Helical Baffles Research Articles

Heat Transfer Performance and Flow Characteristics of Helical Baffle–Corrugated Tube Heat Exchanger

Heat Transfer Performance and Flow Characteristics of Helical Baffle–Corrugated Tube Heat Exchanger

Reviewing the Impact of Helical Baffles on Heat Exchanger Performance

Reviewing the Impact of Helical Baffles on Heat Exchanger Performance

Thermal energy transfer for green urban development: numerical investigation on the heat transfer and flow noise in heat exchangers with different helical and segmental baffles

Thermal energy transfer for green urban development: numerical investigation on the heat transfer and flow noise in heat exchangers with different helical and segmental baffles

Numerical evaluation of thermohydraulic parameters for diverse configurations of shell-and-tube heat exchanger

This research aims to optimize the internal design of shell-and-tube heat exchangers by investigating the thermal performance of various configurations. A comparative study of segmental baffles with plain and finned tube setups and helical baffles with different angular orientations is conducted using numerical simulations with the Galerkin finite element analysis. Key thermohydraulic parameters, such as shell-side pressure difference, heat transport coefficient, and heat transport coefficient per unit pressure drop, are assessed with shell-side mass flow rates. The outcomes direct higher shell-side oil mass flow rates correlate with increased pressure drop and enhanced heat transfer coefficients. Helical baffles exhibit superior performance to segmental baffles, offering a more significant heat transport coefficient per unit pressure drop. Within segmental baffles, finned tubes lead to higher pressure drops and heat transport coefficients than plain tubes while maintaining similar heat transport coefficients per unit pressure drop. Furthermore, lower helix angles (Φ = 10.81°) in helical baffles are associated with higher pressure drops and heat transport coefficients, whereas Φ = 25.52° achieves the highest heat transport coefficient per unit pressure drop.

Modelling and optimising of MED-TVC seawater desalination plants assisted with electric heaters

One major issue with MED-TVC systems, a widely used thermal-based desalination technology, is their high energy consumption and carbon emissions. This underscores the importance of optimising and integrating these thermal-based desalination technologies with sustainable energy systems to utilize their waste heat and enhance the performance of these plants effectively. This research aimed to optimize and address the environmental challenges of MED-TVC desalination plants in areas with insufficient sunlight, unstable weather conditions, and limited economic resources. To this end, a model of an electric heater for generating thermal energy coupled with an optimized MED-TVC desalination plant was proposed. The MED-TVC section was optimized by incorporating an additional ejector in the final stage of MED-TVC demonstrating an increase of over 11 % in evacuating non-condensable gases from the last effect and increasing the product water by up to 14.89 %. Regarding the design of the electric heating elements used in electric heaters, the use of one-plus-two U-tubes with helical baffles was more efficient than multi-layer U-tubes with segmental baffles as improved the pressure loss of the thermal fluid by 25 % and increased the heat transfer coefficient of the heating elements to 18 %. The power section was also equipped with an off-grid system to provide the necessary power for the equipment of the proposed model. In the economic analysis of employing a parabolic trough solar collector and electric heaters, not only were the direct costs of the electric heaters almost equal to just 40 % of the direct costs of the parabolic trough solar collector approach but also the required thermal fluid was 50 % of the solar case.

Comprehensive numerical investigation of the effect of various baffle design and baffle spacing on a shell and tube heat exchanger

This article explores the significance of Shell and Tube Heat Exchangers (STHX), with a focus on various baffle types such as Segmental, Double segmental, Helical, Disc-and-Doughnut, Clamping anti-vibration, and Flower-B. In this study, the commercial software ANSYS FLUENT is used to simulate the problem. The study evaluates their impact on heat exchanger performance using parameters like overall heat transfer coefficient (OHT), pressure drop (PD), and Performance Evaluation Criteria (PEC). Clamping anti-vibration, Flower-B, Helical, and Double segmental baffles exhibit reductions in shell side PD by 14%-28%. Despite OHT reductions in these designs, Disc-and-Doughnut baffles demonstrate a higher OHT (21%-24%) compared to Segmental baffles. Based on PEC values, Disc-and-Doughnut baffles are identified as the most favorable. Further investigation into different numbers of Disc-and-Doughnut baffles reveals increased OHT (17%-29%), PD (58%-59%), and cold water temperature (0.5%-1%). The STHX with Disc-and-Doughnut 10 baffles displays the highest PEC value, establishing it as the most effective STHX in the simulation.

Numerical Heat Transfer Simulation of Oil Shale Large-Size Downhole Heater

Downhole heaters are critical for effectively achieving in situ oil shale cracking. In this study, we simulate the heat transfer performance of a large-scale helical baffle downhole heater under various operational conditions. The findings indicate that at 160 m3/h and 6 kW the outlet temperature can reach 280 °C. Controlling heating power or increasing the injected gas flow effectively mitigates heat accumulation on the heating rod’s surface. The outlet temperature curve exhibits two phases. Simultaneously, a balance in energy exchange between the injected gas and heating power occurs, mitigating high-temperature hotspots. Consequently, the outlet temperature cannot attain the theoretical maximum temperature, referred to as the actual maximum temperature. Employing h/∆p13 as the indicator to evaluate heat transfer performance, optimal performance occurs at 100 m3/h. Heat transfer performance at 200 m3/h is significantly impacted by heating power, with the former being approximately 6% superior to the latter. Additionally, heat transfer performance is most stable below 160 m3/h. The gas heating process is categorized into three stages based on temperature distribution characteristics within the heater: rapid warming, stable warming, and excessive heating. The simulation findings suggest that the large-size heater can inject a higher flow rate of heat-carrying gas into the subsurface, enabling efficient oil shale in situ cracking.

Heat recovery optimization of a shell and tube bundle heat exchanger with continuous helical baffles for air ventilation systems

We report a numerical evaluation of the impact of continuous helical baffle on the heat recovery efficiency of counterflow tube bundle heat exchangers. The baffle inclination angle has been varied from 11∘\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$11^{\\circ }$$\\end{document} to 22∘\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$22^{\\circ }$$\\end{document}. Since the fluid flows over the tube bundle at an angle due to helical flow inside the shell, the heat exchanger operates in cross counter mode. Fluent simulations with the k-ω\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\omega$$\\end{document} transition shear stress transport turbulence model have been performed to investigate the thermal-hydraulic parameters of the system in terms of heat recovery efficiency, pressure loss, and overall heat transfer rate. Outside air temperature has been varied to mimic cold and warm weather. Pressure loss has been constrained to be less than 250 Pa, conforming to EU guidelines for energy labeling of residential ventilation units. At the maximum volume flow rate of 40 m3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^3$$\\end{document}/h, the device performed with over 80%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$80\\%$$\\end{document} heat recovery efficiency for the considered temperature difference. Continuous helical baffles helped to improve convective heat transfer by reducing cross flow area and increasing velocity. Smaller angles result in greater pressure loss while having no discernible effect on heat recovery efficiency for the considered geometry. The analysis demonstrates the potential of a compact counterflowing recuperative heat exchanger with continuous helical baffles for decentralized ventilation systems and serves as a basis for further optimization.

Numerical Comparison of Orifice, Ladder Helical or Segmental Baffle Half-Cylindrical Heat Exchangers

The half-cylindrical heat exchanger is formed by inserting a longitudinal plate in a cylindrical shell space of a U-tube heat exchanger to form dual shell passes for the countercurrent heat transfer purpose. The orifice baffle (OB) in the half-cylindrical shell-side space was proposed to overcome the problems of high-pressure drop in the segmental baffle scheme (SG) and complicated configuration in the unilateral ladder helical baffle scheme (UL). The thermal-hydraulic performances of the bottom part of the half-cylindrical U-tube heat exchanger of four configurations of OBs (fillet triangular, dual-foil square, trefoil, and quatrefoil square), the UL, and the SG were investigated numerically by Fluent in three baffle pitches (50, 40, and 30 mm). The accuracy of the simulated results was validated by experiment with satisfactory agreement. The orifice shape is not sensitive to the performances as long as with a similar flow area. The comprehensive indexes of the schemes OB are very close to that of the UL and much greater than that of the SG, while their overall and shell heat transfer coefficients and pressure drops are lower than those of the schemes UL and SG. Besides, the overall and shell heat transfer coefficients of all schemes increase as the baffle pitch decreases.

The effect of alphabet-shaped twisted tape on thermo-fluidic properties in a shell-tube type heat exchanger: A comparative study utilizing a two-phase mixture model

In the present Computational Fluid Dynamic (CFD) simulation, the impact of various shapes of alphabet twisted tape in a shell –tube type of heat exchanger on the pressure drop, temperature, velocity distribution, and heat transfer coefficient was studied numerically. The best shape of the twisted tape was selected by thermo-hydraulic analysis. SIMPLE algorithm and Finite Volume Method (FVM) were then implemented to solve the conversion formulas. Conversion equations were discretized using second-order upwind discretization. Comparing the results of different types of twisted tape, Case I (W-shaped tape) exhibited the best performance and the utmost pressure differences. Furthermore, the utmost heat transfer factor was obtained by W shape twisted tape. Also, the helical baffles illustrated the best performance of the shell-part baffles in the shell-tube type of heat exchanger. Comparison between single and two-phase flow by utilizing mixture model for heat transfer factor and pressure difference reveal the negligible changes. On the quant part, FOM amount have been shown a great significance (1.3439) in the shell part for helical baffle type.

Numerical Simulation of Thermo-hydraulic Behaviour of Shell and Tube Heat Exchanger Equipped with Segmental Baffle and Helical Baffle

The baffle type and structure are critical to enhancing the comprehensive thermo-hydraulic behavior of shell-and-tube heat exchangers (STHX). In the study, Solidworks software was used to establish three-dimensional mesh models of STHX equipped with the segmental baffle and the continuous helical baffle, respectively. ANSYS software was adopted to study the effects of the baffle type and the baffle geometric parameters on the thermo-hydraulic characteristic of STHXs using the pressure drop of the shell side, the coefficient of heat transfer and isobaric JFP factor as the evaluation characteristics. For segmental baffles, better thermo-hydraulic performance could be obtained with a baffle spacing of 200 mm and a gap height of 0.4 D. For helical baffles, an optimized thermo-hydraulic performance could be obtained with a baffle pitch of 150 mm. By comparing the comprehensive thermo-hydraulic performances of STHXs equipped with two different baffles, it could be concluded that the isobaric JFP factor of STHX equipped with the helical baffle was 1.18 times that of STHX equipped with the segmental baffle under the different suitable flow rate.

Enhancement of Heat Transfer Rate with a Low-Pressure Drop in Shell and Tube Heat Exchanger through Optimal Spacing of Helical Baffle

Enhancement of Heat Transfer Rate with a Low-Pressure Drop in Shell and Tube Heat Exchanger through Optimal Spacing of Helical Baffle

Flow Characteristics and Heat Transfer Performances of Quadrant Helical Baffle Heat Exchanger with Grooved Joint

Helical baffle heat exchanger has a wide application in many industrial fields because of its high efficiency and low resistance. A new structure of the grooved helical baffle is proposed to strengthen the stability between the overlapped baffles during the spiral flow of fluid. Based on this structure, the liquid water was selected as the working medium in the tube side and shell side, the flow field characteristics and heat transfer performances of the quadrant helical baffle heat exchanger are numerically analyzed using software FLUENT 2017. The results show that when the helical angle is large (50°) and the overlapped amount is small (0.5), the comprehensive performance of the heat exchanger is the best. Therefore, the heat exchanger performance can be improved by choosing the appropriate combination of helical angle and overlapped amount. The correlation formula of the shell side heat transfer coefficient with helical angle, overlapped amount and mass flow rate is obtained by means of regression analysis, which can provide a reference for engineering application and optimal design of grooved helical baffle heat exchanger.

Computational fluid dynamics study of gas-liquid mass transfer in concentric tube airlift reactor with helical baffle

This work aims to understand the effect of stationary and rotational helical baffle on gas-liquid mass transfer in concentric tube airlift reactor. A computational fluid dynamics (CFD) method is conducted, and the predicted of overall volumetric mass transfer coefficient (KLa) in concentric tube airlift reactor (0.29 m diameter and 1.5 m initial liquid height) without baffle is validated reasonable agreement with the empirical equations reported in the literatures. The results were simulated basing on this validated model. It indicated that the helical baffle with the same width of riser (40 mm) could increase the KLa by 132∼202% at the superficial gas velocity of 0.00212 m·s−1 when compared with that the airlift reactor without baffle. At the width of helical baffle less than width of riser, the KLa decreased with the decreasing of the width (W) and the rotational speed (n) of helical baffle. When the width of stationary helical baffle is 30 mm, the effect of helical baffle on enhancing mass transfer is negligible. In addition, the KLa decreased with the increasing of the helix pitch (H) of helical baffle and the distance of the lower edge of helical baffle from the bottom of reactor (L).

Experimental investigation of heat transfer characteristics for a shell and tube heat exchanger

Abstract In the present work, numerical investigations are conducted with 22 % cut segmental baffle heat exchanger (SB), 20°, 30°, and 40° helical baffles shell and tube heat exchangers (STHX) to estimate the overall heat transfer coefficient (OHTC), pressure drop (PD) and friction factor. Among the studied heat exchangers (HE), 40° helical baffles STHX provided the highest OHTC with minimum pressure drop. Hence, further investigations are conducted experimentally with 40° helical baffles STHX. OHTC increased by 2.65 % for 20° helical baffles, 5.37 % for 30° helical baffles, 9.78 % for 40° helical baffles when compared with 22 % cut segmental baffle heat exchanger. The deviation between experimental and numerical OHTC is 2.64 % 40° helical baffles.

Computation of thermal properties of CMSP shell and tube heat exchanger using different types of helical baffles

AbstractThis paper investigates the flow and thermal properties of a combined multiple shell pass (CMSP)‐shell and tube heat exchanger (STHE) with the provision of unilateral ladder‐type helical baffle (ULHB) and continuous helical baffle (HB) in the outer shell pass of the heat exchanger. Two CMSP‐STHEs with ULHB and HB, respectively, are compared with the traditional STHE having segmental baffles (SG‐STHE) using the computational fluid dynamics method. The computational outcomes are validated with the empirical correlations of the Kern and Esso method. The Reynolds‐averaged Navier–Stokes‐based standard k–ω turbulence model accurately predicts the heat transfer (HT) rate and pressure drop. The computed results of HT rate, pressure drop, and logarithmic mean temperature difference corresponding to various mass flow rates (m) for three STHEs are presented. The results show that the overall HT rate of CMSP (ULHB)‐STHE and the CMSP (HB)‐STHE at the same mass flow rate are nearly 28.3% and 14.8% larger than that of traditional SG‐STHE, respectively. Furthermore, the overall area‐weighted average pressure drop (ΔP) of CMSP (HB)‐STHE is smaller than that of SG‐STHE by 26.5% at the same mass flow rate (m) and for CMSP (ULHB)‐STHE it is larger by 2% than that of traditional STHE. Based on the above results, it is concluded that the CMSP (ULHB)‐STHE is a suitable replacement for the conventional SG‐STHEs.

Numerical investigation of thermo-hydraulic ability of STHX with continuous helical baffles on the shell side

The larger quantities of heat transfer rates are possible with the modification of few parameters like baffle cut and shape. Which significantly improves the performance of shell and tube heat exchanger while reducing the pressure drop. From the reported literature review it was proposed to carry the numerical analysis for various helix angles. The present study is to simulate heat transfer rate and liquid movement in a shell-and-tube heat exchanger along with continuous helical-baffles on the shell side. The numerical investigation of seven helix angles, namely 10°, 19°, 21°, 25°, 30°, 38°, and 50°, is done for varying mass flow rates and the inlet temperature of shell side and tube side are 25 °C and 55 °C respectively, modelled a whole length unceasing helical-baffled shell-and-tube heat exchanger. Larger helix angles (30°, 38°, and 50°) result in reduced heat transfer rate and pressure drop too low, while minor helix angles (10°, 19°, 21°, and 25°) result in increased heat transfer rate and pressure drop too high.

Thermal Performance and Turbulence Modeling of Combined Multiple Shell-Pass Shell and Tube Heat Exchanger

Abstract This paper investigates the adaptability of different Reynolds-averaged Navier-Stokes (RANS)-based turbulence models for flow behavior and thermal performance of combined multiple shell-pass shell and tube heat exchanger (CMSP-STHE) with unilateral ladder-type helical baffle (ULHB). The presence of ULHB in the outer shell pass of the heat exchanger leads to a complex flow configuration and makes it quite challenging to deal with its computational analysis. The computational fluid dynamic method compares the CMSP-STHE with ULHB with the traditional shell and tube heat exchanger with segmental baffles (SG-STHE). The performance of four turbulence models, namely, realizable k–ɛ, standard k–ɛ, standard k–ω and RNG k–ɛ models are compared with the correlation data. It is observed that the standard k–ω turbulence model more accurately predicts the heat transfer and pressure drop compared to other models. The logarithmic mean temperature difference (LMTD) results for various mass flowrates and thermal performance enhancement factor (TPEF) corresponding to various values of Re are also presented. It is concluded that the TPEF of CMSP (ULHB)-STHE is higher than that of the conventional STHE. The average enhancement is approximately 28% for ULHB STHE than the conventional one. Further, variations in velocity, turbulence kinetic energy, and local Nusselt number along the tube length are examined to understand the thermal performance behavior with CMSP (ULHB)-STHE. It is clear from the results that the CMSP (ULHB)-STHE is a better alternative to the traditional SG-STHEs.

Retraction Note: Numerical assessment of the influence of helical baffle on the hydrothermal aspects of nanofluid turbulent forced convection inside a heat exchanger

Retraction Note: Numerical assessment of the influence of helical baffle on the hydrothermal aspects of nanofluid turbulent forced convection inside a heat exchanger

Enhancing the efficiency and speed of heat transfer using shell and tube heat exchanger design

The Heat Exchanger requires the least amount of initial investment and continuing maintenance while transferring energy at a maximum or minimum rate from a hot fluid to a cold fluid. With this technique, fluids are never mixed. Because they are used at high pressures and temperatures, Shell and Tube Heat Exchangers are always being improved in terms of efficiency and heat transfer rate. In this study, we suggest a design technique for a shell and tube heat exchanger that can increase the efficiency and rate of heat transfer. It consists of a tube, a tube inlet, a tube outlet, a shell, a shell inlet, a shell outlet, baffle plates, a circular tube bundle, and a baffle pitch. Three alternative pitches-Pitch-80, Pitch-60, and Pitch-40 with similar hot and cold water temperatures were taken into consideration when designing the heat exchanger described here. The helical baffle construction with Pitch Layouts is modified with varied specifications using Pitch-80, Pitch-60, and Pitch-40 and simulated with ANSYS R19.2 in the current invention (Fluent). When compared to the