimed at the development of an efficient regenerative system, for gas turbine. The present report presents a theoretical study for the heat recovery sub-system: the regenerator. 

Three models were developed with different degree of complexity: from basic mechanistic model to full finite-elements numerical analysis to qualitatively predict the performance of a rotary regenerator.

The current initial survey is based on assumed properties based on Wilson inputs. The present simulation will be used for designing a static 2 chamber model.

 

 

 

 

Electro-Thermal Analysis of Lithium Ion Batteries: Theoretical and Experimental Study

 

 

 

 

 

 

 

 

 

 

 

Student Final Projects

 

Izvekova. J. and Simon, E. (2006) "Development of an Air Lift Bioreactor with Immobilized Enzyme". [Poster]

Yaakov, B., Phitusi, A. and Pinhasi, G.A., "Flame velocity measurements using a Flat flame burner". [Poster]

Shapira, A. (2008) "Absorption Cooling" [Poster]

Klinberg, E. and Genis, I. (2009) "Absorption Cooling" [Poster]

Hofman L. and Azar R. (2009) "RO". [Poster]