Effect Of Baffle Spacing Research Articles

Experimental investigations on thermo-fluid performance of perforated baffle aided with oppositely oriented sawtooth deflector in tubular heat exchanger

Purpose The investigation concentrated on studying a distinct category of tubular heat exchanger that uses swirling airflow over tube bundle maintained at constant heat flux. Swirl flow is achieved using a novel perforated baffle plate with rectangular openings and multiple adjustable opposite-oriented saw-tooth flow deflectors. These deflectors were strategically placed at the inlet of the heat exchanger to create a swirling flow downstream. Design/methodology/approach The custom-built axial flow heat exchanger consists of three baffle plates arranged longitudinally supporting tube bundle maintained at constant heat flux. The baffle plate equipped with saw-tooth flow deflector of various geometry represented by space height ratio(e/h). Next, ambient air was then directed over the tube bundle at varying Reynolds number and the effect of baffle spacing (PR), Space height ratio (e/h) and inclination angle(a) of deflectors on performance of heat exchanger was experimentally analyzed. Findings The heat transfer augmentation of heat exchanger for given operating condition is strongly dependent on geometry, inclination angle of deflector and baffle spacing. Originality/value An average improvement of 1.42 times in thermal enhancement factor was observed with inclination angle of 30°, space height ratio of 0.4 and a pitch ratio of 1.2 when compared to a heat exchanger without a baffle plate under similar operating conditions.

Parametric & CFD Analysis of Shell and Tube Heat Exchanger by Varying Baffles Geometry

The Shell and Tube Heat Exchanger are most commonly used in current industrial production. In this study, the effect of baffle spacing on pressure drop and heat transfer coefficient are considered in a shell and tube heat exchanger with single segmental baffles and staggered tube layout. The effects of number of baffles are considered 4, 6, 8, 10, 12, and 14 and baffle spacing are considered 366.67, 220,157.14, 122.22, 100, and 84.61 respectively with 38% baffle cut are investigated to study the effect of pressure drop and heat transfer coefficient.Shell and tube heat exchanger with single segmental baffles is designed with same input parameters using Kern’s theoretical method and Bell-Delaware method. From the CFD simulation results, heat transfer coefficient and pressure drop values for varying tube layout are provided.Variation of number of baffles with shell side pressure drop heat transfer coefficient are shown. It is discussed that for both methods (analytical calculation and CFD result) pressure drops will be increases with increases number of baffles. K- Standard turbulence model with second order discretization and fine mesh is selected for CFD simulation considered.The result are shown highly sensitive to tube layout orientation selection, it is observed for this heat exchanger geometry 30 tube layout and 14 baffle arrangement gives slightly better results. Keywords : CFD Ansys simulation, Heat transfer coefficient, Pressure drop DOI: 10.7176/IEL/10-3-03 Publication date: November 30 th 2020

Performance analysis of shell and tube heat exchanger: Parametric study

Enhancement of heat transfer through shell and tube exchangers stills taking high attention by researchers. The present work investigated the effect of shell diameter and tube length on heat transfer coefficient and pressure drop for shell side with both triangular and square pitches. In addition, the effect of baffle spacing and cutting space on heat transfer coefficient and pressure drop were studied. Moreover, standards fouling rates used for both shell and tube sides to estimate the reduced heat transfer. Increasing shell diameter with a triangular pitch and pull-through floating head recorded 3% increasing in heat transfer coefficient for only 0,05 m increasing in shell diameter. While 2.8% increase in heat transfer coefficient for shell side by 0.05 m increasing in shell diameter with split-ring floating head and square pitch. Heat transfer coefficient for shell side reduced by 15.15% by increasing baffle space by 0.2 from shell diameter and the pressure drop by 41.25%. Increasing cutting space from 15% to 25% decreases heat transfer coefficient by 5.56% and the pressure drop diminished by 26.3%. Increasing tube length by 0.61 m leads to enhance the heat transfer coefficient by 31.9% and pressure drop by 14.11% for tube side. For shell side, increasing tube length by 0.61 m gives 2.2% increasing in heat transfer coefficient and 21.9% increasing for pressure drop. Fouling resistance change on shell side shows a high effect on heat transfer more than same rate change on the tube side. Based on the result, this study can help designers to quick understand of each parameter effect on heat transfer into shell and tube exchangers.

Effect of baffle spacing and baffle cut on thermal-hydraulic characteristics of the fluid flow

This article presents the results of investigations of the influence of baffle spacing and baffle cut on the size of dead zone formed near the cross baffles using numerical simulation methods. It is showed the structure of an additional baffle plate which can be used to reduce the dead zone and smoother flow distribution over the cross section.

The effect of baffle spacing on hydrodynamics and solute transport in serpentine contact tanks

"The effect of baffle spacing on hydrodynamics and solute transport in serpentine contact tanks." Journal of Hydraulic Research, 52(1), pp. 152–154

Closure to “The effect of baffle spacing on hydrodynamics and solute transport in serpentine contact tanks“

"Closure to “The effect of baffle spacing on hydrodynamics and solute transport in serpentine contact tanks“." Journal of Hydraulic Research, 52(1), p. 154

The effect of baffle spacing on hydrodynamics and solute transport in serpentine contact tanks

The effect of baffle spacing on the hydrodynamics and transport characteristics in a scaled variable-baffle-spacing contact tank is investigated by employing large-eddy simulation. Simulated solute transport is quantitatively validated by comparing simulated and measured residence time distribution curves, for which good agreement is found. The flow in serpentine disinfection tanks is dominated by a path of high streamwise velocities, a so-called short-circuiting path, which is almost constant in width regardless of the baffle spacing. In addition, large-scale turbulent vortices are shed from baffle edges and their size and dynamics depend on the spacing between subsequent baffles. The transport in serpentine-flow contact tanks is advection dominated and transport occurs mainly along the short-circuiting path. Wider compartments feature large recirculation zones with instantaneous vortices entraining solutes into these zones and thereby increasing residence times. Contact tanks with wide compartments suffer from severe short-circuiting and internal recirculation. This is directly reflected in hydraulic efficiency indicators.

Effect of baffle spacing on pressure drop and local heat transfer in shell-and-tube heat exchangers for staggered tube arrangement

Local heat transfer and pressure drop on the shell side of shell-and-tube heat exchangers with segmental baffles were investigated for different baffle spacings. The distributions of the local heat transfer coefficients on each tube surface within a fully developed baffle compartment were determined and visualized by means of mass transfer measurements. Per-tube, per-row and per-compartment average heat transfer coefficients were drawn from the local values. The local pressure measurements allow the determination of the shell-side flow distributions. For same Reynolds number, the pressure drop and average heat transfer are increased by an increased baffle spacing due to a reduced leakage through the baffle-shell clearance. The experimental results were compared with literature values.

The effect of baffle spacing on the dynamics of shell and tube heat exchangers

AbstractThis note reports on some aspects of the effect of shell side baffle geometry on the dynamic behaviour of flow forced shell and tube heat exchangers. Frequency response data for four heat exchangers with different baffle geometry were obtained. A second order critically damped transfer function gave an adequate description of the dynamic behaviour. The apparent natural frequency is a function of the shell‐side and tube‐side flow rates and fluid properties, as conveniently expressed by the overall heat transfer coefficient; and of the size and shape of the baffle compartments, as expressed by the ratio of shell diameter to baffle spacing.