Is it time to play with a straight bat?

 The last four months have seen India in a sticky wicket, against some hostile bowling from DC.  Our smugness is coming apart from its seams.  Have we lost the art of leaving the ball alone.   Of ensuring that we play with a straight bat.   Sometimes the pitch is undone by the playing 11 and at times by spectators with business interests..

Let’s start with 2022.  A little country gets invaded by a big one.   While we wisely kept out of it in the U.N. we upped the crude oil purchase from zero to 38% of the total mix and it worked as long as we were not in the spotlight.  But we wanted to walk with the swagger of Viv Richards on world stage and the rather partial umpire shouted tarriffs in the middle of a trade war.  Switching to Russian crude was wide off the mark.  That was a ball we could have left alone, soften up the bowling, and quietly caress the ball later for runs. But all the grease has made the wicket nasty.  Is it time to quietly relay the pitch .

The second problem was H1Bs.  A visa system that was meant to attract the very cream, in areas where US is lacking..  chemical engineers who can decipher reaction kinetics while simulating turbulent flow,a  medical researcher that can unlock the autoimmune condition that eats up one’s own nerve cells, material scientists that can invent alloys that make a killer aircraft engine.  Instead Ranji trophy and club cricketers and the like somehow clutter up the queue to do coding jobs under H1B.  I don’t think the Indian government is responsible, but our private enterprises gloss over the letter and spirit of H1B, and now it hits the fan.  

So it is time to settle down and play better cricket,    Leave the greasy ball alone.   Be generous to the grizzly bear, tell them that the Teslas and F120s and Harley’s come in free.  A handful may buy it..  and tell that Chevy Malibu is the best car in the world and play cricket.  With the humility and class of Sachin, with the guile of Prasanna, with a straight bat  and decency like Dravid, with the calm courage of Dhoni.  

To fly like a metallurgist.

Retirement allows one to wheeze like an old wheezer.  While I was in the middle of an asthma episode i get  a call from another retiree who swings golf clubs when free saying why don’t we make our own aircraft engines.  Aircraft engines represent that final frontier in metallurgy.  

The journey probably starts with a propulsion model that provides a system level look of the engine comprising of a turbo fan, which sucks in air from ambient and sends it aft, some through the core and the rest to bye pass the engine whose only purpose is to generate thrust.  The passage of air ingested through a low pressure compressor, high pressure compressor, combustor, high pressure turbine and a low pressure turbine.  At it’s heart is the Brayton cycle that takes in compressed high pressure adiabatically heated air from the compressor into a combustor,  mixing it with fuel and burning it to generate high velocity combustion gases at temperatures that can exceed 1500C. Very close to the melting point of the alloys used.  The high pressure turbine extracts part of that energy converting it to rotational energy which enables the compressor to compress ambient air to higher temperature and pressure and providing further axial thrust as the combustion airplane travels to the aft of the engine.   Further energy is extracted in the low pressure turbine till almost all the useful energy is extracted and the combusted air exits.  Remember the turbofan?   In a commercial engine it is the biggest part of an aircraft engine.  90% of the ingested air travels aft bye passing the core generating thrust.  It’s only 10% that travels through the core, getting compressed, burning the fuel to provide energy for the fan to rotate, and finally exiting as hot air and providing the thrust.  In a military engine we need speed, acceleration, manoeuvrability.  The turbofan is smaller.  Most of the airflow goes through the core; to get the added acceleration an after burner is added at the exhaust.  When fuel is introduced there with exhaust gases already at several hundred Celsius the energy released is tremendous.  The exhaust gases accelerate as they exit, generating tremendous thrust and acceleration.  The Mach 2 velocities come from the after burner. 

Thus from a system design as described above one comes to the mechanical design.  Where each sub system, the compressor, the combustor and high pressure turbine and low pressure turbine is broken down to components.  Each component is reduced to a finite element mesh, where each mesh point is defined by stresses acting on it along with the prevailing temperature. The stress-temperature is in essence an ask from the selected material.  Can it withstand the conditions at each mesh point taking into account failure modes,  yield strength, fatigue strength and creep strength, along with oxidation.  Since each subsystem, such as compressors, turbines and combustors are actually an assembly of components, some welded, some bolted, many sliding to form a fit, relative motion comes into picture and wear remains a matter of concern.  In the high pressure turbine, temperature are so high that it takes a combination of thermal barrier coatings and cooling airflows to keep temperatures where known alloys can operate.   Thus translating the design to practise becomes an exercise in materials selection. 

The rubber starts to hit the road here.  The jet engines we or our parents may have first flown in the 1970s, five decades back still in a Boeing 747 consumed twice the fuel and generated half the thrust compared to the same engines today per passenger kilometer.  Technology has advanced relentlessly.  And with it, so have the designs and materials used.  

So this brings us to why can’t we make an aircraft engine?

Are our designs up to speed. And do we have materials that meet those needs?   Can we manufacture those materials with the required integrity?   Can we life those materials and predict how long will they last.  

The purpose at this point is not to provide a yes or a no to these probing questions.   But articulate a possible strategy to get there.  A cursory review of open domain literature will give us compositions of alloys used for compressors airfoils and disks  turbine airfoils and high pressure turbine disks.  Our first task is to ensure that critical alloy families can be manufactured to the end geometry.  By the required process; disks are forged, high temperature airfoils are cast as directionally solidified grains or as single crystals.  The national labs serve as nuclei where some capabilities exist to cast airfoils as. Single crystals or directionally solidified.  High temperature rotors have alloys which start as powders which are compacted and forged to provide defect free components with required composition.   Can the technology be transferred to a select few private sector companies.  Can private sector companies step forward do their R&D and make the first entry at the component and subassembly level.  

A target for this exercise is to at least reach a point where the select world leaders were at 2000.  In 2000 a twin engine aircraft could fly from London to Singapore.  This could be our Maruti moment in aircraft engines.  But while we are catching up in manufacturing our scientists need to design the next gen aircraft engine with new materials.  The infrastructure created for manufacturing needs to be advanced to make new materials. Simultaneously we need to advance subsystem  level testing capabilities so that designs and manufacturing are continuously validated. 

The road ahead is long.  The key cultural shift that needs to happen is that we need to be ruthlessly honest and recognize the current status and the efforts needed.  But we need to be confident.  Knowing that once we enter the arena we will succeed.  Even if it takes 20 years we will prevail. 

Dr.  Anand K

GE Retiree 

 

A Teachers Day

 Been blessed with great teachers.  A clear but low key”oxygen is a supporter of combustion but not a combustible gas” rings in sometimes even today.  Her name was Susan.  She was as balanced as her equations in chemistry. In College, we had a fair, semi bald headed, with curly hair at the back, teaching physics tell us on October 1st about what Einstein thought of Gandhiji, a physics teachers opinions on someone who held the moral compass. That was Popli…. While I had a bunch wonderful teachers in IISc, here is a special one for Dr Kishore, who would show up at 8 pm on his Rajdooth to see how my experiments were going and ask whether I had dinner.  .. he would take me bike to the machine shop to get the discs ground.  A gentle pat on the back helped me change track from being an aimless wanderer with an engineering degree to someone who fell in love with research, with Tribology, that has stood the test of time and kept me relevant 44 years later.  In IITM it was KAP,  whose concepts  on tensors helped me connect to Peach Koehler formula but more importantly learn who to facilitate others in their pursuits setting aside organisational imperatives.   If KAP reads this he will know. 

During my PhD it was Conrad who hung on to concepts that I had uncovered which Scattergood  nudged me towards, helping me rise from a “oh will i get itmy PhD” to here is a good one.  Kosel in Notre Dame got me to come completely out of my comfort zone, measuring velocity of 100 micron particles rebounding in all directions with a true focus on the fidelity of physics.  

Can a teachers day be complete without writing about Jerry Schell, who knew whether, how and why and where components underwent wear in an aircraft engine and was willing to mentor and teach to anyone who showed up at his doorstep at the end of a 11 hour day.  In those few years I was a pupil again in love with my field, and the engines and coatings and everyone who worked around me. 

I think this continued for life   Finding that Guru in every organization.  There was this Dr Otto Schneiper who knew about every application for thermal sprayed coatings in the industry and tell me about the value story it offered.  

At some point as we get older our ability to soak knowledge like a sponge becomes equal to or less than what we impart.  When we impart do we put blinders on how, or whether we learn?  In my world today i continue to learn from the team, i don’t blank when people talk about repassivation or microstructure based lifing or life limiting locations, or on how to review programs.  But assuming the mantle of a guru should not come in the way of becoming a shishya, a sponge who wants to soak all the knowledge.  

On that note, a Happy Teachers Day.  Happy Pupils day.  Keep your pupil wide open.