Heatexchanger may be defined as equipment which transfers the energy from a hot fluid to a cold fluid with maximum rate and minimum investment and running cost. It is used to reduce temperature of one process fluid, which is desirable cool ,by transferring heat to another fluid which is desirable to heat without inter mixing the fluid or changing the physical state of the fluid. Heating is a vital operation in the petroleum and chemical refinery. Hence failure of a heatexchanger result ineffective transfer of energy. Normal operation of heatexchanger usually requires little operator attention .However, operating life of a heatexchanger can be drastically curtailed by improper start up and shut down practices. So properly planed executed maintenance schedule is indispensable for many industries having heat exchangers as a main equipment in their process plant. A detailed maintenance schedule of plant and machinery of an industry involves mainly monitoring without disturbing the operation of the plant as a whole.
The elimination of dead spots on the shell-side and the increased turbulence, both on the shell-side and the tube-side results in reduced fouling. Particulate fouling is reduced by the scouring action. Other types of fouling such as scaling and chemical reaction products are prevented by the removal of hot spots. Flow induced vibration can occur in conventional exchangers although special precautions such as “no tubes in window” are available to overcome the problem by providing more tube support. The most damaging vibration arises from fluid-elastic instability that can lead to damage within a few hours of operation. The possibility of such vibration in twisted tube exchangers is completely eliminated by axial flow and because the tubes are supported approximately every two inches along the tube length.
III. S HELL A ND T UBE H EAT E XCHANGER S YSTEM Shell-and-tubeheat exchangers are probably the most common type of heat exchangers applicable for a wide range of operating temperatures and pressures. Shell-and- tubeheat exchangers find extensive use in refrigeration, power generation, heating and air conditioning, chemical processes, manufacturing, and medical applications.
The heat transfer and flow distribution is discussed in detail and proposed model is compared with the experimental results as well. The model predicts the heat transfer and pressure drop with an average error of 20%. Thus the model still can be improved. The assumption of plane symmetry works well for most of the length of heatexchanger except the outlet and inlet regions where the rapid mixing and change in flow direction takes place. Thus improvement is expected if complete geometry is modeled. Moreover, SST k − ω model has provided the reliable results given the y+ limitations, but this model over predicts the turbulence in regions with large normal strain (i.e. stagnation region at inlet of the shell). Thus the modeling can also be improved by using Reynolds Stress Models, but with higher computational costs. Furthermore, the enhanced wall functions are not used in this project due to convergence issues, but they can be very useful with k − ε models.
The objective of this project is to analyze net heat transfer rate in shell and tubeheatexchanger using nano particle suspended in different base fluids such as Water and Ethylene glycol. The thermophysical properties of naofluid mixture like density, thermal conductivity, specific heat, viscosity and density were predicted by analytical method. Then, the shell and tubeheatexchanger using aluminium metal is created using CATIA and flow and thermal analysis is created using ANASYS.
4. Baffles: It is apparent that higher heat transfer coefficient results when the liquid is maintained in the state of turbulence. To induce turbulence outside the tube it is customary to employ baffles, which cause the liquid to flow through the shell at right angles to the exit of the tubes. Baffles serve two functions: Most importantly, they support the tubes in the proper position during assembly and operation and prevent vibration of the tubes caused by flow-induced eddies, and secondly, they guide the shell-side flow back and forth across the tube field, increasing the velocity and the heat transfer coefficient (Jaydeep et al., ). In this project, the baffles machined were made from galvanized steel which is compatible with the shell side fluid. The tube holes must be precise enough to allow easy assembly and field tube replacement, yet minimize the chance of fluid flowing between the tube wall and baffle hole, resulting in reduced thermal performance and increased potential for tube wall cutting from vibration. Baffles do not extend edge to edge, but have a cut that allows shell side fluid to flow to the next baffled chamber. For most liquid applications, the cuts areas represent 20-25% of the shell diameter. In this project cuts areas of 25% was adopted.
The mesh is checked and quality is ensured. The analysis type is altered to Pressure Based type. The velocity formulation is assigned as ‘absolute’ and time to ‘steady state’. Energy option is set to ON. Viscous model is selected as “k-ε model”. The create/edit option is clicked to add water- liquid, copper, stainless steel, brass, ASTM A 179, C12200 materials to the list of fluid and solid respectively from the fluent database. But vast majority of the industrial alloys are unavailable in Fluent default data base. So, we have to create a user defined database ‘.scm’ file and use it for material assignment.
The efficiency equation assumes a uniform air and fin temperature, which is not the case practically. The local convective heat transfer coefficient changes across the fin according to the temperature variation. The heat transfer coefficient is determined by assuming the steady fluid flow analysis. But actually the temperature of the fins and copper tubes changes with respect to time, hence transient flow analysis can also be taken into consideration. Further fine mesh can also be used to increase the accuracy of results. In our project structural grids are used but hybrid or unstructured grids can be used.
The comprehensive experimental investigation on the augmentation of heat transfer coefficients and pressure drop during condensation of HFC-134a in a horizontal tube at the presence of different twisted tape inserts was carried out in . The experiments were performed for a plain tube and four tubes with twisted tapes inserts of 6, 9, 12 and 15 twist ratios. Similarly, the numerical and ex- perimental investigations to understand convective heat transfer from a single round pipe coiled in rectangular pattern are presented in  where the studied heat ex- changers were composed with inner and outer coils so that the exterior flow is very similar to flow within tube- bundles. The inner and outer coils of the heat exchangers are in turn composed of bends and straight portions. The investigation of the flow field and the heat transfer char- acteristics of a shell-and-tubeheatexchanger for the cooling of syngas were carried out in  in which the finite volume method based on FLUENT software and the turbulence model was adopted for modeling turbulent flow. The pressure drop, the temperature distribution and the variation of local heat transfer were studied under the effects of the syngas components and the operating pre- ssure, and the effect of the arrangement of the baffles on the heat transfer has been studied.
A Shell and tubeheatexchanger is a class of heatexchanger. It is the most common type of heatexchanger in oil refineries and other large chemical processes. As its name implies, this type of heatexchanger consists of a shell (a large vessel) with a bundle of tubes inside it. Thermal design of shell-and-tubeheat exchangers (STHEs) is done by sophisticated computer software. However, a good understanding of the underlying principles of exchanger design is needed to use this software effectively. This article explains the basics of exchanger thermal design, covering such topics as: STHE components; classification of STHEs according to construction and according to service; data needed for thermal design; tube side design; shell side design, including tube layout, baffling, and shell side pressure drop; and mean temperature difference. The basic equations for tube side and shell side heat transfer and pressure drop are well known; here we focus on the application of these correlations for the optimum design of heat exchangers. A follow-up article on advanced topics in shell-and-tubeheatexchanger design, such as allocation of shell side and tube side fluids, use of multiple shells, overdesign, and fouling, is scheduled to appear in the next issue.
Andre L.H. Costa and Eduardo M. Queiroz  presented a paper which deals with study about the design optimization of shell-and- tubeheat exchangers. The formulated problem consists of the minimization of the thermal surface area for a certain service, involving discrete decision variables. Additional constraints represent geometrical features and velocity conditions which must be complied in order to reach a more realistic solution for the process task. The optimization algorithm is based on a search along the tube count table where the established constraints and the investigated design candidates are employed to eliminate non optimal alternatives, thus reducing the number of rating runs executed.
Abstract- Shell and tubeheat exchangers are used extensively throughout the process industry. Vibration of tubes in heat exchangers is an important limiting factor in heatexchanger operation. One of the design specification on which vibration is dependent is the unsupported tube length which is a function of baffle spacing. In this paper, the vibration analysis for the shell and tubeheatexchanger is carried out at different values of baffle spacing using CHEMCAD. The change in the values of various vibration mechanisms is noted by changing the baffle spacing of a shell with single segmental baffles at 0.072m, 0.076m and 0.08m. The changes in the cross-flow velocity, critical velocity, natural frequency, vortex shedding frequency and turbulent buffeting frequency throughout the length of tube of the heatexchanger are studied.
tube surface is maintained at 100 microns to capture the velocity and thermal boundary layers. The discretized model is checked for quality and is found to have a minimum angle of 18° and min determinant of 4.12. Once the meshes are checked for free of errors and minimum required quality it is exported to ANSYS CFX pre- processor.
A heatexchanger is a gadget that is utilized to transfer warm vitality (enthalpy) between at least two liquids, between a strong surface and a liquid, or between strong particulates and a liquid, at various temperatures and in warm contact. In heat exchangers, there are typically no outside heat and work communications. Run of the mill applications include heating or cooling of a liquid stream of concern and dissipation or build-up of single-or multicomponent liquid streams.
STHX. From the CFD simulation results, the shell side outlet temperature, pressure drop, optimum baffle inclination and optimal mass flow rate were determined. m Neeraj kumar, Dr. Pradeep kumar Jhinge,  studied effect of segmental baffles at different orientation on the performances of single pass shell and tubeheatexchanger. In this paper, experimentation of single pass, counter flow shell and tubeheatexchanger containing segmental baffles at different orientations has been conducted to calculate some parameters (heat transfer rate and pressure drop) at different Reynolds number in laminar flow. In the present work, an attempt has been made to study the effect of increase in Reynolds number at different angular orientation “θ” of the baffles. The range of “θ” vary from 0° to 45° (i.e 0°, 15°, 30° and 45°) and Reynolds number ranges from 500 to 2000 (i.e 500, 1000, 1500 and 2000). Based on the experimental result it has been observed that the angular orientation of baffles and the Reynolds number effects the heat transfer rate and pressure drop in the shell and tubeheatexchanger. The heat transfer rate increases up to 30° angular orientation of the baffles and after that there is a drop in heat transfer rate at θ = 45°.
The objective of this work is to improve the performance characteristics of a high viscous non-edible vegetable oil as alternative fuel to diesel fuel. The pre-heating process of fuel is used to reduce the viscosity of high viscous fuels. A double pipe heatexchanger is used to operate using the heat of engine exhaust. A bypass valve is used to control the mass flow rate of exhaust gas to heatexchanger. A single cylinder diesel engine is used for testing. The necessary arrangements are done to attach the heatexchanger to engine. The engine is tested with biodiesel. The heatexchanger design is made using CATIA V5 software. The heat exchangers are analyzed using ANSYS FLUENT. The results are compared and the suitable heatexchanger is proposed.
Fig. 2.1 Schematic Diagram of experimental layout In this experimental work ,Water from water storage is pumped by a pump ,from pump is passed through flow control valve and then passed through flow meter then entered in a shell side of heatexchanger. Milk from milk storage is pumped by a pump ,from pump is passed through flow control valve and then passed through flow meter then entered in a inner side pipe of heatexchanger. Flow of water and milk is countercurrent flow. Due to heat transfer between milk and water ,milk is cooled and water is heated. The function of scrapper in heatexchanger is not allow to stick on the heat transfer surface and provide proper turbulence. And thus improve heat transfer and provide proper cooling of milk. The inlet and outlet temperatures of milk and water are indicated on temperature indicator by sensors are attached at inlets and outlets of heatexchanger.
Abstract: A heatexchanger is an equipment used for transferring heat from one medium to another. There is a wide application of coiled heatexchanger in field of cryogenics and other industrial applications for its enhanced heat transfer characteristics and compact structure. Lots of researches are going on to improve the heat transfer rate of the heatexchanger. Here, We have fabricated the shell and tubeheatexchanger with selecting the materials on the primary objective of enhancing the transfer effectiveness. We casted the tube in the spiral shape with the helical angle of 30 degree. Then we intended to perform calculation on the heat transfer effectiveness. We are intended to show the merits of spiral coiled heatexchanger to that of the conventional parallel type heatexchanger.
simulation can be used to answer questions like: What is the best design for a new network? What are the associated resource requirements? How will a telecommunication network perform when the traffic load increases by 50%? How will new routing algorithm affect its performance? Which network protocol optimizes network performance? What will be the impact of a link failure? The subject of this tutorial is discrete event simulation in which the central assumption is that the system changes instantaneously in response to certain discrete events. For instance, in an M/M/1 queue - a single server queuing process in which time between arrivals and service time are exponential - an arrival causes the system to change instantaneously. On the other hand, continuous simulators, like flight simulators and weather simulators, attempt to quantify the changes in a system continuously over time in response to controls. Discrete event simulation is less detailed (coarser in its smallest time unit) than continuous simulation but it is much simpler to implement, and hence, is used in a wide variety of situations illustrated in fig 2-5.
Abstract— A heatexchanger is a device, which transfer internal thermal energy between two or more fluids at different temperature. Without this essential piece of equipment most industrial process would be impossible. Heat exchangers are widely used in refrigeration air conditioning, and chemical plants. They can be employed in various uses, for instance, to effectively transmit heat from one fluid to the other. Shell-and-tubeheat exchangers (STHXs) are widely applied in various industrial fields such as petroleum refining, power generation and chemical process, etc. Tremendous efforts have been made to improve the performances on the tube side.In this project experimental performance is done on the fixed designed STHX and calculate the heat transfer coefficient and effectiveness. Validation is to be carried out using which gives the result comparison with that of experimental result.Here flow parameters are not varied but size and number of tubes are varied and best efficient model is selected as Optimized value. 3 different number of tubes are used with same shell size remaining same. 40 tubes , 32 tubes and 36 tubes were tried . It's been observed for same input temperatures and mass flow rates for three different models one with 36 tubes , 32 tubes model &other with 40 tubes, the temperature variation in 36 tubes is more and also requires less tubes compared to 40 tube model. so it is more effective than tubes model.