10 Questions For Bijay Sultanian

In a new feature for the Cambridge University Press Mechanical and Aerospace Engineering Group we are featurng interviews with our members. I am pleased to have Dr. Bijay Sultanian, International Expert in Thermofluids and CFD and Founder & Managing Member of Takaniki Communications, LLC and adjunct Professor at the University of Central Florida as first featured member. Here Bijay tells us about himself and why he decided to become an engineer.

Why did you first study engineering? 

I grew up in a small town in India. My father was a business man. He was exceptionally intelligent with mystifying math skills but became a victim to our family tradition of running a business with minimum schooling. I had the lucky break. He decided to live his own dream in me by supporting my higher education and discouraging my business involvement. Being good in math and science, to become an engineer was the best, and perhaps the only, career option for me. At the time, I didn’t quite know what an engineer really does. I was, however, most fascinated by the changes happening around me in my town to improve people’s life. '

With no electricity, I did most of my high-schooling using a kerosene-powered lantern. Electrification of our town was the greatest boon. Getting my first bike was so joyful; it considerably shrunk my home-to-school commute time. Traveling a distance of forty kilometers on a bullock-cart used to take a whole day, which was later cut down in half by a three wheeler rickshaw – another dramatic change! Going to our railway station to watch trains, gazing at the sky for the rare sight of a plane until it is out of sight, and watching a few cars on the road were all generating within me a deep love for engineering! Little did I know that one day I would be working on the designs of the world’s largest gas turbine (GE90) to propel airplanes and steam-cooled GE-9H and 7H to generate electricity. Understanding the fundamental laws of physics to design new things sounded so very fascinating to me. If I have to do it all over again, I’ll choose engineering!  

Where did you complete your degrees?

All my engineering degrees are in mechanical engineering with specialization in thermofluids and computational fluid dynamics (CFD).  I earned my B.Tech. at Indian Institute of Technology (IIT), Kanpur, in 1971. At that time, there were only five IIT’s in India and the admission to each was only through a country-wide joint entrance examination, selecting around 2,000 students out of 100,000 examinees. I was the first in my entire town to have been ever admitted to an IIT, making the whole town so proud of this outcome. It’s like someone in a remote US suburb gets admitted to MIT or Harvard. I didn’t complete all my degrees in continuity but intermittently with working in industry. I received my MS from IIT, Madras (1978), PhD from Arizona State University, Tempe (1984), and MBA from Rensselaer Polytechnic Institute, Troy (1999). My last degree was sponsored and fully paid for by GE under the Executive MBA program, and it’s my most precious and generous gift from a people-focused company to which I remain ever so grateful.   

When and why did you pick Turbines as your speciality? 

My first job was in liquid rocket propulsion. During the eight-year career, I made landmark contributions towards the design and development of India’s first liquid rocket engine for a surface-to-air missile (Prithvi). In the first few months on the job, I developed a 100-line computer program to run on IBM 1620 to cut down the heat transfer analysis of a regeneratively cooled liquid rocket engine from one month by hand calculations to one day using my program. This is when my passion for numerical heat transfer modeling started and deepened over the subsequent years as the computers became more and more powerful. During my MS at IIT, Madras, I came across the emerging CFD technology. I felt so attracted to this technology that I decided to forego my 10-year career in India and pursue my PhD degree program in CFD at ASU. In this degree program, I worked on the numerical modeling of swirling flows in a sudden pipe expansion, which substantially reinforced my foundation in fluid mechanics and introduced me to many fascinating flow features of a rotating turbulent flow, for example, the vortex-breakdown (on-axis recirculation) in the downstream pipe when the upstream pipe flow has high swirl.

How many of us realize that we are constantly rotating with the earth around its axis at the speed of around 1000 miles per hour?  

But for this rotation, we will have no tornados and hurricanes on earth. Rotation happens to be common to all planets and stars in this vast universe. In 1987, we invited Professor Mike Owen, a leading authority in gas turbine internal air systems, to spend a day at Allison Gas Turbine (now Rolls Royce), Indianapolis. I was truly fascinated by his insight into rotating flows of internal cooling and sealing systems of gas turbines. My passion grew in this intriguing area of gas turbine flow and heat transfer design, and I started CFD-based numerical predictions in rotor cavities. My interest grew further in this area when I joined GE Aircraft Engines (now GE Aviation), Cincinnati, in 1988. Within a year of joining GEAE, I developed a groundbreaking design tool to compute windage and vortex (swirl) in an engine cavity formed by surfaces with arbitrary rotation and orientation. I proudly named this tool BJCAVT, which was popularly called BJCAV. This tool could make design-accurate predictions in minutes rather than hours and days by any other method! In retrospect, five years (1988-93) at GEAE happened to be my best professional years during which I learned the most about gas turbines and contributed the most towards their thermofluids design methods and tools in association with some of the best minds in gas turbine design and technology.

Tell us a bit about what are you working on now? 

In my golden years, with little motivation to earn money, I stay on the path of continuous learning through teaching at the University of Central Florida as an adjunct faculty; volunteering at ASME Turbo Expos to teach workshops, tutorial sessions, and be a Point of Contact for the Heat Transfer Committee, which typically contributes over 200 papers in over 40 sessions; and writing textbooks for the next generation of engineers. Last year, during the fall semester, teaching a graduate class of 53 students using the self-authored textbook Fluid Mechanics: An Intermediate Approach was my most rewarding professional experience yet.

I’m currently working on my next textbook Gas Turbines: Internal Flow Systems Modeling for Cambridge University Press. We currently have a number of titles dealing with the aerodynamic design of compressor and turbine airfoils that directly partake in energy conversion. But only a few titles in the market dwell on the internal flow systems of these complex machines, and they fall short of being directly helpful to practicing gas turbine design engineers. Just as the external power of strong athletes depends on the health of their internal flows of blood, water, and air, so is true for a gas turbine whose operational life depends heavily on the robust design of its internal cooling and sealing flows! I’m really excited about this forthcoming textbook from Cambridge in the hitherto overlooked area of gas turbine design. The book will hopefully last for a long time, until of course a new disruptive technology renders the gas turbines obsolete!

Is there anything you wish you had known before you began your career?

I wish I had known and practiced the following words of wisdom early on in my life: Engineering is not an exact science. Being angry is like punishing yourself for others’ mistakes. Stress is your reaction to an external stimulus – no reaction, no stress! Stop comparing yourself with others; instead, find your own purpose in life.

What is the best advice a colleague or manager has ever given you?

Physics is the foundation of engineering; all our prediction methods and tools used in gas turbine design engineering must, therefore, be physics-based. A quick and dirty solution from a back-of-the-envelope calculation is far better than a wild guess.

What is the best thing about working in your position, what do you enjoy most?

Freedom of retirement from a routine corporate life is priceless, regardless of the position one holds. Now, I can truly focus on doing what I love and loving what I do. That is the essence of success and happiness in life – it’s not about how much wealth I have accumulated so far. I believe in the philosophy of Mahatma Gandhi and try to follow his advice: “Live today as if you were to die tomorrow. Learn today as if you were to live forever.” Other than the technical stuff, I enjoy walking and Indian cooking. My cooking skills have served me well over the years, fully validating the age-old secret of “happy wife, happy life.”

What is the most challenging, and, conversely, rewarding elements of your work?

I remain passionate about the areas of thermodynamics, fluid mechanics, heat transfer, and CFD with emphasis on their applications in gas turbine design engineering. Lack of benchmark quality test data is a big handicap for CFD applications to design. Once I was disillusioned by a set of wrong test data (published in the AIAA journal) while using them to validate my CFD predictions. I asked one of my experimentalist friends for his advice on how to recognize good test data. His advice was “the data that match your predictions are good!” Students in university classrooms and young engineers in gas turbine industry are losing self-motivation for continuous learning. Back-of-the-envelope calculation by engineers is on the verge of extinction. As a result, young engineers are losing feel for the numbers they generate using powerful computer codes. They apply these results to design without a proper sanity check. The most rewarding mission of my remaining life is to reverse some of these trends, bringing practicing engineers and students back to basics and help them master the governing laws of physics, which are foundational to their engineering design activities.

If you had not chosen engineering as career what would you be doing now?

Consistent with our family tradition and the small town upbringing, joining my father to run and expand his business would have been my only other option.  

What trends do you see coming in your area?

Gas turbines for aircraft propulsion and power generation in both simple and combined cycle operations have evolved impressively over the last 70 years. Within the next decade, gas turbine / steam turbine power plants with the combined cycle efficiency of 65% from its current value of 62% will be generating electricity around the world. Key drivers behind efficiency improvement are advances in heat transfer (reduction in cooling and sealing flows) and high-temperature materials technologies. Additive manufacturing (3-D printing) is a fast emerging disruptive technology, which offers enormous geometric flexibility in critical component design, manufacturing, and life management. For the first time, ASME Turbo Expo 2017 is having an Additive Manufacturing Day on June 28, 2017 to showcase the current activities and future potential on how this rapidly developing technology will impact the gas turbine industry." 

CFD technology will continue to make inroads into thermofluids design applications for many critical components of advanced gas turbines. As the computers become more and more powerful and resourceful, large eddy simulation (LES) and direct numerical simulation (DNS) will gradually displace conventional CFD applications in areas where even the advanced turbulence models are found inadequate and unreliable. In view of the continued competitive pressure on reduction in design cycle time, gas turbine companies will spend their resources more and more on integrating various design tools for greater automation. This increase in speed will further weaken engineers’ intuitive understanding of the physics of their design.

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