Pdf shell and tube heat exchanger performance researchgate. Fast reactor, nuclear reactor, generation iv reactors, gfr, shell and tube. The intensity of secondary flow 1, 2 developed in the tube is the function of tube diameter d and coil diameter d. A heat exchanger is a system used to transfer heat between two or more fluids. Agrawal department of mechanical engineering, clemson university, clemson, sc, usa subrata sengupta college of engineering, university of michigan, dearborn, mi, usa laminar forced convection in a doublepipe heat exchanger is studied numerically. U tube heat exchanger is a kind of tube and shell heat exchanger, belongs to the petroleum and chemical equipments. Heat exchanger application an overview sciencedirect topics. Due to the high heat transfer efficiency of the plates, plate type heat exchangers are usually very small when compared to a tube and shell type heat exchanger with the same heat transfer capacity. Utube shellandtubes heat exchangers front shell unit the front shell is the. The two most common heat exchanger design problems are those of rating and sizing. This unique, compact design prevents thermal fatigue, increases efficiency and reduces the overall size. It is the most common type of heat exchanger in oil refineries and other large chemical processes. As its name implies, this type of heat exchanger consists of a shell a large vessel with a bundle of tubes inside it.
If the flow pattern is more complex such as the case with most shell and tube heat exchangers, then a correction factor term is used and the. A procedures manual was created for the doublepipe heat exchanger. Shell and tube heat exchangers page 4 of 30 mnl 032a issued 29 august 08, prepared by j. Exergy llc, tubeintube heat exchangers consist of two tubes, an inner and an outer coiled together. Due to enhanced heat transfer in helical coiled configuration the study of flow and heat transfer characteristics in the curved tube is of prime important. A heat exchanger is a device that is used to transfer thermal energy enthalpy between two or more fluids, between a solid surface and. Heat transfer equipment powerpoint heat exchanger heat.
Limitations on the heat exchanger length, diameter, weight, andor tube specifications due to site requirements, lifting and servicing capabilities must be all taken into consideration in the design. Counterflow heat exchanger an overview sciencedirect. A heat exchanger is a heat transfer device that exchanges heat between two or more process fluids. Exergy llc, tube in tube heat exchangers consist of two tubes, an inner and an outer coiled together. As you can see, in a 12 heat exchanger, the tube side fluid flows the entire length of the. Heat exchanger can be considered as a system or component.
This means that for an ideal counterflow heat exchanger, in which the heat transfer takes place across an infinitesimal temperature difference i. Counterflow heat exchanger an overview sciencedirect topics. The heat exchange efficiency of the finning depends on good heat conduction across the joint between the fin and tube interfaces. Most shellandtube heat exchangers have multiple passes to enhance the heat transfer. Heat exchangers have widespread industrial and domestic applications. These heat transfer devices are engineered to meet to a wide variety of applications. Fiorentin, et al noise and vibration analysis of a heat exchanger. Heat transfer coefficient versus mass flow rate for both. Pdf heat exchangers are devices used to transfer heat between two or more fluid streams at different temperatures. This type of exchangers consists of tubes which are bent in the form of a u. Local and average heat transfer and pressure drop characteristics of annularly finned tube heat exchangers acrc tr69 for additional information. We already saw that the design of a shell and tube heat exchanger is an iterative process. The tubes may be straight or bent in the shape of a u, called utubes.
The convection and conduction heat flows are parallel to each other and to the surface normal of the boundary surface, and are all perpendicular to the mean fluid flow in the simple case. Bent tube boiler it is a multidrum boiler with the steam drum at top and mud drum at the bottom. An odd number of tube passes is seldom used except the 11 exchanger. The doublepipe heat exchanger is one of the simplest types of heat exchangers. This type of exchangers consists of tubes which are bent in the form. A shell and tube heat exchanger is a class of heat exchanger. A shell and tube heat exchanger is a class of heat exchanger designs. This is due to the larger area the plates provide over tubes. Shelland tube heat exchangers can have multiple passes, such as 11, 12, 14, 16, and 18 exchangers, where the first number denotes the number of the shells and the second number denotes the number of passes. The overall heat transfer coefficient, u, is an approximate value. Unit operations lab heat exchanger 11 heat exchanger heat exchange is an important unit operation that contributes to efficiency and safety of many.
Types of heat exchangers shell and tube, plate type. Here, we analyze the heat transfer in the entire heat exchanger. Combining each of these resistances in series gives. The term heat exchanger applies to all equipment used to transfer heat between two streams. Heat and mass transfer coefficients under frost conditions in. Here is an example of a 12 1 shell pass and 2 tube passes heat exchanger. Figure 1 natural gas prices over the last 6 years in the united states 1 1. The test coil is a finned tube heat exchanger with 1path structure of 2rows and 1stage, and has the dimension of 400 mm.
Comparison of heat transfer characteristics in helical tube heat exchanger and straight tube heat exchanger is carried out using computational method. Technical catalogue section 5 shell and tube models. Often, engineers prefer to use a heat exchanger design software to create a heat exchanger model. If the heat exchanger is located at the inlet or discharge of a blower with a pulsating flow, such as a roots type rotary lobe blower, the heat exchanger must be protected from the pulsation by a chambered silencer. Khalil and others published shell and tube heat exchanger performance find, read and cite all the research you need on researchgate.
A similar analysis can be performed for the convective transfer in hot water. The heat exchanger must be isolated from system vibrations using flexible piping connections and isolation pads on the mounting feet. The modelling focused on two con gurations speci cally. A shell and tube heat exchanger is an indirect contact heat exchanger in which the hot and cold fluid streams do not come in direct contact but the heat transfer occurs through a dividing wall. Agrawal department of mechanical engineering, clemson university, clemson, sc, usa subrata sengupta college of engineering, university of michigan, dearborn, mi, usa laminar forced convection in a. Reason for heat exchangers a heat exchanger is a piece of equipment built for efficient heat transfer from one medium to another hot and cold fluid. Heat exchangers 73 individual thermal resistances of the system. It is the most common type of heat exchanger in oil refineries and other large chemical processes, and is suited for higherpressure applications. Heat exchangers are usually analyzed using either the logarithmic mean temperature difference lmtd or the. The nusselt number is the ratio of convective to conductive heat transfer across a boundary. Chapter 5 heat exchangers faculty of engineering and. For example, for a turbulent flow inside a circular pipe. Comparison of heat transfer between a helical and straight tube heat exchanger39 figure 6.
Available experimental data on heat transfer in tube bundles in crossflow, both inline, and staggered. Variation of shell side nusselt number nu tube with shell side inlet flow. Pdf shell and tube heat exchanger the heat transfer area. How to calculate nusselt number for a laminar flow at shell. Pdf design of shell and tube heat exchanger single phase. In fluid dynamics, the nusselt number nu is the ratio of convective to conductive heat transfer at a boundary in a fluid. The basic component of a heat exchanger can be viewed as a tube with one fluid running through it and another fluid flowing by on the outside. The heat exchanger should cost as little as possible provided that the above criteria are satisfied. However, the term is commonly used to equipment in which two process streams exchange heat with each other. Convection includes both advection fluid motion and diffusion conduction.
The optimum thermal design of a shell and tube heat exchanger involves the. This particular advantage has been grasped for some time by km. Laminar fluid flow and heat transfer in an annulus with an. Tube in tube heat exchangers garden city, new york exergy.
Selecting reliable heat exchanger tube materials factors. In heat exchanger applications, stainless steel finned tubes are often required for the optimum design for a specific application. The fanlimit control will also need to be removed in order to use vd system. Comparison of heat transfer between a helical and straight. The theories of transient heat transfer in doublepipe heat exchangers were explained and followed by literature correlations. U tube heat exchanger is composed of some main components like the tube box, shell, and tube buddle.
A computer program in matlab has been written for shell and tube heat exchanger design. Therefore a plate type heat exchanger, as compared to a similarly sized tube and shell heat exchanger, is capable of transferring much more heat. Visible defects heat exchanger inspection system nushield. The overall heat transfer coefficient, u, is an approximate. As you can see, in a 12 heat exchanger, the tube side fluid flows the entire length of the shell, turns around and flows all the way back. Accelerometer and microphone positions in the heat exchanger. Following figure details the boundary conditions for the heat exchanger. Ravagnani and others published optimal shell and tube heat exchangers. Theory and application two fluids, of different starting. A procedure for use of the equipment and the software was outlined. Shellandtube heat exchangers compact heat exchangers gasketedplate heat exchangers.
E1mnl032a design and rating of shell and tube heat. In this master thesis modelica models for shell and tube heat exchangers was developed. It is active to some degree or another in everything. The conductive component is measured under the same conditions as. Utube design allows for differential thermal expansion between the shell and the tube bundle as well as for individual tubes. Correlations for the heat transfer coefficient nu hlk function flow. Note the location of sheet metal screws, as they will be of use when using the visible defects heat exchanger inspection system. The parametric analysis of these various correlations with specific data is presented in this paper. The heat transfer coefficient for the tube side is expressed as follows. R sekulib university of kentucky introduction a heat exchanger is a device that is used for transfer of thermal energy enthalpy between two or more fluids, between a solid surface and a fluid, or between solid particulates and a. A practical guide for planning, selecting and designing of shell and tube exchangers takes users on a stepbystep guide to the design of heat exchangers in daily practice, showing how to determine the effective driving temperature difference for heat transfer. Heat transfer equipment powerpoint free download as powerpoint presentation. Pdf effectively design shellandtube heat exchangers. Using a small tube diameter makes the heat exchanger both economical.
Results show that the heat transfer characteristics of the helical tube heat exchanger is much better than that of straight tube heat exchanger, with remarkable increase in the heat transfer. A 12 shelland tube heat exchanger is illustrated in figure 5. Flow in a doublepipe heat exchanger can be cocurrent or countercurrent. Due to the high heat transfer efficiency of the plates, plate type heat exchangers are usually very small when compared. Equation is used when simple counter or cocurrent flows exist. Selecting reliable heat exchanger tube materials factors to consider presented at. Heat exchanger a device in which heat is transferred between two fluid streams at different temperatures in a space separated by a solid wall. Hello, i am having some trouble trying to find an equation that would allow me to calculate the nusselt number for a laminar flow on the shell side for a heat exchanger with a tube bundle.
How to calculate nusselt number for a laminar flow at shell side for a posted in process heat transfer. Heat and mass transfer coefficients under frost conditions. Heat transfer equipment for designing of heat exchangers. You can then use this model to simulate the heat exchanger performance and to verify if it will meet your.
Since all heat exchangers considered in this experiment have a single pass for both the hot and cold fluids, the discussion below is limited to singlepass heat exchangers. The change of exergy of the universe is zero, and the process is reversible. Tube failures a number of potential failure mechanisms are possible in power plant heat exchanger tubing. Heat exchanger application an overview sciencedirect. The heat exchanger fin to tube joint is a t joint configuration and from the advantageous characteristics of laser welding previously described in chapter 2 and reference to fig.
Due to the en tubes of a utube heat exchanger contained by a shell cover of a larger larged shell, this construction has the figure 3 are bent in the shape of a. Api power chem 2014 novotel twin waters, sunshine coast, queensland may 27, 2014 presented by. Qualitative dependence of the fluid temperature on position inside a singlepass heat exchanger is shown in fig. The overall heat transfer coefficient u is the sum of several individual resistances. As its name implies, this type of heat exchanger consists of a shell a large pressure vessel with a bundle of tubes inside it. Analysis of longitudinal fin patterns in a concentric. However, the lower cost for the single tubesheet is offset by the additional costs incurred for the bending of the tubes and the somewhat larger shell diameter due to the minimum ubend radius, making the cost of a utube heat exchanger comparable to that of a. How to calculate nusselt number for a laminar flow at. A computer program in matlab has been written for shell and tube heat. There are three different classifications of shell and tube heat exchangers such as parallel flow, cross flow and countercurrent flow. This kind of heat exchanger is named after theushape tube.
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