Introduction to Regenerators





Welcome to this lecture, in this lecture today we are going to talk about a different type of heat exchanger called regenerators. This is basically a storage type heat exchanger which is in contrast to the recuperators where we have seen two fluids are flowing either in counter-current or in parallel flow at least to exchange their heat. I mean hot fluid will be giving it to the cold fluid and either it will be a direct heatt transfer or it will be you’re separated by a plate or at least some form in one-party rule medium and face will be exchanging it now in this product type of heat exchanger which we call as the originators of this is in contrast to that recuperative it is a story style heat exchanger and he hadaccording to this we have here this is when we have the all kinds of people in this life tubular extended Drive-Ins and this is in contrast to that one we have discretionary did originally fitted and this is different types we’ll talk about it in some of the little ducks what is thehere have a kind of the same freight will be occupying the space in different time what I mean is that by saying so if we look at the degenerative this is basically Idol fixed-rate IRA part-time and sometime we also have the router refrigerated so here’s what we find that the hot scream and the Coldstream they are occupying the same but in different time so if you look into this diagram this is called the fix the door bulb type heat exchanger originated here we find that this is the hot streak which is flowing through this fixed bed which is filledas the staff assist as the Matrix service metrics we will talk about the Matrix in details what are the type of metrics that is possible I mean we generally apply for this type of business and this what we imagine that the valve is in this position and inspirations the fluid is directly flowing from here and passing through these two generators so it will come out from this and it will go to the I’m in process and we’ll wait for this this will she picked up these regenerator metrics will be heated up now after sometime this year metrics is almost reaching to thisso during that time but we will try to do is that they will allow this file to rotate so when we do this so this configuration will look like this and this hot streak will now fill through this that features is occupied or whether this is a matrix features in Aladdin lower-temperature so this will now be cold or other this metrics will be heated up and the first team will now floor or take this will be also you know having a changed position like this and this will come out like this song this heart string of the role of diesel generator basically this complete as it is to make this artist recorded so what will happens when it flows through this date which is at a lower temperature so it will pick up the cold weather and it will in turn make this vision a little water so it will now pass through this configuration so after sometime what will happen now this weight was left heart okay just in the previous cycle is located and then we started driving the floor so this hot scrape through this way now it has been late all week really put it ideal but what did we do is that will suit Coldstream Coldstream through this weight and this Coldstream what happened Coldstream is discount scheme is flowing through this rate and it is picking up that heat which it has led the heart rate late and it heated up this the generator in the earlier side of so now the school freight train is flowing through this and it is picking up this month so during the cycle of course it’s orientation would be like this and it’s orientation will be like this so that this passage I will this cold wait usual park is diverted and this flu is taking place like this and it is sticking out the heat from here and it is getting warm and what's happening to the regenerated Matrix The where is the golden metrics which was there earlier is now being occupied by the Scots so when it is sufficiently called we find that there is no heat exchange between the school fees to which is coming at a constant temperature and it is no more able to pick up heat from this region and it is metrics they will now switch on or the disc switch the halls in its original position now it will keep on this hot schedule again keep on flowing through this bed because this has been to become sufficiently hold it and this date has been sufficiently hot sauce the Coldstream will follow this path usual path and it will follow this way but the hot and the horse he will be flowing through this usual so when it becomes hello again sufficiently hearted this matter is we can submit shortly after all this bill is sufficiently cold and when there is no more hate being exchanged found this of exchange as possible from this way tonight we will I can switch it up switch off her meds I switch over to the other configurations I will this help will be changing them from this position to this position and it will flooring like this where is the hot plate will be flowing through this bit so if alternative cycle you can see this half-baked is having these bags are remaining fixed but only thing is that the walls are changing the floor from 12 generator to the other be tonight so this timing and all she had to finally find out depending on the floor rate of the Matrix of the type of metrics we are using and we will try to solve some numerical example at the appropriate time lol looking into the other type of result is this is called the rotary originated when the bed is not the degenerate matrix is not I’m in a fixed position whether it is so this is the metrics and the other part of the mattresses this one and this isthis is the Oxford they are flowing through this passage is the star that is made for the heart shape and this is for the cold soup so you really going in this direction are in this direction generally they’re mostly in counter current configuration there’s also we can see that they are forming a kind of encounter current configuration so this is the metrics and this mattress is located on this act so when thecome in contact when it is rotating this will come in contact to the old fridge and it will come in the cold so it will be and the regenerated matrix will become cold so when it goes again you know it is continuously rotating so it was coming off and it is in contact with the heart rate and again you know it is transferring in the harm in taking that hit from the hot Floyd and then in the next I mean it is continuously rotating so it will come in contact to the Coldstream periodically periodically the hot iron is this electrics by rotation it is coming in contact to the hot and cold fish sticks so this is contrary to the fixed bed one well we have used up all inside of pulse to drive at the floor where the metrics remain constant thought it was remained fixed where is in contrast to this one here the Matrix tale of the fruit stand in the mainstream of stationary stationary as they are not changing its position where is the metrics will you know continuously rotated between the heart and the forecourt phrase straight to exchange their energy from one side to the other three so they said they're basically two primary types of the regional situation come across in case of rotary I mean in terms of the written originally started in 1860 by buying and it has been adopted independent refrigeration systems particularly unique we find Play store application of this ridiculous and usedround mattresses so this has been one of the old type of packing materials made the random cross roads are the roads are randomly oriented and they close the bacon in line configuration are they can also be putting the staggered configuration has been taken from the London contact details some of the materials are the reason for their generators and also there's open screen mattresses are this is also used as regularly for theLED auto parts of particular diameter depending on the application we can use it to come to 23 mm diameter chart will be there and 2 hours randomly it will be back in it’s fine inside the pipe and to fetch the phrase will be free so if you leave but we know what is basically I meant large surface area and volumes I’m in low pressure drop and obviously high heat transfer coefficient between the equator and the material and of course this is to say that I should have a larger heat capacity of the CP should be high so MCP is the heat capacity of this material selffunction of paper so we had to see we looked we have to be careful particularly surprising applications that it is having considerable amount of specific heat at low temperatures because we know that the city of the material that is with the temperature particularly at low temperatures will be considerably low so we have to take I mean make a notice or take a notice of that one while designing the regional park particularly for the credit applications so if we know what are the formulas are like what are the correlations that we should use for the back bit hair we have an impact bit Spears we have given the correlations of the hit list a door that we need to have a high heat transfer coefficient as well as the location of the low pressure drop so it is important to have high heat transfer coefficient and low pressure trough so we used to know what are the heat transfer and pressure drop characteristics shared in this case in case of packed but we have the school relations for the course it is given in terms of the cold wind chill factor and it is related to this number will come to the definition of the number of the characteristic dimension of this space let alone here for the Reynolds number do we get only for RS 1000 and also we have a full relationship Willoughby park Rd greater than 100000 so we have this 24 relations depending on the er if I lose we had to use either this one or we have to use this correlation for depression factor and that is as you know that it is important for the calculation of the pressure drop when we go for the transfer of the pressure drop calculation we understand that we have to calculate the number and what is important is the characteristic dimension of the system and here in this case the equivalent diameter of the circle with squares is basically given by t e r I mean the equivalent diameter it is defined as the employee transfer 4 x + 4 / the heat transfer area perimeter length and it is finally correlated to the correlation analysis this if he is availablewill be of similar dimensions so we take the average average diameter of this bank Spears and then we calculate the oven this boy and record related to this equivalent the diameter of this pact beer originated pizza next to use the way we know the equivalent diameter or we can try to calculate the mass velocity as it has learnt in our in case of the of the heat exchangers also and that it is it depends on the mass flow rate the fluid that is flowing through the bank and the floor area again it is appearing here this free floor area now can be correlated to the frontal area and the fight so this evening is the point and a ½ is the frontal area of this spanked but if it is a Leica q which is fair with the spanked you know the spheres I don’t normally Spears and this is this becomes the frontal area cross-sectional area because the fertile area of this originated and the mass that is flowing in or out that is basically the most associated with so we have we have the equivalent diameter so we can easilyarea is basically related to the CSR the average diameter of the Earth in diameter of the spare and this is again correlated to the boy and 230 is the volume associated withwe will have only this much it is particularly this particular person meant for you to free state exchanges but if we book this portion or if we did move out a section and this can also be used as the originators with appropriate spaces in between the plates so this is basically made out of copper and it is finally it has been reported with the sales by the recent development in the materials science that which allows us to allow us to use as the original material we have called the middle sponge and this little star is basically of open pores or it can also be closed so basically for original publication with using the open-source used and it has different kinds of porosity and so this is basically a possibility of density of this matter and the horse you can understand that you’re having lads at forces compared to this one and is hurting still smaller number of course so basically this is defined as the ppi post package and this is merely about 5 to 10 for studying playlist this is about 20 PPI and this is nearly 30 PTI now performs solo city is it between range and this metal is used as the original Mercuryin one cycle from this direction to this direction to the heart rate will Detroit from this direction to this direction and this hot plate will in turn heated up these metrics and in the next cycle they will find that the gold rate in Spain through this direction so the school said they will pick up that she it has slipped in the ardea cycle so this regulatory is now heart and the fourth grade is passing through this one and picking up that hit while moving out from this to this direction so it is going in one cycle leaving it sit over here and in the next cycle it is moving from these directions to this direction freaking out that sheet so basically that’s how do storage type of food is near what I will it's basicallyI mean make it into two parts I will part one for the fluid and one for the salad so in the solid part we will write this equation and for the fluid part we write this equation. So a detailed discussion of this equation will be taken up in the next class. Thank you for your attention.