Heat Pipes and Heat Pipe Heat Exchangers – Part 3





Hello participants so we are again back, we were learning heat pipes and heat pipe exchangers  we will continue with this. So two lectures we had on heat pipes and heat exchangers and there basically we have seen the fundamentals that means the basic construction of the most primitive heat pipe over the years there are different kind of heat pipes which we will see later on. That is one capillary wick supported constant cross section 5 which is which was developed at the beginning and which is still very comprehensively used and most of the week 50 that particular design and then there are certain applications from Portugal today we will move to a important aspect of it bywhat can be done on different level of accuracy for particular one can do at different level of accuracy considering a fully three-dimensional model all the complexities of fluid flow heat transfer case chain excetera one can take care of her taking into consideration all the humans details that can be done that is that maybe very elaborate but that is not impossible but at the same time that may be counterproductive because you see industry cannot have so much of time for designing a file so there could be some sort of model model modelwhat we done yet analysis of a uniform cross section that is what I have told that is the basic structure of if5 uniforms plus and evaporator and condenser section thermal equilibrium between the week and the liquid at any actual location get me Saturday at share location we will assume that the weak structures that is generally the metallic structure most of the cases was activated and liquid within the course of the week they are at the same temperature effect of gravity gravitynext line next line I am showing you one diagram of the hit by you can appreciate by now we have learnt it by so this is big container which is a tubular container in most of the cases or wall of the 85 which is metallic and solid will be really close to the very close to the wall and inside this container there will be some sort of week there could be different design of the week as we have discussed and this is liquid impregnated this is liquid saturate means that will be filled up quickly and they're from the outside if you see the other three sections which I believe you know that is why he is coming inside the it by then there is an adiabatic section there in the intersection almost to know he transferred from the heater at 5 to the surrounding and then there is a concert section where is the heat inside again if we will seecondensed and this liquid will be transported by capillary action back to evaporated and the liquid fluoride is in a direction opposite to the direction ofthere are more or less blank and then these cars which ultimately they're basically and liquid is this kind of the freezer so that is one aspect of that means liquid and that's why you are getting this because a countercurrent kind of money in circulation vapour and liquid floor it has to be supported by some sort of pumping power and that pumping power is coming home from the popularity of the design so this is very important to understand this the following the basic feature ofwhat we have done it will have more than I did very basic level which is called network show people call it sometimes thermodynamic network of basically it is the last element model there are different notes alarms connected by network and basically there will be doing work which you will see these networks are analysed based on an LG electric electric electric electrictypes of network in connection with five people can think of or people have thought of one is purely for the transport of thermal energy and another 40 transport of food that we quickly between networkin the week there will be some sort out probably most probably make structure which is saturated liquid media and the solid wall of the container they contain the solid work and obviously from the evaporator condenser and the lamp alarm and if one wants to do a better analysis then each of the components I have or each of the parts each of the portion I did mention that is evaporative condenser they can be subdivided this is how we get lamps the notes are connected to each other by means of registered capacitive or inductive agents representing different physical phenomenon that is normal or low resistance that is your registered their thermal inertia and Sweden electricity billthese two are very very commonly used for the analysis of such kind of network operation is setupso basically forced at said the life is simple we will have a set of education and if we want to do an analysis that each store will give us one ordinary difference if you can understand that this will be ordinary differential equation and then we have to solve the most probably so this is what is done and all of your 5 through network analysis I have shown a very simplified one can have much more complex but very simplified network or implementing a so if I side by side if I draw it will be clear so that I can make some sort of impression so let’s say this is my kid boy so here is condensation and this is a test and obviously there is liquid floor and in between review all and this week try to see movie into the White that is if I like to write so I can write sorry you have to go back to previous slideand this is your key out okay and then we can see from this from this spot so that outside it is taking once and again going back to the and surrounding r10 r10 is the wall and weak axial resistance resistance elements sometimes their assistance and sometimes they are we have to pay so if it’s over here this is body part of the heat will directly go from the some part of the heat will directly go from the evaporator condenser metallic structure of the wall and of the few that is what has been sold by AT&t and then there is an elaborate this is how it is moving shufflethat is also indeed a radial direction then it has gone to evaporate a liquid vapour interface so again it is in the election and then to the vapour channel through the paper so there will be some sort of action so that is going from here and it is coming to the condenser people liquid interface register then there is condenser with material interface register condenser coil resistance now it has reached the condenser and then it will go to the surrounding through this extra resistance which is outside the wall or just listen to the wall between the wall and the and the surrounding so we can see that there are 21 metallic structures directly from the evaporator condenser is more unless of course they are next flight calculation of register so we can see that our network model we have different kinds of resistances so we can calculate the resistance is the radiologist by this very well known for a circular queue this kind of assistance comes so here there is ri ri ri ri show outer radius radius the conductivity length of the elementary sectional area andnow 50 conductivity we can have by his formula formula formula for the thermal conductivity of the capillary structure can be greeted by so in case of brats in week we will have this kind of the formula where Cayenne is the liquid conductivity kW is the solid conductivity and his silence is the Port of similarly force in did we get this is how we will get the conductivity now if we move to the next slide how can we calculate the capacitance because they will have some confidence and if we consider the tranny and problem then the consideration of capacitance is very important so basically we're talking about this specific so here we have shown we can be calculated the Rosie effect can be calculated doing the porosity of the medicationyou got lot of similarity with electrical get one and we can have a certification like this show is this weekend we will have a number of profit for our competition next slide show us what we will do we will consider how the flu takes place in connection with the heck why I am feeling on the left side and the characteristics of the fruit is on the right hand side and that is what we will try to consider I know you will try to develop what was the fluid flow has to be understood and then it has to be do this day will take a little bit of time so we do it in the next class just now I have introduced, what I we have introduced that what we need to do now. So I like to end this lecture over here. Next lecture we will take the difference of these two diagrams and again we will start from this point. So thank you for your attention.