Baffle Angle Research Articles

An Investigation of baffle angles on Shell and Tube heat exchanger

The turn of events and execution enhancement of shell and tube heat exchanger is an issue of incredible test and part of arising early innovation. The exhibition enhancement would serve an extraordinary commitment to assuage the swelled working expenses just as energy emergency. This paper grandstands every one of the experimental outcomes got from the constant framework investigation in different working conditions. Further it addresses examination for a few shell-and-tube heat exchangers with segmental confounds with various point parametric variety. The framework distinguishing proof has been done utilizing CFD investigation. The consolidated outcomes as for same shell-side stream rate show that, the heat move co-proficient of the heat exchanger with astounds is higher than that of the heat exchanger without perplexes, while the shell-side pressing factor drop of the previous is even a lot of lower than that of the last mentioned. Further upgrade methods ought to be consolidated to improve shell-side heat move dependent on a similar stream rate. The near investigation of heat move coefficient per unit pressure drop shows that the Segmental Baffle Heat exchanger have critical execution advantage over Segmental Baffle Heat exchanger for similar mathematical arrangements.

CFD Analysis and Taguchi-Based Optimization of the Thermohydraulic Performance of a Solar Air Heater Duct Baffled on a Back Plate

In this paper, a solar air collector duct equipped with baffles on a back plate was numerically investigated. The Reynolds number (Re) was varied from 5000 to 20,000, the angle baffle (a) from 30° to 120°, the baffle spacing ratio (Pr) from 2 to 8, and the baffle blockage ratio (Br) from 0.375 to 0.75 to examine their effects on the Nusselt number (Nu), the friction factor (f), and the thermohydraulic performance parameter (η). The 2D numerical simulation used the standard k-ε turbulence model with enhanced wall treatment. The Taguchi method was used to design the experiment, generating an orthogonal array consisting of four factors each at four levels. The optimization results from the Taguchi method and CFD analysis showed that the optimal geometry of a = 90°, Pr = 6, and Br = 0.375 achieved the maximum η. The influence of Br on all investigated parameters was considerable because as Br increased, a larger primary vortex region was formed downstream of the baffle. At Re = 5000 and the optimal geometry parameters, a maximum η of 1.01 was reached. A baffle angle between 60° and 90° achieved a high Nusselt number due to the impingement heat transfer.

Numerical investigation of the impact of inclined baffles and an elastic vibrating beam on the thermo-fluid behavior in a rectangular channel

In the present work, the influence of inclined baffles and an elastic vibrating beam is investigated on the flow pattern and heat transfer rate in a rectangular channel. The cylinder with the elastic vibrating beam develops the vibrating flow. The computations are based on the finite element method (FEM); Galerkin least-squares scheme and Newton–Raphson iterative method are implemented to solve the governing equations. The fluid structure-interaction (FSI) method is used to analyze the elastic vibrating beam. The friction factor coefficient and Nusselt number are examined for the inclined and conventional baffles. The flow regime is assumed to be laminar for various baffle angles and Reynolds numbers. The vibrating beam is connected to the cylinder located in the channel entrance. Optimized cases with the maximum heat transfer and minimum friction factor are introduced. The novelty of this study is the simultaneous use of the elastic vibrating beam and inclined baffles in a rectangular channel. The results show that mounting an elastic vibrating beam on the cylinder leads the heat transfer rate to increase. The channel with an elastic vibrating beam and inclined baffles at 135° is the optimized case compared to other cases.Article HighlightsTake advantage of using an elastic vibrating beam in a rectangular channel.Influences of inclined baffles on thermal performance are examined numerically.The optimum case for the channel with inclined-baffles is reported.

Combination Effect of Baffle Arrangement and Hybrid Nanofluid on Thermal Performance of a Shell and Tube Heat Exchanger Using 3-D Homogeneous Mixture Model

In this study, thermal performance and flow characteristics of a shell and tube heat exchanger equipped with various baffle angles were studied. The heat exchanger was operated with distilled water, and a hybrid nanofluid at three concentrations of 0.04% and 0.10% of GNP-Ag/water within Reynolds numbers ranged between 10,000 and 20,000. The thermophysical properties of nanofluid varied with temperature and nanoparticles’ concentration. The baffle angles were set at 45°, 90°, 135°, and 180°. Results showed that the calculated Nusselt number (Nu) could be improved by adding nanoparticles to the distilled water or increasing the fluid’s Reynolds number. At a low Re number, the Nu corresponding to baffle angle of 135° was very close to that recorded for the angle of 180°. At Re = 20,000, the Nu number was the highest (by 35% compared to the reference case), belonging to a baffle angle of 135°. Additionally, results related to friction factor and pressure drop showed that more locations with fluid blocking were observed by increasing the baffle angle, resulting in increased pressure drop value and friction. Finally, the temperature streamlines counter showed that the best baffle angle could be 135° in which maximum heat removal and the best thermal performance can be observed.

Micromixer structure design based on Koch fractal principle and baffle distribution on the lower surface

In this paper, the effect of the baffle on the mixing efficiency is studied when the baffle is distributed on the lower surface of the microchannel. The mixing efficiency of the micromixer was analyzed by numerical simulation. To study the change of mixing efficiency of micromixer, we changed the fractal number of baffles, height of baffles, spacing of baffles, angle of baffles, the number of baffles. Through analysis and comparison, we finally chose a micromixer with fractal number of 2, baffle height of 0.2 mm, baffle spacing of 0.25 mm, baffle angle of 45° and baffle number of 15.

Heat and Fluid Flow Characteristics of Nanofluid in A Channel Baffled Opposite to The Heated Wall

In this paper, a nanofluid-based solar collector duct equipped with baffles is examined numerically. Baffles are located on the back plate to guide nanofluid flow toward absorber plate for heat transfer enhancement purposes. Cu-water nanofluid with fixed flow rate and concentration in the baffled duct are investigated for thermohydraulic mechanisms. Baffles with different inclination angles, heights and pitches are considered in this study. Numerical simulations are performed using Ansys fluent software with verified results compared to those of an experiment in the literature. The results show that the baffle angle 60° causes the lowest thermohydraulic performance. Because in the angle range of 30 to 60° the heat transfer is less variable while the pressure loss increases sharply. At the baffle pitch of 40 mm, there is no reattachment point at the non-heated surface. At the angle of 90°, three eddies are formed around a baffle. The slope linear regression analysis yields that baffle height has the strongest effects on thermohydraulic performance followed by baffle pitch and baffle angle. Nanofluid pressure loss respectively increases with baffle height and baffle angle at the rate of 0.463675 and 0.0049607 while absorber plate temperature respectively decreases with the baffle height and baffle angle at the rate of -0.176746 and -0.001377. Flow patterns and isotherms of all the cases examined are presented and analyzed in this study.

Numerical simulation and experimental investigation of gas-liquid two-phase flow in a complex microchannel

The present investigation evaluated a microchannel with variable cross sections and internal elements by experimental and numerical methods. The numerical and experimental phase interface of gas-liquid two-phase flow is captured through the Coupled Level-Set and Volume-Of-Fraction (CLSVOF) method and the canny edge detection method, respectively. The microchannel is analysed with different baffle angles (bending angle of the baffle, BA), and the optimal BA is chosen. The optimization goal is to increase the area of high-shear region and reduce the area of other region. Experiments involving the microchannel with optimal 67.5° BA are conducted. The experimental results confirm the microchannel mixing potency that the optimal structure of the high-shear region accelerates the fluid velocity, amplifies disturbances resulting from the merging of different gas phases and promotes the expansion of the turbulent domain.

Shape optimization of segmental porous baffles for enhanced thermo-hydraulic performance of shell-and-tube heat exchanger

This study presents the development and evaluation of a novel shell-and-tube heat exchanger (STHX) design with segmental porous baffles. Computational fluid dynamics (CFD) in combination with machine learning tools are utilized to investigate the thermo-hydraulic impacts of segmental porous baffles on shell side flow of a STHX. Three geometric parameters (number of baffles, baffle angle, and baffle thickness) of these baffles, which are placed inside the STHX, are selected to perform the parametric study and multi-objective optimization. Higher number of baffles are beneficial to increase the rate of heat exchange; however, it would escalate the pressure drop considerably. Results also show that baffles angle plays a critical role on the performance of a STHX. An artificial neural network (ANN) is trained to predict the system’s performance. As lowering the pressure drop and increasing the heat transfer are the two main objectives in STHX, a multi-objective optimization study is conducted. Different decision-making algorithms are also applied to find the best alternative among the Pareto frontier points. Results of optimization show that a STHX with 10 porous baffles, baffle angle of 111.9, and baffle thickness of 16.69 mm would be the best geometrical configuration which results in a heat transfer rate of 523.81 kW while the pressure drop of the shell side flow would be 48.87 kPa. With this novel design, it is also possible to improve both pressure drop and heat transfer rate of STHX, simultaneously. A particular configuration of the introduced STHX could reduce the pressure drop by 61.3% while heat transfer enhances by 11.15% simultaneously.

A Simple Device for Barnyard Seeds Purification to Use It As Feeder for Small Birds جهاز بسیط لتنقیة حبوب الدنیبة لإستخدامها کغذاء للطیور الصغیرة

A portable apparatus for separating the expended husks from bird seed mixtures after the bird has shelled the seeds and left the husks among the seeds has been designed. It includes a hopper, rectangular case divided in two parts (one for receiving seeds and other collecting un-seed materials) and air supply means. The air stream agitates the mixture and floats the husks and fine dust up wardly for collection in the husk receiver while the air exhausts through holes at the opposite side. The experiments included four cleaning air speeds (2.5, 3.0, 3.5 and 4.0 m/s), four baffle angles (35, 40, 45 and 50°), two fiberglass baffles (with or without rubber covered) and two seed samples (before and after feeding). Cleaning efficiency and seed losses were measured. Results showed that, the maximum value of cleaning efficiency (98.7 %) for seed mixture before feeding was achieved at cleaning air speed of 4.0 m/s, baffle angle of 35° and baffle without rubber. The minimum value of seed losses (0.3 %) for seed mixture after feeding was achieved at cleaning air speed of 2.5 m/s, baffle angle of 50° and baffle with rubber. It is recommended to use the cleaning device at cleaning air speed of 4.0 m/s, baffle angle of 35°, baffle without rubber to increase the cleaning efficiency and use it at cleaning air speed of 2.5 m/s, baffle angle of 50°, baffle with rubber to lessen seed losses.

Thermohydraulic correlations and exergy analysis of a solar air heater duct with inclined baffles

This paper presents the development of the Nusselt number and friction factor correlations of a solar air collector with inclined baffles on the basis of experimental data. An evaluation of the exergy performance of the collector is conducted. The inclination angle of the baffle studied ranges from 0° to 180°. The baffle pitch and size of the solar air heater duct are fixed in the current work. The maximum errors between the predictions of the correlations and the experimental data are 6% for the Nusselt number and 8.3% for the friction factor. The exergy efficiency analysis shows that the largest collector efficiency of 0.7% is reached at a baffle angle of 60° and a Reynolds number of 1500. A baffle angle of 60° causes the highest turbulence due to an increased degree of blockage. Furthermore, the baffle angle results in a smaller friction factor than the others, e.g. 45° and 120°. The thermal efficiency, effective efficiency and exergy efficiency of the collector with baffle angles of 30° and 150° are nearly equal. A baffle angle of 0° indicates the lowest efficiency. Overall, it is suggested that baffle angles from 60° to 120° should be selected to obtain high efficiencies.

Numerical investigations of fluid flow and heat transfer characteristics in solar air collector with curved perforated baffles

AbstractIn this article, an improved double‐pass solar air heater with multiple curved perforated baffles is proposed; the solar air heater can enhance the heat transfer between air and heat absorber plate sufficiently by using a perforated baffles. At the same time, to reduce the flow resistance of air, a curved shape was created on the baffles. This research is aimed at evaluating a novel solar air heater design in terms of its thermal efficiency and temperature distributions within the solar air heater in forced convection. This investigation is performed based on numerical simulations in two‐dimensional, steady, incompressible Navier‐Stokes and energy equations utilizing CFDRC software with the shear stress transport turbulence model. The main factors including the hole diameter, baffle inclination angle, and air mass flow rate were evaluated. The effects of these factors on the thermal efficiency of solar air heater and the temperature and pressure difference between the inlet and outlet were analyzed. The results obtained for the different cases show that the maximum thermal efficiency of the air heater is about 77% at air mass flow rate = 0.03 kg/s, hole diameter = 3 mm, and baffle angle = 7°. However, the work section pressure drop across this new solar air heater is varied between about 15.05 and 1.7 N/m2. These numerical results are important for the application of this improved solar air heater and show that the curved perforated baffles in the air channel is a crucial factor for improving of collector performance.

Thermohydraulic performance study of different square baffle angles in cross-corrugated channel

Cross-corrugated channels implementing high heat transfer performance are proper to employ in plate fin heat exchangers. In this work, the heat transfer, pressure drop and thermohydraulic performance in the cross-corrugated triangular channels having rectangle baffles with different settlement angles are numerically researched. Ansys-Fluent program is performed to solve Navier Stokes and energy equations by using k-ε turbulence model in numerical calculations. While air inlet temperature employed as working fluid is 293 K, wall surface temperature values of the lower corrugated duct are taken as constant 373 K. The constant rectangle baffle height and apex angle of the corrugated channel are utilized as 0.5 H and 60°, respectively. Re number range analyzed in this work is 1000–6000 while the rectangle baffle settlement angles are 30°,45°,60° and 90°. Numerical results are agreed with 3.53% deviation according to experimental study existed in literature. The attained results are exhibited as mean Nu number, fluid temperature and pressure variations for each rectangle baffle angle. Contour distributions of the temperature and velocity vector are also evaluated for different Re numbers and rectangle baffle angles. The Num value for the corrugated channel with rectangle baffle of 90° angle is 52.8% higher than that of the 60° for the Re = 6000. Also, for Re = 1000 the value of the pressure drop is 65.97% lower in the corrugated triangular channel with 60° rectangle baffle angle than that of 90° angle.

Heat transfer and pressure drop evaluation of different triangular baffle placement angles in cross-corrugated triangular channels

Plate heat exchangers have a widespread usage and the simplest parallel plate channel structures. Cross-corrugated ducts are basic channel geometries used in the plate heat exchangers. In this study, the increasing of heat transfer from the cross-corrugated triangular ducts by inserting triangular baffles with different placement angles into the channel upper side and pressure drop have been numerically investigated. Numerical calculations have been carried out to solve Navier-Stokes and energy equations by employing k-? turbulence model as 3-D and steady with ANSYS-FLUENT program. While inlet temperature of the air used as working fluid is 293 K, constant surface temperature values of the the lower corrugated channel walls are 373 K. The height of the baffle and apex angle of the corrugated duct have been taken constant as 0.5 H and 60?, respectively. Investigated Reynolds number range is 1000-6000 while the baffle placement angles are 30?, 45?, 60?, and 90?. Numerical results of this study are within 3.53% deviation with experimental study existed in literature. The obtained results have been presented as mean Nusselt number temperature and pressure variations of the fluid for each baffle angle. The temperature and velocity vector contour distributions have been also assessed for different Reynolds numbers and baffle angles. The value of the Num for the corrugated channel with 60? baffle angle is 8.2% higher than that of the 90? for the Re = 4000. Besides, for Re = 1000 the value of the pressure drop is 39% lower in the channel with 60? baffle angle than that of 90?.

Passive micromixer with baffles distributed on both sides of microchannels based on the Koch fractal principle

AbstractSince the beginning of the 21st Century, the development of microfluidic chip technology has been very rapid and has attracted the attention of more and more scholars. As an important part of the microfluidic chip, the performance of the micromixer is critical. The fractal structure in the microchannels helps to improve the mixing performance of the micromixer and improve the mixing efficiency of the micromixer. The research results of other scholars are of great significance to the research of the present paper, which mainly studies the effect of changing the baffle state on the mixing efficiency of the micromixer based on the Koch fractal principle. Through simulation analysis, it was found that the mixing efficiency of the baffles distributed on both sides of the microchannel was higher than the mixing efficiency of the baffles distributed on the microchannel side. When the distance between adjacent baffles was divided into 0.15, 0.25 and 0.35 mm, simulated data suggested that the baffle distance of 0.15 mm was best. Increasing the number of baffles from six to eight groups increased the mixing path of the fluid in the microchannel and improved mixing efficiency. A comparison of mixing efficiencies of the 0°, 15° and 30° baffle angles revealed that very significant improvement in mixing efficiency was obtained at 30°. © 2019 Society of Chemical Industry

Analyze The Effects of Helical Baffles Angles Variation On Shell Side Heat Transfer Coefficient And Pressure Drop of Shell And Tube Heat Exchange

E-201-11 is one of the components of heat exchanger which serves to increase the temperature of distillated crude oil before it going into the furnace. The use of segmental baffles on the heat exchanger causes dead zone. The fouling phenomenon that arises from the deposition of the compound content in the service fluid in dead zone can result in leakage of the shell and tube. It affects the performance of heat exchanger and production efficiency. The use of discontinuous helical baffle on the shell side minimizes fouling. Research on the variation of helical baffle angle by using Bell-Delaware method resulted in performance value of heat transfer coefficient and pressure drop on the shell side. Fluid flow behavior on the shell side with helical baffle was analyzed by Computational Fluid Dynamics (CFD). The fluid flow velocity is a factor that affects the value of heat transfer coefficient and pressure drop. Heat exchanger with an angle of 10º have fluid flow velocity of 0,893m/s resulting in the highest heat transfer coefficient and pressure drop value compared to angles of 15º and 20º with values of 585.725W/m²K and 13642.395Pa. The heat exchanger with helical baffle at 10° helix angle presents the best performance among the others variant helical baffles

Thermo-Hydraulic Performance Evaluation of Shell & Tube Heat Exchanger with Different Tube Geometries

A heat exchanger is equipment that transfers heat energy from one fluid stream to another fluid stream across a solid surface by conduction and convection. Heat exchangers are used in air conditioning & refrigeration systems, power plants, automotive industries, chemical processing, waste heat recovery systems, and food industries. Shell & tube heat exchangers are the most widely used heat exchanger. Earlier many types of studies were carried out on baffle of heat exchanger, as the hydraulic performance of shell side of exchanger relies on baffle elements such as changing baffle types, baffle segments, baffle angles, baffle cuts, etc. are introduced. But only a few researches are concentrated on the tube side. In this paper, efforts have been made to design a shell & tube heat exchanger by using the kern method & referring TEMA standards. Also, the fluid flow behavior & heat transfer mechanism of shell & tube heat exchanger with four different cross-sections of the tubes i.e. Circular, Rectangular, Square & Triangular is numerically investigated using ANSYS-fluent. Numerical simulation was carried out for a single tube pass shell & tube heat exchanger with 25% baffle cut. Finally, from the simulation results, suggestions are made for the best geometry which gives the best thermo-hydraulic performance.

Shaking table tests on a SDOF structure with cylindrical and rectangular TLDs having rotatable baffles

Control of vibrations against extraordinary excitations such as wind and earthquake is very important to the protection of life and financial concerns. One of the methods of structural control is to use Tuned Liquid Damper (TLD), however due to the nature of TLD only one sloshing frequency can be created when the water is sloshing. Among various ideas proposed to compensate this problem, by changing the angle of some rotatable baffles embedded inside a TLD, a frequency range is created such that these baffles are tuned manually at different frequencies. In this study, the effect of cross sectional shape of container with rotating baffles on seismic behavior of TLD is experimentally studied. For this purpose, rectangular and cylindrical containers are designed and used to suppress the vibrations of a Single Degree-Of-Freedom (SDOF) structure under harmonic and earthquake excitations considering three baffle angles. The results show that the rectangular-shaped damper reduces the structural response in all load cases more than the damper with a cylindrical shape, such that maximum differences of two dampers to reduce the structural displacement and structural acceleration are 5.5% and 3% respectively, when compared to the cases where no baffles are employed.

Thermal-Hydraulic Characteristics of Helical Baffle Shell-and-Tube Heat Exchangers

Shell-and-tube heat exchangers are frequently used in several industrial applications. A model was developed using engineering equations solver software to predict the performance of various baffle configurations of shell-and-tube heat exchangers. The model is based on the Bell-Delaware method for the segmental baffle, while mathematical correlations for the helical baffle are provided for design and analysis purpose. The accuracy of the present model is validated against the experimental data available in the literature. The results showed that helical baffles offer much higher performance compared to the segmental baffled heat exchanger. It was found that the performance of the helical baffle increases with increasing baffle angle until it reaches an optimum value; it then starts to decrease at an angle of 42°.

Numerical simulation and optimization of the flash chamber for multi-stage flash seawater desalination

In this paper, a mathematical model of multi-stage flash (MSF) chamber was proposed. The volume of fluid (VOF) multiphase model was modified by adding the quality source term, the component source term and the energy source term in the governing equation through the user defined function (UDF) program. The Fluent software was adopted to solve the proposed model. By analyzing the vapor-liquid flow nephogram of velocity vector and mass fraction inside the flash chamber, the relations between the vaporization rate and the structure of the flash chamber were explained. Two approaches for enhancing the flash efficiency were suggested, i.e., increase the spoiler to prevent liquid from flowing directly into the next stage through the bottom outlet and, change the vertical baffle angle to reduce the flow dead zone in the low pressure chamber. Based on this, five improved flash chamber structures were proposed. Simulation results showed that the flash efficiency can be significantly increased by adding the baffle and/or by changing the angle of the vertical baffle. The flash rate of Model-4 and Model-6 are higher than others. In the MSF seawater desalination process, Model-6 is suitable for low concentration stages, while Model-4 is ideal for high concentration stages.

Experimental and Numerical study of Mixed Convection in a Partially Opened Cavity with Tilted Baffle

In this study the mixed convection heat transfer process in a square cross section cavity with a bottom groove heated from three side walls (left, right, and bottom) with vertically unheated baffle is investigated numerically and experimentally. In the numerical part the in-house CFD commercial code of ANSYS-FLUENT-V.16.0 based on finite volume method has been used to solve the 2D governing equations. The results are represented in terms of wall temperature profiles and Nusselt numbers of the heated wall. For the experimental work, a test rig were built to determine the effect of heater position, baffle height ratio (h/H), the baffle angle for the range of 300 <Re <1000 and 1 <Ri< 700. The experimental results show a good enhancement about (35 %) in heat transfer can be obtained by using the baffle while the maximum values was by using right heater and with baffle angle 90o. The numerical flow visualization gives a good indication to temperature boundary layer and vortices location of flow. Good agreement was observed when comparing the experimental and numerical work and with other pervious work.