61 / 100

Dr. Omar Al-Yahia, Reactor Thermal Hydraulics, Best Researcher Award

Doctorate at Paul Scherrer Institut, Switzerland


Dr. Omar Al-Yahia, currently a scientist in the System Behavior group at the Paul Scherrer Institut, is a dedicated professional with a focus on thermal-hydraulic research and development in the field of nuclear systems behavior. His primary objective is to enhance the understanding of best-estimate multiscale thermal-hydraulics computational methodologies, particularly for ensuring the safety of Light Water Reactors (LWR).

Completing his Ph.D. in Mechanical Engineering in 2019 in South Korea, Dr. Al-Yahia has acquired extensive experience as a researcher in the nuclear academic sector. He has been actively involved in advancing codes and methodologies related to the safety analysis of nuclear reactors. His significant contributions extend to various international collaborative projects, including those led by the EU and OECD/NEA. These projects have focused on benchmarking, verification, and validation of Computational Fluid Dynamics (CFD) and system analysis codes.

Professional Profile:

Scopus Profile

Orcid Profile

Google Scholar Profile

👩‍🎓Education & Qualification:

Doctor in Mechanical Engineering (PhD)

  • KNU, South Korea
  • Awarded Brain Korea (BK21) graduate student scholarship for three years consecutively.
  • Research Topic: Influence of Bubble Behavior on Flow Instability under Uniform and Non-Uniform Transverse Heat Distribution.
  • Completion: 02/2019

Advanced Nuclear System Engineering (MSc)

  • KAERI/UST, South Korea
  • Research Topic: Transient Thermal-Hydraulic Analysis for the Downward Flow MTR Research Reactors.
  • Completion: 02/2014

Nuclear Engineering (BSc)

  • JUST, Jordan
  • Research Topic: Jordan Subcritical Assembly Safety Analysis Report.
  • Completion: 06/2011


Dr. Omar Al-Yahia has amassed a distinguished career, making significant contributions to the field of nuclear thermal-hydraulics. Currently serving as a Scientist at the Paul Scherrer Institut (PSI) in Switzerland since August 2021, his responsibilities include conducting system code analysis for light water reactors (LWRs) and providing scientific support to the Swiss nuclear authority (ENSI). Dr. Al-Yahia actively contributes to the development and integration of multi-scale multi-physics analysis methods for LWRs, participating in OECD/NEA and EU projects. His involvement extends to system code development, validation, and subchannel analysis, often incorporating machine learning methodologies. In addition, he supervises graduate students and post-doctoral researchers in his current role.

Before his tenure at PSI, Dr. Al-Yahia held the position of Post-Doctoral Fellow at Khalifa University in the UAE from July 2019 to July 2021. During this period, he engaged in benchmarking, verification, and validation of Computational Fluid Dynamics (CFD) and system analysis codes. He actively participated in international joint projects led by OECD/NEA, focusing on single-phase and two-phase flow heat transfer, reflux condensation, and the development of innovative ceramic ion-exchangers. His role also involved supervising BSc and Master students.

His earlier experiences include a Post-Doctoral Fellowship at Kyungpook National University (KNU) in South Korea (November 2018 – June 2019), where he conducted experimental investigations on two-phase flow boiling. Dr. Al-Yahia also served as a Nuclear Engineer at the Jordan Atomic Energy Commission (JAEC) from June 2014 to February 2015, contributing to thermal-hydraulic safety analysis for the Jordan Research and Training Reactor (JRTR). He further gained research experience as a Research Assistant at the Korea Atomic Energy Research Institute (KAERI) from January 2012 to February 2014, where he was involved in JRTR core thermal-hydraulic design and the development of transient nuclear thermal-hydraulic analysis code.

Dr. Omar Al-Yahia’s extensive background showcases his commitment to advancing nuclear safety through a combination of research, practical application, and active participation in international collaborations.


Dr. Omar Al-Yahia brings a wealth of expertise to the field of nuclear thermal-hydraulics, with a focus on research reactor thermal hydraulic design and transport phenomena in multiphase flows. His background encompasses a wide range of skills and experiences, including:

  • Two-Phase Flow Expertise: Dr. Al-Yahia is well-versed in the hydrodynamics, thermodynamics, nucleation, boiling heat transfer, critical heat flux (CHF), and condensation aspects of two-phase flow phenomena.
  • Computational Analysis: He has extensive experience in utilizing 1-D thermal hydraulics codes such as TRACE, RELAP5, and 3-D Computational Fluid Dynamics (CFD) codes like CFX ANSYS, FLUENT ANSYS, Star-ccm+, OpenFoam, among others. His knowledge extends to various thermal-hydraulics codes, including those used for nuclear and non-nuclear component analysis.
  • Instructorship and Supervision: Dr. Al-Yahia has served as an instructor for the SNAP Workshop at the UAE and has provided guidance to numerous students, including supervision of Master’s students at Khalifa University and Kyungpook National University, as well as post-doctoral and Master’s students at the Paul Scherrer Institut (PSI).
  • Experimental Facility Design: He has played a pivotal role in designing several experimental facilities, encompassing pool boiling, forced convection boiling, and natural convection boiling, both on large and small scales. This includes overseeing the design of facilities for reflux condensation experiments at Khalifa University, subchannel experimental facilities at PSI, and aerosol dispersion studies over urban environments at PSI.

Dr. Omar Al-Yahia’s multidimensional expertise in both computational analysis and experimental facility design underscores his comprehensive understanding of nuclear thermal-hydraulics, making him a valuable contributor to advancements in this critical field.


Dr. Omar Al-Yahia’s remarkable academic and research journey is punctuated by numerous prestigious awards and accolades:

  • Full Scholarship (2007-2011): Dr. Al-Yahia was the recipient of a full scholarship from the King Abdullah II Fund and Development, covering the period from 2007 to 2011.
  • IAEA Fellowship Training: He was awarded an International Atomic Energy Agency (IAEA) fellowship for a six-week training program on research reactors, further enhancing his expertise.
  • Best Scientific Paper Award (2013): Dr. Al-Yahia received the Best Scientific Paper Award in the research reactor technology section, focusing on the reactor system technology topic. This recognition was bestowed at the Transactions of the Korean Nuclear Society Spring Meeting in Gwangju, Korea (May 29-31, 2013).
  • ICONE 25 Qian Sanqiang Best Paper: His exemplary work was acknowledged with the prestigious ICONE 25 Qian Sanqiang Best Paper in the student competition, a testament to the quality of his contributions.
  • Best Paper of the NET Journal: The paper titled “Experimental investigation of convective heat transfer in a narrow rectangular channel for upward and downward flow,” published in Nuclear Engineering and Technology (Volume 46, Pages 195-206), received The Best Paper award in the NET journal, highlighting its outstanding citation records.
  • Graduate Student Awards (2016-2018): Dr. Al-Yahia was honored with Graduate Student Awards in 2016, 2017, and 2018 at Kyungpook National University, recognizing his consistent excellence.
  • Best Paper Award (2018): In 2018, he received the Best Paper Award at Kyungpook National University for the paper titled “Flow Instability (FI) for subcooled flow boiling through a narrow rectangular channel under transversely uniform and non-uniform heat flux,” published in the International Journal of Heat and Mass Transfer (Volume 125, Pages 116-128). This award underscores the significance of his research in the field.

These awards reflect Dr. Omar Al-Yahia’s outstanding contributions, dedication, and impactful research in the domain of nuclear thermal-hydraulics.

Research Interests:

Dr. Omar Al-Yahia’s research interests encompass a broad spectrum of Mechanical and Nuclear Engineering domains. His focus areas include:

  • Experimental and Numerical Thermal-Hydraulics: Conducting research and analysis both experimentally and through numerical simulations in the field of thermal-hydraulics.
  • Small and Large Scale Experimental Analysis: Engaging in experimental studies on varying scales to analyze and understand thermal-hydraulic phenomena.
  • Nuclear Reactor Safety Analysis with System Codes: Investigating safety aspects of nuclear reactors using advanced system codes for analysis and assessment.
  • System Code Development: Contributing to the development of advanced system codes for enhanced nuclear reactor analysis and safety assessment.
  • Multi-phase Flow Modeling: Exploring and modeling multi-phase flows to better understand complex fluid dynamics in various applications.
  • Multi-physics Simulations: Integrating multiple physics principles into simulations to achieve a more comprehensive understanding of complex systems.
  • Machine Learning Methods Application for Safety Analysis: Utilizing machine learning techniques to enhance safety analysis methodologies in the field.
  • Application of High-Performance Computing Methods for Nuclear Safety Assessment: Leveraging high-performance computing methods to conduct efficient and detailed nuclear safety assessments.

Dr. Omar Al-Yahia’s diverse research interests underscore his commitment to advancing the understanding and safety of nuclear systems through a combination of experimental, numerical, and computational approaches.

Publication Top Noted:

Dr. Omar Al-Yahia has made significant contributions to the field of nuclear engineering, particularly in the area of thermal-hydraulic analysis. Here are some of his notable research publications:

“Experimental investigation of convective heat transfer in a narrow rectangular channel for upward and downward flows”

  • Authors: D Jo, OS Al-Yahia, A RAGA’I M, J Park, H Chae
  • Published in Nuclear Engineering and Technology, Volume 46, Issue 2, Pages 195-206, 2014
  • Citation Count: 55

“ONB, OSV, and OFI for subcooled flow boiling through a narrow rectangular channel heated on one-side”

  • Authors: OS Al-Yahia, D Jo
  • Published in International Journal of Heat and Mass Transfer, Volume 116, Pages 136-151, 2018
  • Citation Count: 43

“Onset of Nucleate Boiling for subcooled flow through a one-side heated narrow rectangular channel”

  • Authors: OS Al-Yahia, D Jo
  • Published in Annals of Nuclear Energy, Volume 109, Pages 30-40, 2017
  • Citation Count: 37

“Transient thermal hydraulic analysis of the IAEA 10 MW MTR reactor during Loss of Flow Accident to investigate the flow inversion”

  • Authors: OS AL-Yahia, MA Albati, J Park, H Chae, D Jo
  • Published in Annals of Nuclear Energy, Volume 62, Pages 144-152, 2013
  • Citation Count: 19

“Thermal hydraulic analyses of JRR-3: Code-to-code comparison of COOLOD-N2 and TMAP”

  • Authors: MA Albati, OS AL-Yahia, J Park, H Chae, D Jo
  • Published in Progress in Nuclear Energy, Volume 71, Pages 1-8, 2014
  • Citation Count: 17



Omar Al-Yahia | Reactor Thermal Hydraulics | Best Researcher Award

You May Also Like