SCHOOL OF MECHANICAL ENGINEERING SEMINAR

Monday, 05.08.2024 at 14:00

Wolfson Building of Mechanical Engineering, Room 206

Gas-Liquid Flow in M-Shaped Jumper of Subsea Gas Production Systems

Alexander Yurishchev

Ph.D. student under the supervision of Prof. Amos Ullmann and Prof. Neima Brauner

School of Mechanical Engineering, Tel Aviv University, Israel

Two-phase flow with low liquid loads is common in high-pressure natural gas offshore gathering and transmission pipelines. During gas production slowdowns or shutdowns, an accumulation of liquid in the lower sections of subsea pipelines may occur. The liquid may originate from condensates, water from the reservoir, or from chemicals added to prevent hydrates formation. This phenomenon is observed in jumpers that connect different units in deep-water subsea gas production facilities. The displacement of the accumulated liquid during production ramp-up (or production start-up) induces temporal variations in pressure drop across the jumper and forces on its elbows, resulting in flow-induced vibrations (FIV) that pose potential risks to the structural integrity of the jumper.

The flow phenomena during the liquid displacement process were investigated via transient 3D numerical simulations using OpenFOAM software. The simulation results were validated by lab experiments conducted in a downscaled jumper prototype operating at atmospheric pressure. These simulations facilitated the development of a mechanistic model to elucidate the factors contributing to increased pressure and forces during the liquid purging process. The study examined the influence of gas pressure level, pipe diameter, initially accumulated liquid amount, liquid properties, and gas mass flow rate on the transient pressure drop and the forces acting on the jumper's elbows. The critical gas production rate required for complete liquid removal of the accumulated liquid was determined, and scaling rules were proposed to predict the effects of gas pressure and pipe diameter on this critical value. The dominant frequencies of pressure and force fluctuations were identified, with low-pressure systems exhibiting frequencies associated with two-phase flow phenomena and high-pressure systems showing frequencies attributed to acoustic waves.

School of Mechanical Engineering Seminar
Monday, July, 2024 at 14:00
Wolfson Building of Mechanical Engineering, Room 206

Or Filc

Engineering Solutions to Address Energy Innovation Africa 

Today, approximately half a billion people in Africa live without access to potable water or electricity. For those of us in the developed world, it is hard to imagine such a reality. Simple actions like turning on a water tap or lighting up a room after sunset are almost like science fiction for the remote villages scattered across the African continent. This widespread energy poverty, affecting many countries on the continent, has serious and far-reaching consequences, ranging from direct impacts on public health to limiting children's opportunities for education and their ability to secure a better future.

At Innovation Africa, we aim to confront these challenges using Israeli innovation. Over the past 15 years, we have been actively working in six African countries—Zambia, Malawi, South Africa, Tanzania, Cameroon, and Uganda—to bring clean drinking water and electricity to as many villages, schools, and clinics as possible. With approximately 980 projects completed to date, our technology has positively impacted the lives of over 5 million people across the African continent.

In this lecture, we will explore the energy challenges faced by millions in Africa and examine how energy poverty affects every aspect of life for these populations. We will also discuss the role of technology in addressing these issues, considering both its potential benefits and the challenges it presents. Finally, we will share practical insights on how Innovation Africa is working on the ground to improve the lives of these communities.

Biosketch:

Or Filc is a Graduate of the Adi Lautman Multidisciplinary Excellence Program at Tel Aviv University. She Holds a Master's degree in Mechanical Engineering and a Master's degree in Environmental Sciences. She was previously active in the non-profit organization “Engineers Without Borders”. Currently works as a Mechanical Engineer at Innovation Africa and collaborates with the Society for the Protection of Nature in Israel to develop a position paper on the efficient and wise use of green energy.