The objective of this experiment is to study the working principles of a concentric tube heat exchanger operating under parallel and counter flow.
Up to this point we have learned how to analyze conduction and convection heat transfer in various systems with different geometries. This information, however, is not very useful unless it can be applied to practical situations. For this reason we shall devote this experiment to a prototypical application of heat transfer analysis known as a heat exchanger.
A heat exchanger is a device that efficiently transfers heat from a warmer fluid to a colder fluid. A device we are probably all familiar with is the automobile radiator. Other applications for heat exchangers are found in heating and air conditioning systems. Heat exchangers are categorized in many ways, but the two most common practices are, by the method of construction, and by the flow arrangements. The analysis for designing an effective heat exchanger is very important; after all who’d want to be caught on the side of a deserted desert road with an overheated engine!
In this experiment we studied a concentric tube heat exchanger with parallel and counter flow. For the analysis of this heat exchanger we needed to find important quantities such as the heat transfer coefficient, power emitted, absorbed, and lost, the log mean temperature difference, and the overall efficiency to compare the two types of flow.
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5. Butter production
6. Material and method
8. Result and Calculation
The porosity distribution and filtrate production during cake filtration in a plate-and frame filter press were simulated mathematically. The model considered filtration that occurs after the filling process, not filtration that occurs as the suspension fills the cell. Governing equations for the temporal porosity distribution were developed for a plate and- frame press. The governing equations were solved numerically. Appropriate initial and boundary conditions were determined based on characteristics of the plate-and-frame press and of the suspension properties
The purpose of this experiment was to learn how plate-and-frame filtrate machine to work and also to determine the filtration constants of K, s, C, m. This experiment was done at two different and constant pressures filtration constants were found by plotting theVP/vs. Vgraph for run 1 and run 2.
In this experiment, the rheological properties of sumac concentrate was determined with different brix values in different temperature ranges (10, 20, 30 oC) and obtain some data related with shear stress, shear rate and viscosity. The graphs which is plotted according to these data was interpreted by Power law and Arrhenius equation and we have found that sumac concentrate shows Non-Newtonion fluid behaviour.
Tray dryers and their developed forms, tunnel dryers are equipments, which found many applications in food operation operations during dehydration of foods. All the drying characteristics of foods can be observed in these equipments.
A typical drying procedure was applied with tray dryer to investigate properties of tray dryers, its advantages or disadvantages, drying kinetics of foods that are dried in tray dryers. For these purposes, equilibrium moisture content, drying rate, mathematical and experimental drying time were calculated with some engineering formulas. Carrot was used as sample for this aim.
The result demonstrated that the most important parameters in drying of foods by tray dryer, which affect the time and the quality of food, are temperature and velocity of air, moisture content of food and surface area that is exposed to heated air. Wet carrot was dried to obtain information about falling rate period, constant rate period, equilibrium moisture content, free moisture content of drying periods, and total drying time was calculated according to results which measured during the experiment on the tray dryer.
By starting out from our experiment, the moisture in dry carrot was reduced from 7.17 into 2.90 (equilibrium moisture content) in tray drier. Total drying time was calculated 96 minutes.
A range of technologies are used for food drying which include tray and tunnel dryers, spray, roller and freeze dryers. With the exception of tray dryers none of these are appropriate, in terms of cost and output, for use by small and medium enterprises.
While sun drying on trays or in solar dryers can be considered as tray drying the term is normally applied to small industrial systems with some form of air heater and a fan to pass air over the product being dried. While small tray dryers are available from Europe and the USA, where they are used in pilot plants and Universities, their cost makes them unaffordable and un-economic for producers in developing countries.
In the early 1980’s; the need for small, controllable, powered tray dryers capable of producing high quality products that could be constructed by engineers in developing countries to a great extent from locally available materials. The required basic development work was carried out and there are now tray dryers, based on the principles developed by some company, in some eight countries. The greatest up-take of the technology has been in Latin America where probably over 100 units are now operational. The key point to bear in mind when considering the local construction of such a dryer is to understand the basic principles involved and adapt them to local conditions such as the dimensions of local plywood sheet, common stock steel sizes, social conditions and fuel availability.
In the work of Chemical engineering, heat exchanger is an essential part of a unit operation. Double pipe heat exchanger is an excellent example to demonstrate the principle of heat transfer using a simple-structured equipment.
In this experiment we worked on concentric tube heat exchanger. The principle of this device is to cool a hot fluid or to heat a cold fluid by using countercurrent or cocurrent flow. The external surface of the exchanger is insulated to minimize losses in the system, hot water is fed through the iner pipe, with cooling water in the outer annulus.
We worked the concentric heat exchanger with different flow rates and different temperatures to measure the THout, TCin and Tcout values.