Fouling in Heat Exchangers - Part 1
Welcome friends, today we are going to start a new topic related to heat exchangers. This is a very important topic and again this topic will be very vast and there are many aspects but as this is a course on course covering almost all the important aspects of heat exchanger, so we cannot devote much time on a particular aspect or particular topic. So we will try to do with the available time we will try to give you an over view and for students this information will beandand material of this particular topic that has been taken from a particular that is being designed by artist sharkeisha and ADP cycle also we have referred to this book and in our reference we have given this book as one of the book which one need to follow for this particular course all on that matter for knowing it is if we go to the next line this is only the beginning of this we have time to time refer to this particular scene everare on the transfer services limited edition and distribution is known as founding and that will be some sort of extra distance and unless we account for battery is done then there will be here in our estimated capacity of the heat exchanger so I will look into more of a building that is if we go to the slide it is accumulation of undesirable material accumulation of undesirable make deposits on inside go back to the physical and chemical changes of the flu due to the interaction between the fluid and the transfer surface which will be in augmented by the presence of law and transfer to a different kind of deposits there could be crystals there could be sediments volume is cooking cooking products inorganic salts biological growth their growth and product so when I am telling biological and cultural products at least 42 thing you can say that there could be some sort of reaction and this reaction physical changenow things that a new heat exchanger when I am putting in the cistern in I am putting it in the but baby but we'll see later on at the performance of this kind ofbetween fluid and southwest which I explained in significantly on the operating conditions operating conditions florette on the operating condition means sometimes the cleanliness of different which which we are using and obviously pressure-temperature etc even sometimes the environmental condition conditions make me a plan of where is in circulation circulation loop somewhere we have water filter is not operating properly what will happen I am my operating condition has changed and depending on my operating condition I will have different kind of I'm in different aspects of housing project for which there is some sort of anarchy was there and we are supposed tocompany transfer point of view I will not find any difficult but due to the change of the dissolved solids what will be the position on the wall that we share and obviously that we have some effect on the performance and ultimately may be on the serviceability of the life of the texting you this is very important this is a topic of very much or substantial practical of substantial practical importance and one should not blind I put a blind eye to the issues introduction of thermal performance increase the increase is moral accepted that following will reduce the thermal performance and that means what is the heat exchange between the fluids I could have expected at the beginning or expected for the best design or initial design of which time I will find that that has reduced and the patient that will increase so this has got checked and none of these two effects are good for teeth then it made promotion and may result in eventual failure of some YouTubers that almost no fluid is passing through it which is all the prime mover which is attached which is there in the system for circulating the fluid it is unable to circulate the fluid due to very large resistance in the heat exchanger this has not been mentioned over here this may affect the performance of the downstream equipment if there is some sort of a firing order position in the heat exchanger now this deposition or some of the important material can get disclosed and pass with the liquid to the downstream component so that way it may have happened and it may also affect because the downstream equipment may not get the fluid at the equal temperature and frequent depending on the temperaturethat there could be something to eat and the wall of the heat exchanger then following that if the government is produced and then some material will get separated from the heat transfer service and that may create some of the difficultiesbibibop Reading or certification is also one thing that if the temperature goes below sometimes Reading or ice crystals form and the passage so this is also kind of want to get some details of each of these information is available are not frombetween gulf side by founding is very uncommon because the nutrient is lacking in the floor so I guess it is not very conducive for political group in reality more than 1000 mechanism is present in many applications as old one did not think that following will be there in a typical case only for a particular reason it is not that there could be several reasons and favourite type of housing taking place simultaneouslyYouTube you to call us on this will become rough and that may promote wonderfully so this could be some sort of a BCS title kind of a thing is let’s go to the next slide showholding and how the diameter of the tube has reduced so obviously one can think that the the liquid is very much found in plants not only that that a proper servicing probably has not been done time to time so that’s why the tube diameter has reduced to a very large extent to the position inside the inside the tube with me so the question is will it happen only inside the tube outside that you it will not happen no that is not true even outside only will also I will say the Legacy I give you so this could be did you see in which the tubes are old or fixed so you can see that in many cases we cannot see that you we cannot see the area in between the two with so much found so obviously hear the polling has taken place outside the tube also and she had with you bundle has been taken out of the sale to hear clearly one can see that only has taken place probably hear calls and has also taken place the last thing kind of a thing one can see and so when owning is there in case it is not only on the tube service on the bus is also the founding Aztec place so let’s go to the next client this is falling in a playindependence mall and plate heat exchanger to use very clean because the passenger service so somehow if the founding take place so these passages will get you back here we can see very extensively fouled plate of the pill at 16 to get get toothpaste and this howling can give rise to call shin loss of plate in number of places so all these kind of complications may arise due to falling inside of a planeif you clean refrigerant is used and there is a filter in the circulation subside founding will be less rather have we will have more falling on the inside because most of the cases we take a b.m.t. at or let’s say exam hbse application we are taking the mbti and Amy and Ty are we have just entered and if it is not feel that properly so this kind of fouling will take place and then you see which time the following will increase of course the rate of increase did not be the same or uniform throughout the whole different but with time there will be increasing hourly showhear your side on your side letter folding 44 anything to you but not as has been shown to hear what could be found on this kind of things I could say it will be thereI got delayed due to high temperatures that can make some sort of any kind of housing and you can see the bad condition of this one may think and he will not be very long that with this kind of heat exchanger how we transfer is possible only transfer is possible it is also one can think that messages and almost to how floor of a gas will be there because flow of gas tax take place between the passage between the through the passage generated by to excessive heat transfer case and those kind of messages are almost exactly quick styling is there obviously and filings are also present and intestine founding of course some kind of things certain kind of mechanisms are more common in other mechanisms areI mean I do know that cooling tower where is heat transfer direct contact heat transfer between hot water from the plant and the cold ambient air the season opener and what are you there and there are field or the transfer services which supports waterfield where the velocity is relatively low that is very good for biological growth and we can have biofilm formation and biological biological root of 5 housing in this is kind of feelings like precipitation like crystallization shoes kind of our lives are also pregnant this is one thing that one typical kind of hiring and firing of cooling tower feels very common and unless we keep this feeling feels it transfer services time to time the performance of the heat exchanger falls high performance of the cooling tower that falls hospital I have shown you from falling into place and due to corrosion there will be meeting from the surface that will be taken every fall from the surface so there will be picking this is completely different reasons but is also one kind of a mean one reason of picking and the source of corruption are in section of pollution that could be from the from the following to this is another example there are other things due to falling what happened this morning gives rise to call shin andinitially smooth surface was there holding quite difficult to position of material would be difficult to place to place has become rough and it promotes party position of the definition of different kind of one thing one has to be very careful that it may go on increasing in a cyclic order now dogs howling they are our position on the wall of the passage there will be depositing on the wall of the passage is the prices are the passage area will produce which we have seen very quickly if we go for our early are the first diagram show due to falling the passage area initially this was the diameter of the tube that the diameter of the tube has been used of course this writing services become very rough ride and irregular that is one thing but let’s go backSean is proportional to 188 that means hydraulic diameter and density is proportional to one by dhq so this is supplement the ratio of nda the surface area is changing to hear one day we have considered the diameter effect or flowing so if this sorry this condition changes for the transfer coefficient there will be some change and the friction factor that will all change now in if we take a rescue operation drop then it how heat exchanger message and that of the green passage is given by this particular so you see this friction factor is coming and diameter is coming what we can see in a nutshell that would be heat transfer and detailed copy will change and buy a simple analysis it can be shown and that is what we have done I will not proceed further this is just an initiation how pressure drop and heat transfer can be affected by fouling I will take it from this point and in our next lecture I will try to explain what will be the effect of foulingon a transfer and fluid flow. So thank you for your attention.