Computational analysis for the effect of the taper angle and helical pitch on the heat transfer characteristics of the helical cone coils (original) (raw)
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This numerical research is introducing the concept of helical cone coils and their enhanced heat transfer characteristics compared to the ordinary helical coils. Helical and spiral coils are known to have better heat and mass transfer than straight tubes, which is attributed to the generation of a vortex at the helical coil known as Dean Vortex. The Dean number which is a dimensionless number used to describe the Dean vortex is a function of Reynolds number and the square root of the curvature ratio, so varying the curvature ratio for the same coil would vary the Dean number. Two scenarios were adopted to study the effect of changing the taper angle (curvature ratio) on the heat transfer characteristics of the coil; the commercial software FLUENT was used in the investigation. It was found that Nusselt number increased with increasing the taper angle. A MATLAB code was built based on empirical correlation of Manlapaz and Churchill for ordinary helical coils to calculate the Nusselt number at each coil turn, and then calculate the average Nusselt number for the entire coil turns, the CFD simulation results were found acceptable when compared with the MATLAB results.
An Experimental and CFD Analysis on Helical Coil Heat Exchanger with Different Geometry
International Journal of Analytical, Experimental and Finite Element Analysis (IJAEFEA)
An attempt is made here to investigate the effect of geometric features especially different geometric shape of coil on single phase flow and convective heat transfer characteristics by experimentally and using CFD technique. An experimentation done on helical, conical and spiral coil. Copper tube of internal diameter 9.5 mm , 1.5 mm thickness and 3000 mm long is used for experimentation. Readings recorded for different mass flow rate(15 LPH,20LPH, 25LPH). Comparative analysis shows that convective heat transfer rate of helical coil tube heat exchanger is 9.54% more than conical and spiral coil heat exchanger. Nusselt number increase as the mass flow rate increase. Helical coil heat exchanger is more efficient than conical and spiral coil heat exchanger. The Computational Fluid Dynamics (CFD) software has been used for simulation of heat exchanger. Experimentation conducted on new heat exchanger for particular mass flow rate and data is maintained as per various flow rate. The experimental results of water outlet temperature are validated with the results obtained by using computational fluid dynamics (CFD) tool and there is a good agreement in between them.
A Review on Study of Heat Transfer Analysis of Helical Coil Heat Exchangers
International Journal of Trend in Scientific Research and Development, 2021
Now a day's a geometrically modified Helical coil heat exchangers are widely using in industrial applications like cryogenic state processes, airconditioning, thermal nuclear reactors and waste heat recovery due to their compact size and high heat transfer coefficient. Advantage of using helical coils over straight tubes is that the residence time spread is reduced, allowing helical coils to be used to reduce axial dispersion in tubular reactors. In this study, numerical investigation of the influence of geometrical parameters such as tube diameter (d), coil radius(R), and coil pitch(p) on overall heat transfer coefficient in helical double tube heat exchangers are performed using a professional CFD software-FLUENT. In recent years, numerous styles were introduced for heat exchangers that apply to completely different applications; sadly, their heat transfer coefficient wasn't reliable at different operational conditions. the standard of the heat changed rate wasn't optimized and there have been many deficiencies and errors in styles. The heat transfer of the copper material is enhanced in comparison with other material unfortunately thermal resistance is reduced with an increase in pressure drop thus enhancing the heat transfer on the heat exchanger. Helical architecture is often designed with a clear motive of compact size and also address heat transfer coefficient and other ancillary attributes efficiently and effectively. So the better material is suggested for an industrial heat exchanger according to the applications is Copper with the basis of simulation results. The geometry and different dimension parameter of the helical coil show that the proposed study in different material properties and different mass flow rates to heat transfer are maximum in different parameter helical coil heat exchangers. Finally, the heat transfer increase for the copper material compared to another material but with the increase in pressure drop the corresponding thermal resistance decreases which allow the improved heat transfer rate and the rate increases from Aluminum to Bronze to Copper. With the drop in temperature, the thermal resistance is reduced which enhances the heat transfer rate. The simulation results show that the copper has a high heat transfer coefficient than Aluminum and Bronze while operating in identical conditions. Due to the extensive use of helical coils in various applications, knowledge about the flow patterns and heat transfer characteristics are important.
IJERT-Parametric Analysis of Helical Coil Heat Exchanger
International Journal of Engineering Research and Technology (IJERT), 2012
https://www.ijert.org/parametric-analysis-of-helical-coil-heat-exchanger https://www.ijert.org/research/parametric-analysis-of-helical-coil-heat-exchanger-IJERTV1IS8376.pdf Heat exchangers are the important engineering systems with wide variety of applications including power plants, nuclear reactors, refrigeration and airconditioning systems, heat recovery systems, chemical processing and food industries. Helical coil configuration is very effective for heat exchangers and chemical reactors because they can accommodate a large heat transfer area in a small space, with high heat transfer coefficients. This paper deals with the parametric analysis of the helical coiled heat exchanger with various correlations given by different researchers for specific conditions. The parametric analysis of these various correlations with specific data is presented in this paper.
CFD analysis of heat transfer in a helical coil heat exchanger using fluent
2013
Heat exchangers are the important engineering systems with wide variety of applications including powerplants, nuclear reactors, refrigeration and air-conditioning systems, heat recovery systems, chemical processing and food industries. Helical coil configuration is very effective for heat exchangers and chemical reactors as they can accommodate a large heat transfer area in a small space, with high heat transfer coefficients. This project deals with the analysis of the helical coiled heat exchanger with various correlations given by different papers for specific conditions. Although various configurations are available, the basic and most common design consists of a series of stacked helically coiled tubes placed in a helical outer cover. The inner tube ends are connected to manifolds, which act as fluid entry and exit locations. And the outer tube is provided with inlet and outlet manifolds so that cooling fluid can be passed through it. The tube bundle is constructed of a number ...
Performance Analysis of Helical Coil Heat Exchanger Using Numerical Technique
Helical coil heat exchangers are widely used in applications requiring large heat transfer area per unit volume. In present work, CFD simulation of helical coiled heat exchanger has been done. The diameter coil of heat exchanger has been varied along with mass flow rate. Water at 332 K has been considered at inlet. Parameters such as temperature drop, heat transfer rate, heat transfer coefficient and Nusselt number have been found out and compared for the geometric variations and variation in mass flow rate. It has been found out that temperature drop decreases for decrease in diameter of coil and also for increase in mass flow rate whereas heat transfer rate increases with increase in coil diameter and mass flow rate.
Parametric Analysis of Helical Coil Heat Exchanger
Heat exchangers are the important engineering systems with wide variety of applications including power plants, nuclear reactors, refrigeration and airconditioning systems, heat recovery systems, chemical processing and food industries. Helical coil configuration is very effective for heat exchangers and chemical reactors because they can accommodate a large heat transfer area in a small space, with high heat transfer coefficients. This paper deals with the parametric analysis of the helical coiled heat exchanger with various correlations given by different researchers for specific conditions. The parametric analysis of these various correlations with specific data is presented in this paper.
Gourav Vivek Kulkarni, 2017
Heat Exchangers are of utmost industrial importance in the field of Power generation, Refrigeration, Air Conditioning, Nuclear energy and numerous other applications. However it is required to utilize the heat energy of the hot fluid to the optimum extent in order to come up with much more efficient energy systems. The classic design of a heat exchangers mainly consists of a shell and tube. The tube is enclosed within the shell and generally caries the hot fluid. The shell carries the cold fluid. There are various flow arrangements that can facilitate enhanced heat transfer. However by continuous research, it was found that straight tube heat exchangers were not providing the required cooling effect to the desired extent. This has led to the development of Helical coil Heat exchangers in which, instead of a straight tube, a helical tube is used. The heat transfer analysis in helical coil heat exchangers is the next step towards performance evaluation and optimization of the system. This can be accomplished in two ways. One being experimentation and the other being numerical estimation by means of Computational Fluid Dynamics (CFD). This work elaborates the methodology undertaken in experimentation as well as the analysis done by means of CFD considering three cases. The experimental procedure comprises of making the fluid to flow at various mass flow rates and obtaining the heat transfer characteristics. However the experimental results are prone to a certain external factors that can affect the results. This limitation can be overcome by using CFD where everything is pre-programmed and solutions totally depend on the mathematical models and equations. Further the same model is developed using suitable software and the fluid flow simulation is carried out. Various boundary conditions like temperature, heat flux and other temperature dependent thermal and transport properties are well defined during the pre processing stage. Solutions are carried out to obtain the results of simulation. The chief objective is to establish a correlation between the experimental results and the CFD results. On obtaining the results, critical comparison is done with regards to the corresponding results obtained from experimentation and CFD. Thus we can look at CFD as an excellent tool to analyze fluid flow systems with lesser investment as compared to experimentation. Since the fluid flow through the Helical coil Heat exchangers has got complex flow characteristics, there may be certain areas where CFD can provide results that have got much more realistic values. At the end a conclusion is drawn as to which method of analysis can prove to be handy as well as reliable since the areas in which Helical Coil heat exchangers are used now a days are of extreme technical importance.
Heat transfer in helical coil heat exchanger: An experimental parametric study
2019
Helical coil heat exchangers are widely used in a variety of industry applications such as refrigeration systems, process plants and heat recovery. In this study, the effect of Reynolds number and the operating temperature on heat transfer coefficients and pressure drop for laminar flow conditions was investigated. Experiments were carried out in a shell and tube heat exchanger with a copper coiled pipe (4 mm ID, length of 1.7 m and coil pitch of 7.5 mm) in the temperature range from 243 to 273 K. Air – propan-2-ol vapor mixture and coolant (methylsilicone oil) flowed inside and around the coil, respectively. The fluid flow in the shell-side was kept constant, while in the coil it was varied from 6.6 to 26.6 m/s (the Reynolds number below the critical value of 7600). Results showed that the helical pipe provided higher heat transfer performance than a straight pipe with the same dimensions. The convective coefficients were determined using the Wilson method. The values for the coile...
IJERT-Computational Fluid Dynamic Analysis for Optimization of Helical Coil Heat Exchanger
International Journal of Engineering Research and Technology (IJERT), 2016
https://www.ijert.org/computational-fluid-dynamic-analysis-for-optimization-of-helical-coil-heat-exchanger https://www.ijert.org/research/computational-fluid-dynamic-analysis-for-optimization-of-helical-coil-heat-exchanger-IJERTV5IS040879.pdf Helically coiled heat exchangers are used in order to obtain a large heat transfer area per unit volume and to enhance the heat transfer coefficient on the inside surface. The enhancement in heat transfer due to helical coils has been reported by many researchers by experimental setups for the estimation of the heat transfer characteristics. In this thesis the experimental results are compared with the CFD calculation results using the CFD software package ANSYS CFX used by the many researchers. Further a computational study has been accomplished to determine the effects of heat transfer in the helical coiled heat exchanger by considering the parameters like pitch length of helical coil and mass flow rate of fluids in helical coil heat exchanger. It is concluded that the CFD analysis results fairly matches with the Experimental Results. A comparison with experimental results and CFD simulations has proved that by decreasing the pitch length of helical coil and relative velocity of fluids in helical coil heat exchanger, increases heat transfer rate.