Numerical study of fluid flow and heat transfer enhancement. The data of table 64 are used for tube banks having 10 or more rows of tubes in the direction of flow. Flow across tube banks transient vs steady state cfd. The 3d turbulent flow in the tube bank region is modeled by k. Average heat transfer coefficient for the entire tube bank zukauskas correlation. Heat transfer u5l7 flow across tube banks 1 youtube.
Tube bundles are a subcomponent in shellandtube heat exchangers, where the flow resembles crossflow at some places, and longitudinal flow elsewhere. In such equipment, one fluid moves through the tubes while the other moves over the tubes in a perpendicular direction. There are 10 tube rows in the flow direction and 7 tubes per row. A naphthalene sublimation technique is employed to obtain the local heat transfer coefficients, and experiments are performed for various tube spacings, tube. Proper orthogonal decomposition pod was employed to filter the original velocity fields to. The heat flux supply to all tubes was in the range 9683630 wm2. Flow through the tubes can be analyzed by considering flow. Two major sources of data on both fluid flow and heat transfer are the delaware group in the usa and the group in the republic of lithuania. Forced convection boundary layer, flow over flat plates, across cylinders, spheres and tube banks 5. This paper present a twophase pressure drop model for a inline tube bundle for airwater mixtures flowing through an idealised shell and tube, inline heat exchanger.
Nonnewtonian, powerlaw, tube bank, cross flow, dummy introduction. Banks, valuation, accounting statements, cash flow to equity, residual income 1. Flow induced vibration in these heat exchangers leads to equipment breakdown and hence expensive repair and process shutdown. The pressure drop in tubetype heat exchanger is related to the drag coefficient according to the following equation. I am trying to simulate flow and heat transfer across a heat sink with pin fins. The external flow of air with the reynolds number, based on the mean free stream air velocity and outer hydraulic of the tube, varied from 527 to 880. One of the most important passive techniques to augment the heat transfer is the use of vortex generators. The total heat transfer rate from the tube bank depends upon the average heat transfer coe. Air at 1 atm and 10 c flows across a bank of tubes 15 rows high and 5 rows deep at a velocity of 7 ms measured at a point in the flow before the air enters the tube bank. Pr the re in this equation is base on the maximum velocity in the tube bank. Heat transfer in flow across a bank of tubes is of particular importance in the design of heat exchangers.
Heat transfer in flow across a bank of tubes is of partic ular importance in the design of heat exchangers. The pressure drop in tube type heat exchanger is related to the drag coefficient according to the following equation. Introduction in building a cash flow model of a bank from the outside, the equity cash flow ecf how to cite this paper. Tube bundles are a subcomponent in shelland tube heat exchangers, where the flow resembles crossflow at some places, and longitudinal flow elsewhere. Convection heat transfer from tube banks in crossflow citeseerx. Particle image velocimetry piv technique was employed to delineate the flow field at reynolds number 2250. The box header consist of tube sheet, top, bottom, and end plates, and a cover plate that may be welded or bolted on. Flow induced vibration, as the name suggests, is the vibration of a structure in this.
A comparison of heat transfer in staggered and inline tube banks with a gasparticle crossflow. For this purpose, a control volume is selected from the fourth row of a tube as a typical cell to study the heat transfer from an inline or staggered arrangement. In the present work, laminar cross flow forced convective heat transfer of nanofluid over tube banks with various geometry under constant wall temperature condition is investigated numerically. Crossflow, staggeredtube heat exchanger analysis for high. I have examined the final electronic copy of this thesis for form and content and recommend that it. The following correlation has been obtained for heat transfer for the flow of water, 0. The work at the university of delaware on overall heat transfer in tube banks has formed the basis for heat exchanger calculations for many years while the recent book by zukauskas et al. For subsequent rows flow depends strongly on the tube bank arrangement. A tube bank usually consists of many rows of tubes in directions both parallel and perpendicular to the. Forced convection heat transfer from ashutosh sadashiva argave. Tube banks are usually arranged in an inline or staggered manner and are characterized by.
Computational fluid dynamics and heat transfer analysis for a. Heat exchangers are found in numerous industrial applications, such as steam generation in a boiler or air cooling in the coil of an air conditioner. The tubes may be arranged in inline or staggered manner as shown in figs. This paper describes the heat transfer enhancement and fluid flow across tube banks heat exchanger by means of vortex generator. Tube banks are commonlyemployed design elements in heat. Flow across banks of tubes zukauskas correlation if n l. Tubes are rolled or welded into the tube sheets of a pair of box headers.
Heat transfer from banks of tubes depends on the flow conditions, tube geometries, and. The twodimensional steady state navierstokes equations and the energy equation governing laminar incompressible flow are solved using a finite volume method for the case of flow across an inline bundle of tube banks. A comparison of heat transfer in staggered and inline tube. Heat transfer and pressure drop performance comparison of. Yovanovich university of waterloo, waterloo, ontario n2l 3g1, canada doi.
I have been trying to model flow across a tube bank. Analytical model for convection heat transfer from tube banks. Heat transfer enhancement and fluid flow across tube banks. General findings for the flow over tube banks recommend that the eminent parameters like the drag forces, local and global nusselt numbers are compara tively indifferent to the real cylinder. Analytical model for convection heat transfer from tube. The model used momentum flux and entrained liquid fraction to predict the acceleration pressure drop. The model predicts the pressure drop well using both accelaration and gravitational pressure drop. In developing these models, it is assumed that the flow is steady, laminar, and fully developed. In considering the different aspects of the urans performance, west 16 examined both twodimensional i. The main objective of this analytical study is to investigate heat transfer from tube banks in crossflow under isothermal boundary condition. We used nanofluid instead of pure fluid,as external cross flow, because of its potential to increase heat transfer of system. When the flow of fluid through the tube banks in the heat exchanger, there is a rise in pressure drop and decrease in heat transfer, to reduce pressure drop and increase heat transfer through the tube banks must consider how to improve and develop the arrangement of tubes. Pdf heat transfer enhancement and fluid flow across tube.
Flow around tubes in the first row of a tube bank corresponds to that for a single cylinder in cross flow. In such cases it is customary to use a tube bundle in which the water is passed through the tubes, while air is passed in cross flow over the tubes. An application of the equity cash flow and the residual income approach in bankfinan. The suitability and accuracy of wall resolved large eddy simulat ion les and unsteady reynolds averaged navier stokes urans approa ches are examined on generic square in line tube banks, wh ere experimental data are limited but available. The effect of the nanofluid on the compact heat exchanger performance was studied and compared to that of a conventional fluid. Forced convection in cross flow of power law fluids over a. Horizontal twophase flow across tube banks sciencedirect. Flowinduced vibration in these heat exchangers leads to equipment breakdown and hence expensive repair and process shutdown. Net free area for air flow through bundles is about 50% of face area.
Reynolds stress averaging method by employing ansys fluent. A naphthalene sublimation technique is employed to obtain the local heat transfer coefficients, and experiments are performed for various tube spacings, tube locations and reynolds numbers. Turbulent flow through a staggered tube bank article pdf available in journal of thermophysics and heat transfer 204. Flow across banks of tubes example pressurized water is often available at elevated temperatures and may be used for space heating or industrial process applications. Assessment of correlations for singlephase heat exchangers. A study on heat transfer characteristics for staggered. Crossflow, staggeredtube heat exchanger analysis for. Hammock entitled crossflow, staggeredtube heat exchanger analysis for high enthalpy flows. Forcedconvection heattransfer correlations for gases. Proper orthogonal decomposition pod was employed to filter the original velocity fields to identify the. The pressure drop across the model2 is less and more linear then model1. From the trailer the gas flowed through a preset pressurereducer valve, a remotely operated control valve, a convergentdivergent flow nozzle, and an onoff valve before it. I am submitting herewith a thesis written by gary l.
Tube bank is the cross flow tubular heat exchanger consists of multiple rows of tubes. This study is one of the first attempts to develop analytical models for the heat transfer from tube banks inline and staggered. I have examined the final electronic copy of this thesis for form and content and recommend that it be accepted in partial fulfillment of the requirements. This test facility allows measurement at reynolds numbers in the range between 4500 and 35000 and flue gas massflow from 0. Cross flow over tube banks is commonly encountered in practice in heat transfer equipments. Pdf a comparison of heat transfer in staggered and inline. Crossflow over tube banks is commonly encountered in practice in heat transfer equipments. A study on heat transfer characteristics for staggered tube. Convection heat transfer from tube banks in crossflow. Previous periodic calculations of in line tube banks afgan, 2 007.
Tube banks are commonlyemployed design elements in heat exchangers. These models are developed in terms of longitudinal and transverse pitches, reynolds and prandtl numbers. Mathcad functions for forced convection heat transfer. For fewer rows the ratio of h for n rows deep to that for 10. Numerical analysis of flow induced vibrations of tubes banks in cross flow using porous media rahul dube1, akhilesh parmar2. Pdf piv measurement of fluid flow through staggered tube. Recently professor hsu, with his graduate students, hsieh. Twophase flow pressure drop model for a shell side of a. Computational fluid dynamics and heat transfer analysis. Heat transfer and fluid flow characteristics study for in. Flow across tube banks the experimental results for the flow across tube banks are represented in the form of nu c. The normal resolutes are required to compute the flux of across a. An experimental investigation was performed on fluid flow through staggered tube arrays by varying tube spacing centertocenter distance of cylinders ld 3.