Corolisis Effect & Negative Damping – a Report

Report on Thaisen Fan (Scrubber)

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Brief description of the phenomenon:

After cleaning of the fan blades, vibration of the fan gradually increases during operation and in a span of 10 to 14 days vibration level reaches an unacceptable level, which necessitates the next cleaning cycle. However, for so long, this matched the scheduled production window provided by operation. However, after the recent changing of the rotor and the bearings, the fan now reaches unacceptable level of vibration within a short span of time that does not coincide with the scheduled “production window” of the operation, which causes “unplanned downtime.”

Goal of the investigation: To correct the imperfection in the system so that the fan cleaning cycle coincides with.the scheduled production window.

Result of the investigation:

 

1. The problem of rising vibration within a short period of time is an inherent problem (a birth defect) of the fan. The main reason is the Coriolis effect on the fan. Coriolis force is a force exerted by a moving fluid on the disc or impeller rotating in the fluid. If the rotation is CCW (counter clockwise) then the fluid moves to the right of the impeller and away from the centre. Similarly, when the impeller moves in the CW (clockwise direction) the fluid moves towards the left of the impeller and away from the centre.

In this case, with the fan moving in the CCW direction the Coriolis force moves toward the right of the impeller in the same direction as the damping force. This effect (the fan moves in the CCW direction) produces negative damping (since the two forces are in the same line of action).

Negative damping is a phenomenon, when damping force, which usually opposes the driving force, acts in the same direction as the driving force. In such a case the vibration of the system is amplified.

Combination of negative damping and Coriolis effect produces this phenomenon of gradually rising vibration of the fan in a short period of time, which goes away upon regular cleaning. In the present context nothing can be done to eliminate the phenomena of Coriolis Effect and Negative damping. However, if a similar system is to be installed in the future, we would be pleased to provide necessary suggestions and recommendations so that such phenomena are eliminated right from the start.

2. Present signatures indicate misalignment and dynamic imbalance

3. Weak foundations

Actions to be taken to increase the cleaning cycle to match scheduled “production window.”

Countermeasures

1. Take care to align the rotor properly. Care to be taken while putting shims.

2. Dynamically balance the fan in two planes to eliminate the imbalance

3. Cleaning cycle can be initiated when vibration of the fan on the bearings reaches 7 mm/sec (rms). It is safe to run the fan upto this point.

4. Monitor the condition of the foundation by taking vibration measurements in displacement and acceleration modes. Displacement should be taken in the horizontal direction on the topmost accessible point of the columns and at the base.  Acceleration should be taken in both vertical and horizontal directions. Displacement should not cross 50 microns in the horizontal direction or at the base of the columns. Similarly acceleration both in the vertical and horizontal directions must not cross 1.5 g. This would ensure safety of the equipment. In case it crosses corrective actions are to be taken to rectify the foundation.

Result:

After alignment and dynamic balancing in two planes vibrations came down to below 1 mm/sec and maintained its reliability till the next cleaning cycle (10 to 14 days) which matched the scheduled production window of operation — thus avoiding unplanned downtime.
Dibyendu De
dde@rgbwaves.com
9836466678

The Sad Story of the HFO pump

This is a HFO (Heavy Fuel Oil) screw pump used in Power Plant for running boilers. There was a catastrophic failure of the pump. Though this pump was regularly monitored by vibration (in velocity mode — mm/sec) it didn’t give any indication of the impending failure.

The screws of the pump rubbed against each other and the case hardened layers of both screws were crushed. The force was so great that the body of the pump also cracked. Evidence of corrosion was also noticed.

What caused it? 

For want of HFO oil, the plant personnel were forced to pump LDO (Light Diesel Oil) through this HFO pump for the past one year.

Hence the I, A, R factors that contributed to this catastrophic failure are the following:

Initiator(s)I — factor(s), which triggers the problem — low viscosity of LDO compared to that of HFO was the significant ‘initiator’ in this case. While viscosity of LDO ranges from 2.5 to 5 cSt, the viscosity of HFO varies between 30 to 50 cSt (depending on the additives used). Use of lower viscosity oil ensured metal to metal contact thereby increasing Hertz stress that led to collapse of the hardened layer of the screws.

Accelerator(s)A — factor(s), which accelerates the process of failure —  a) Indian HFO does not contain friction modifiers such as vanadium and magnesium. Their absence causes higher friction between the screws (approximately 70 times increase in friction), which accelerates the wear process. b) Moreover, presence of vanadium and magnesium additives in HFO and LDO acts as anti-corrosive agents. Notice that the failure happened a year after the management decided to pump LDO rather than HFO through the HFO pump — enough time for corrosion to take effect. So, we may say that there are at least two factors that accelerated the failure process. There are other effects too on system performance, which we shall discuss in a moment (refer “Note”).

Retarder(s)R — factors that slow down the failure process — a) surface finish of the screws b) right clearance of the bearings c) presence of chromium in the screws.

Surface finish plays a very important role in reduction of metal to metal friction and also allows fluid film development. Ideally the surface finish should be between 3 to 6 microns CLA (Centre Line Average) for best effect. This can be introduced as a specification of the MOC (Material of Construction).

Similarly, excessive clearance in bearings would modify the hertz stress zone or profile — both in width and depth, which would cause shear of the hard layer (depth of which depends on the type of hardening and the type of steel used) and the soft layer (core material). Depth and type of hardening might also be specified in the MOC to prevent failures and extend life of the equipment. Presence of chromium in the metal would help formation of Vanadium – Oxygen – Chromium bond which would effectively enhance the life by providing better lubricating property which in turn would ensure a high level of  reliability of the equipment.

Hence, once the I, A and R s are identified appropriate measures can be taken to modify maintenance plan, MOC etc to ensure long life of the equipment without negative safety consequences (heart of reliability improvement).

Example:

  1. Specify addition of Vanadium and Magnesium in the HFO during supply or these may be added at site after receipt of supply. (Material specification during purchase)
  2. Ensure the right viscosity of oil to be pumps through HFO pumps. (Monitor viscosity of the supply oil — not higher than 50 cSt and not lesser than 30 cSt)
  3. Specify surface roughness of the screws — 3 to 6 microns (CLA).
  4. Specify depth of hardness of the screws (below 580 microns so that the interface between the hard layer and the soft core remains unaffected by the Hertz stress) during procurement and supply. Preferable type of hardening of the screws would be nitriding.
  5. Specify chromium percentage in the screws (during purchase).
  6. Monitor bearing clearance on a regular basis and change as needed (by vibration analysis based on velocity and acceleration parameters).
  7. Monitor the body temperature of the pump to notice adverse frictional effects
  8. Monitor growth of incipient failures in the screws by vibration monitoring (acceleration and displacement parameters)

Note

1. (Effect of IAR on system performance — i.e. the boiler – superheater – pipes):

Problems of high temperature corrosion and brittle deposits drastically impair the performance of high-capacity steam boiler of Power Plants, using HFO. Research* shows that heavy fuel oil (HFO) can be suitably burned in high capacity boilers. However, if HFO is chemically treated with an anticorrosive additives like Vanadium and Magnesium, it diminishes high temperature corrosion that affect some operational parameters  such as the pressure in furnace and pressure drop in superheaters and pipe metal temperature, among others like atomization and combustion processes. Therefore, inclusion of right additives like Vanadium and Magnesium have been found to diminish high-temperature corrosion and improved system performance.  It therefore makes sense to monitor these parameters, which can provide direct information on the degree of fouling, as well as of the effectiveness of the treatment during normal boiler operating conditions.

*Source

2. Effect of Vanadium Oxide nano particles on friction and wear reduction

Ref:

  1. Two approaches to improving Plant Reliability:
  2. Rethinking Maintenance Strategy:
  3. Applying IAR Technique:

By Dibyendu De

Rethinking Maintenance Strategy

As of now, maintenance strategy looks similar to strategy taken by the medical fraternity in themes, concepts and procedures.

If things go suddenly wrong we just fix the problem as quickly as possible. A person is healthy to the point when the person becomes unhealthy.

That might work fine for simple diseases like harmless flu, infections, wounds and fractures. And it is rather necessary to do so during such infrequent periods of crisis.

But that does not work for more serious diseases or chronic ones.

For such serious and chronic ones either we go for preventive measures like general cleanliness, hygiene, food and restoring normal living conditions or predictive measures through regular check ups that detects problems like high or low blood pressures, diabetes and cancer.

Once detected, we treat the symptoms post haste resorting to either prolonged doses of medication or surgery or both, like in the case of cancer. But unfortunately, the chance of survival or prolonging life of a patient is rather low.

However, it is time we rethink our strategy of maintaining health of a human being or any machine or system.

We may do so by orienting our strategy to understand the dynamics of a disease. By doing so, our approach changes radically. For example. let us take Type 2 diabetes, which is becoming a global epidemic. Acute or chronic stress initiates or triggers the disease (Initiator). Poor or inadequate nutrition or wrong choice of food accelerates the process  (Accelerator) whereas taking regular physical exercise retards or slows down the process (Retarder). Worthwhile to mention that the Initiator(s), Accelerator (s) and Retarder (s) get together to produce changes that trigger of unhealthy or undesirable behavior or failure patterns. Such interactions, which I call ‘imperfections‘ between initiator (s), accelerator (s) and retarder (s) change the gene expression which gives rise to a disease, which often has to be treated over the entire lifecycle of a patient or system with a low probability of success.

The present strategy to fight diabetes is to modulate insulin levels through oral medication or injections to keep blood sugar to an acceptable level. It often proves to be a frustrating process for patients to maintain their blood sugar levels in this manner. But more importantly, the present strategy is not geared to reverse Type 2 diabetes or eliminate the disease.

The difference between the two approaches lies in the fact — “respond to the symptom” (high blood sugar) vs “respond to the “imperfection” — the interaction between Initiators, Accelerators and Retarders”. The response to symptom is done through constant monitoring and action based on the condition of the system, without attempting to take care of the inherent imperfections. On the other hand, the response to imperfections involve appropriate and adequate actions around the I, A, R s and monitoring their presence and levels of severity.

So a successful strategy to reverse diabetes would be to eliminate or avoid the initiator (or keep it as low as possible); weaken or eliminate the Accelerator and strengthen or improve the Retarder. A custom made successful strategy might be formulated by careful observation and analysis of the dynamics of the patient.

As a passing note, by following this simple strategy of addressing the “system imperfections“, I could successfully reverse my Type 2 Diabetes, which even doctors considered impossible. Moreover, the consequences of diabetes were also reversed.

Fixing diseases as and when they surface or appear is similar to Breakdown Maintenance strategy, which most industries adopt. Clearly, other than cases where the consequences of a failure is really low, adoption of this strategy is not beneficial in terms of maintenance effort, safety, availability and costs.

As a parallel in engineering, tackling a diseases through preventive measures is like Preventive Maintenance and Total Productive Maintenance — a highly evolved form of Preventive Maintenance. Though such a strategy can prove to be very useful to maintain basic operating conditions, the limitation, as in the case of human beings, is that it does not usually ensure successful ‘mission reliability’  (high chance of survival or prolonging healthy life to the maximum) as demonstrated by Waddington Effect. (You may refer to my posts on Waddington Effect here 1 and here 2)

Similarly, predictive strategy along with its follow up actions in medical science, is similar to Predictive Maintenance, Condition Based Maintenance and Reliability Centered Maintenance in engineering discipline. Though we can successfully avoid or eliminate the consequences of failures; improvement in reliability (extending MTBF — Mean Time Between Failures) or performance is limited to the degree of existing “imperfections” in the system (gene expression of the system), which the above strategies hardly address.

For the purpose of illustration of IAR method, you may like to visit my post on — Application of IAR technique

To summarize, a successful maintenance strategy that aims at zero breakdown and zero safety and performance failures and useful extension of MTBF of any system may be as follows:

  1. Observe the dynamics of the machine or system. This might be done by observing  energy flows or materials movement and its dynamics or vibration patterns or analysis of failure patterns or conducting design audits, etc. Such methods can be employed individually or in combination, which depends on the context.
  2. Understand the failures or abnormal behavior  or performance patterns from equipment history or Review of existing equipment maintenance plan
  3. Identify the Initiators, Accelerators and Retarders (IARs)
  4. Formulate a customized comprehensive strategy  and detailed maintenance and improvement plan around the identified IARs keeping in mind the action principles of elimination, weakening and strengthening the IARs appropriately. This ensures Reliability of Equipment Usage over the lifecycle of an equipment at the lowest possible costs and efforts. The advantage lies in the fact that once done, REU gives ongoing benefits to a manufacturing plant over years.
  5. Keep upgrading the maintenance plan, sensors and analysis algorithms based on new evidences and information. This leads to custom built Artificial Intelligence for any system that proves invaluable in the long run.
  6. Improve the system in small steps that give measureable benefits.By Dibyendu De

 

 

Doing Nothing yet Everything is Done

From 21st June to 23rd June I conducted a live workshop on Streamlined Reliability Centered Maintenance (SRCM) at the Power Management Institute (PMI) of National Thermal Power Corporation (NTPC).

But what the heck is SRCM?

It is a structured process of risk based decision making against black swans.

In brief, it is about:

  1. How to detect an incipient black swan in time?
  2. How to improve the stability of a system?
  3. How to improve the longevity of a system?
  4. How to mitigate consequences of failures?

When we are able to do all that to a system we may call it “smart maintenance.” After all as human beings we create, maintain and destroy systems. Given a system, smart maintenance is about doing all the three – create, maintain and destroy. Surely, it is one of the most complex project management we can engage with.

However, the smart maintenance can really happen when one simply does nothing yet everything is done.

Observing Complexity

To me, observing real life systems is something like this:

A real life System comprises of a meaningful set of objects, diverse in form, state and function but inter-related through multiple network of interdependencies through mutual feedbacks enclosed by variable space, operating far from its equilibrium conditions not only exchanging energy and matter with its environment but also generating internal entropy to undergo discrete transformation triggered by the Arrow of Time forcing it to behave in a dissipative but self organizing manner to either self destruct itself in a wide variety of ways or create new possibilities in performance and/or behaviour owing to presence of ‘attractors’ and ‘bifurcations’; thereby making it impossible to predict the future behaviour of the system in the long term or trace the previous states of the system with any high degree of accuracy other than express it in terms of probabilities since only the present state of the system might be observable to a certain extent and only a probabilistic understanding may be formulated as to how it has arrived at its present state and what would keep it going, thus triggering creative human responses to manage, maintain and enhance the system conditions, function and purpose and create superior systems of the future for the benefit of the society at large.

Such a representation of an observation looks quite involved. Perhaps it might be stated in a much simpler way. Most real life systems behave in a complex manner creating multitude of problems of performance and failures. But how do we get rid of complexity and uncertainty as exhibited by systems? We may do so by deeply observing the complex behaviour of the system to improve our perception to gain insights about the essence of the system; find out the underlying ‘imperfection’ that causes the apparent complexity and uncertainty and then find ways to improve the existing system or create new system and maintain them in the simplest possible manner. We do this by applying the principles of chaos, reliability and design. Surprisingly, the same process might be used to troubleshoot and solve problems we face on a daily basis. If done, we are no longer dominated or dictated by the ‘special whims’ of the system.

The crux of the matter is how we observe reality and understand it so as to make meaningful choices as responses to life and living.

Creative Technique of Joachim Schmid

photoThis is a creation of Joachim Schmid — Photogentic Draft #15, 1991

Problem solving and creativity go hand in hand. So it helps a problem solver to continually hone his creative skills.

Though there are many ways to hone one’s creativity we may always learn a new method to do so from Joachim Schmid.  He creates new images from ‘technically wrong’ images.

This is what he did to create this fine work of art. In this case, he came across a box of negatives, cut in half so they could not be used. Just like putting jigsaw puzzle pieces together – he positioned the different images in odd combinations that created a surprising new image with profound fluidity.

Potential for creative work can just be found anywhere. With this technique we learn how to put together seemingly unrelated images, ideas, thoughts to create a surprisingly new image, idea or thought.

You can see the potential anywhere.

Role of Critical Thinking in Solving Complex Problems

Within the next five years the ability to solve complex problems would be the number one skill people would be desperately looking for.

However, development of this skill rests on three fundamental pillars, which are:

  1. Critical Thinking 
  2. Creativity 
  3. Seeing” things differently

In this post, we focus on the skill of critical thinking. To do so, we draw inspiration from ten examples of critical thinking and critical thinkers that changed our world and our world views.

“Being bold enough to let your mind go where good arguments take you, even if it’s to places that make you feel uncomfortable, may lead you to discoveries about the world and yourself.”

(Critical Thinking: The Art of Argument, by George W. Rainbolt and Sandra L. Dwyer)

Read more

Are ideas really worth 2 Cents?

Ideas are the most profound of products that we as humans generate and possibly the most democratic of all the activities that we ever undertake. The good thing is this is perhaps the only area of human activity where each one of us is “Simply brilliant.” No doubts about that.

Ideas are the fundamental building blocks of creativity. Without such building blocks there would be no stories, no films, no painting, no great scientific discovery, no great analysis or a fine innovation.

Though no one is quite sure about how ideas are generated, idea generation strangely follows some “special laws” which are as follows:

  1. We don’t need any special permission from bosses, spouse, children, friends to come up with a good idea.
  2. This can be done anywhere at anytime without the help of any special gadgets, equipment, environment or even prior practices of any kind.
  3. It can be done in all conceivable positions — sitting down, standing up, standing on your head, lying down, having lunch, strolling in the park or making love in bed.
  4. The best ideas are usually generated even when we are actually not thinking about anything in particular. We can truly celebrate our freedom to conjure up ideas from nowhere — a great luxury.
  5. Generation of ideas does not depend on race, gender, creed, colour, or age. It is truly global and liberating.
  6. And if an idea blossoms at the right place in the right time then of course it holds the raw power to change the course of human history.
So, are ideas really worth 2 cents?

Blank Page Syndrome

The “blank page syndrome” is one of the greatest challenges often faced by professionals, engaged creatively.

We have often heard stories of writers who after putting a blank page into their typewriters keep wondering about what they are going to write. And sometimes they freeze. At times they get frustrated by staring into the blank page for long.

However, this syndrome is not only faced by writers. Whether it is a blank Word document, a blank canvas, or a blank page of a sketch book or a machine that an engineer looks at, the effect is the same. No new ideas flow. It is scary.

As we understand, creativity is the creation of something out of nothing. It is always about creating new knowledge or new interpretation or new explanation of life and the world around us. However, from that “blank page” might suddenly leap into reality a new piece of knowledge, a new painting, a new story, a new poem, a new song, a new explanation that would capture a viewer’s imagination propelling them into another time and space – providing them valuable new insights and new ways of looking at the world and at their lives.

The questions are: How do we overcome the syndrome? How do we start? How do we overcome feelings of possible inadequacy or fear of failure? What is the secret?

The secret, as I see it, is – unless you are deeply inspired don’t create. Once inspired, fear of failure is automatically rejected since it desperately seeks an expression. Love that accompanies inspiration helps new ideas to flow in synchronized pattern. If that is so then what steals or dries up our inspiration?

First, it is our tendency to judge what we come across. More we judge more cynical and depressed we become. I believe that depression and cynical attitude are anti-creative. So, if we suspend our judgement for a while, our chance to be inspired increases exponentially.

Second, our inspiration stops when we expect any specific outcome from our effort of creating something new. Even the mere expectation of expecting people to like what we do can still the creative flow of ideas.

Third, is our fear of non-conformance to the traditional. Thoughts like, “it has always been done this way,” or “people don’t like this way of dressing,” or “it is improper to air my understanding of such and such issues in public,” can freeze us before a “blank page.”

Fourth, is our inability to deeply experience what we come across. More often we do get inspired by what we deeply see and feel. We get inspired when new perspectives, new insights, new knowledge effortlessly pop out from what we deeply experience. Once that happens the inspiration has a life of its own. It flow from the mind to the “blank page.”

In short, getting and staying inspired is the vital ingredient to stay fresh and creative in whatever we do as professionals. It gives us the confidence to succeed. More than that, it always provides the sense of excitement that accompanies being creative. Without fail, that excitement spurs us on in our creative journey.

Possibly a simple way to state this — just play with what interests you. In playing we can simply go anywhere we like and do anything we want to and get whatever we want to get in our imagination.

That is the secret of overcoming the “blank page syndrome.”

There is no need to stare at a “blank page.” When inspiration strikes look for a blank page. 

 

 

 

Creativity in Solving Complex Problems

The other day, at the end of my seminar on “Solving Complex Engineering Problems” a delegate asked me as to whether the entire process of solving complex problems can be automated in some way by means of a software instead of relying on human creativity.

Such a response wasn’t unexpected. In the corporate world the word “creativity” is often looked at with suspicion. They would rather prefer structured and standard approaches like “brainstorming” at 10.00 am sharp or team work or collaborative effort, which in my opinion do little to help anyone solve complex problems or even address complex problems correctly.

That might be the single most important reason why “complex problems” remain unresolved for years affecting profitability and long term sustenance of an organization. Failing to resolve complex problems for years often earns such problems the sobriquet of “wicked problems”, which means that such problems are too tough for “any expert” to come to grips with.

What they sadly miss out is the role of creativity in solving complex problems, which no automation or technology can ever replicate. They miss this because most organizations systemically smother or mercilessly boot out any remnant of creativity in their people since they think that it is always easier to control and manage a regimented workforce devoid of even elementary traces of creativity.

So, is managing creativity and creative people a messy affair? On the surface it seems so. This is simply because we generally have a vague idea of what drives, inspires and really sustains creativity?

Creativity is not about wearing hair long or wearing weird clothes, singing strange tunes, coming to office late and being rude to bosses for no apparent reasons. These things hardly make anyone creative or help anyone become a more creative person.

Actually, things like “being attentive and aware”, “sensitive”, “passionate”, “concerned”, “committed” and above all “inventive” just might be the necessary ingredients to drive, inspire and sustain creativity.

Why?

Though there are many ways of describing and defining creativity what I like best is – “creativity is the expression of one’s understanding and expression of oneself” – deeper the understanding better the expression of creativity.

When we look at creativity in this manner it is obvious that we are all creative though the expression and its fidelity might vary to a great extent. Clearly, some are simply better than others.

Further, if creativity may be thought about as a process, then the inputs and the clarity of understanding of ourselves are more valuable elements of the system than the outputs that the process anyway consistently churns out (remember the uncountable hours we spent in organization meeting, discussing and brainstorming to solve complex problems).

In these days of economic depressions, organizations can really do themselves a huge favor if only they pay more attention to facilitating such inputs to people rather than get overtly worried about control and management by conformity.