The Experts below are selected from a list of 7599 Experts worldwide ranked by ideXlab platform
Bengt Sunden - One of the best experts on this subject based on the ideXlab platform.
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cfd analysis of two types of welded Plate Heat Exchangers
Numerical Heat Transfer Part A-applications, 2017Co-Authors: Huibao Luan, J P Kuang, Zan Wu, Bengt SundenAbstract:A numerical and experimental study has been carried out on the Heat transfer and fluid flow in two types of welded Plate Heat Exchangers (PHEs). A new approach providing a proper clearance between two adjacent corrugated Plates is proposed to improve the mesh quality around the contact points. The clearance value and the influence on the mesh quality and computational results are carefully studied. The results show that a relative clearance of 0.02 is proper. The computational fluid dynamics (CFD) results agree with the experimental results with a deviation of 15%. The proposed approach is proved effective and practical because it can increase the grid quality without losing the accuracy of the results. This paper shows that CFD is a reliable tool for studying the effects of various geometrical configurations on the optimum design of a PHE.
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cfd simulation of Heat transfer and pressure drop in compact brazed Plate Heat Exchangers
Heat Transfer Engineering, 2014Co-Authors: Vijaya Sekhar Gullapalli, Bengt SundenAbstract:In this paper, the thermal and hydraulic characteristics of corrugated fluid channels of compact brazed Plate Heat Exchangers (BPHE) are investigated by computational fluid dynamics (CFD) simulations using the commercial CFD software ANSYS CFX 14.0. The influence of geometry parameters of the corrugated pattern such as chevron angle and corrugation pitch on the BPHE performance is investigated on small fluid section geometries. The influence of various types of wall Heat transfer boundary conditions on the simulation results is also studied. An entire fluid channel is simulated using various turbulence models in the Reynolds number range of 300 to 3000. The CFD predictions are also validated using data obtained from laboratory experiments. The simulations of the entire fluid channel underpredict Heat transfer and pressure drop by 20–30% and 10–35%, respectively. The results from the small fluid sections suggest that the CFD simulations can be used as a reasonably effective tool in determining the relative...
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Plate Heat Exchangers design applications and performance
2007Co-Authors: Lieke Wang, Raj M Manglik, Bengt SundenAbstract:Heat Exchangers are important, and used frequently in the processing, Heat and power, air-conditioning and refrigeration, Heat recovery, transportation and manufacturing industries. Such equipment is also important in electronics cooling and for environmental issues like thermal pollution, waste disposal and sustainable development. The present book concerns Plate Heat Exchangers (PHEs), which are one of the most common types in practice. The overall objectives are to present comprehensive descriptions of such Heat Exchangers and their advantages and limitations, to provide in-depth thermal and hydraulic design theory for PHEs, and to present state-of-the-art knowledge. The book starts with a general introduction and historical background to PHEs, then discusses construction and operation (PHE types, Plate pattern, etc.) and gives examples of PHEs in different application areas. Material issues (Plates, gaskets, brazing materials) and manufacturing methods are also treated. The major part of the book concerns the basic design methods for both single-phase and two-phase flow cases, various flow arrangements, thermal-hydraulic performance in single-phase flow and for PHEs operating as condensers and evaporators. Fouling problems are also discussed and in a section on extended design and operation issues, modern Research and Development (R & D) tools like computational fluid dynamics (CFD) methods are discussed. Unique features for PHEs are discussed throughout (Less)
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transient response of Plate Heat Exchangers considering effect of flow maldistribution
International Journal of Heat and Mass Transfer, 2005Co-Authors: N Srihari, Bengt SundenAbstract:Plate Heat Exchangers have been playing important role in the power and process industries in the recent past. Hence, it is important to develop simulation strategies for Plate Heat Exchangers accurately. This analysis represents the dynamic behaviour of the single pass Plate Heat Exchangers, considering flow maldistribution from port to channel. In addition to maldistribution the fluid axial dispersion is used to characterise the back mixing and other deviations from plug flow. Due to unequal distribution of the fluid, the velocity of the fluid varies from channel to channel and hence the Heat transfer coefficient variation is also taken into consideration. Solutions to the governing equations have been obtained using the method of Laplace transform followed by numerical inversion from frequency domain. The results are presented on the effects of flow maldistribution and conventional Heat exchanger parameters on the temperature transients of both U-type and Z-type configurations. It is found that the effect of flow maldistribution is significant and it deteriorates the thermal performance as well as the characteristic features of the dynamic response of the Heat exchanger. In contrast to the previous studies, here the axial dispersion describes the inchannel back mixing alone, not maldistribution, which is physically more appropriate. Present method is an efficient and consistent way of describing maldistribution and back mixing effects on the transient response of Plate Heat Exchangers using an analytical method without performing intensive computation by complete numerical simulation.
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an experimental and theoretical investigation of the effect of flow maldistribution on the thermal performance of Plate Heat Exchangers
Journal of Heat Transfer-transactions of The Asme, 2005Co-Authors: Bengt SundenAbstract:An experimental and theoretical study of the effect of flow maldistribution from port to channel on the thermal performance of single and multipass Plate Heat Exchangers is presented. In general, flow maldistribution brings about an increase in pressure drop and decrease of the thermal performance in Heat Exchangers. This deterioration is found to depend on flow rate, number of channels, and port size. Experiments show that analytical predictions of pressure drop and thermal performance in presence of flow maldistribution are quite accurate for practical purposes. The results indicate that under identical conditions, maldistribution is more severe in Z-type Plate Heat exchanger compared to U type. Multipassing is found to reduce the maldistribution effect significantly. An insight to the physical aspects of maldistribution and its possible reduction through proper design strategy are also presented. (Less)
Eugeny Y Kenig - One of the best experts on this subject based on the ideXlab platform.
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determination of the geometric design parameters of pillow Plate Heat Exchangers
Applied Thermal Engineering, 2015Co-Authors: Mark Piper, Alexander Olenberg, J M Tran, Eugeny Y KenigAbstract:Abstract Pillow-Plate Heat Exchangers (PPHE) are characterized by their wavy “pillow-like” surface and fully welded construction. They represent a promising alternative to conventional Heat Exchangers and are commonly encountered as condensers in the process industry. However, in contrast to conventional devices, there are no reliable design methods available for PPHE in the literature, which hinders expansion of PPHE application. In this study, a determination method for the hydraulic diameter, cross-sectional area and Heat transfer area is proposed for pillow-Plate geometries. The method is based on forming simulations, which accurately reproduce the inherently three-dimensional wavy pillow-Plate channels by imitating the real manufacturing process of pillow Plates. The simulation results are then used to develop simple expressions for the geometric design parameters.
Jie Yang - One of the best experts on this subject based on the ideXlab platform.
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Heat transfer correlations for single phase flow in Plate Heat Exchangers based on experimental data
Applied Thermal Engineering, 2017Co-Authors: Jie Yang, Anthony M JacobiAbstract:Abstract In the present paper, the single-phase Heat transfer for nine brazed-Plate Heat Exchangers with different geometric parameters is experimentally investigated. An ethylene glycol and water mixture is used as working fluid. First, the results show that the herringbone angle is the most dominant factor influencing Heat transfer. Then, the results also show that geometric dimensions affect Heat transfer jointly with herringbone angle. Individual correlations and a general correlation based on experimental data are presented. Then the empirical equations are compared to existing correlations from the open literature. Based on archival data and the experimental data presented in this work, a generalization of single-phase Heat transfer performance of Plate Heat Exchangers is given, relating the Nusselt number to Heat exchanger geometry, Reynolds number, and fluid properties. The proposed correlation is based on experiments of 22 Heat Exchangers and 25 empirical correlations, and the percent root-mean-square deviation is 20.77%. This novel correlation has the accuracy of 50% and it is applicable for a very large range of Plate Heat Exchangers.
Reinhard Radermacher - One of the best experts on this subject based on the ideXlab platform.
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a survey of correlations for Heat transfer and pressure drop for evaporation and condensation in Plate Heat Exchangers
International Journal of Refrigeration-revue Internationale Du Froid, 2016Co-Authors: Radia Eldeeb, Vikrant Aute, Reinhard RadermacherAbstract:Abstract Plate Heat Exchangers (PHEs) are used in a wide variety of applications including Heating, ventilation, air-conditioning, and refrigeration. PHEs are characterized by compactness, flexible thermal sizing, close approach temperature, and enhanced Heat transfer performance. Due to their desirable characteristics, they are increasingly utilized in two-phase flow applications. Detailed research on Heat transfer and fluid flow characteristics in these types of Exchangers is required to design and use Plate Heat Exchangers in an optimal manner. This paper reviews the available literature on the correlations for Heat transfer and pressure drop calculations for two-phase flow in PHEs as an initial process step in order to understand the current research status. Comparative evaluations for some of the existing correlations are presented in the light of their applicability to different refrigerants. Overall, there is a significant gap in the literature regarding two-phase Heat transfer and fluid flow characteristics of these types of Exchangers.
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a new model for Plate Heat Exchangers with generalized flow configurations and phase change
International Journal of Refrigeration-revue Internationale Du Froid, 2013Co-Authors: Hongtao Qiao, Vikrant Aute, Khaled Saleh, Reinhard RadermacherAbstract:A new model has been developed for the analysis of Plate Heat Exchangers with multi-fluid, multi-stream and multi-pass configurations. The model divides the entire Heat exchanger into multiple slices in the direction of fluid flow. For the channels in each slice, the wall temperatures are assumed to be constant such that each channel can be solved without the need of knowing the fluid condition in the adjacent channels. In the top level, all the slices are iterated using a successive substitution approach. The model is capable of handling both single-phase and two-phase flow. In general, Plate Heat Exchangers are used with two to three fluids, but the model is capable of handling more than three fluids wherein each fluid can undergo phase change. The model was verified against the P-NTU closed form expressions for single-phase flow in Plate Heat Exchangers with various flow configurations. The model was validated against in-house experimental data for single-phase water, two-phase ammonia and R22 boiling. The effect of discretization and the speed up on multiple cores was investigated.
Yong Tae Kang - One of the best experts on this subject based on the ideXlab platform.
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review condensation and evaporation characteristics of low gwp refrigerants in Plate Heat Exchangers
International Journal of Air-conditioning and Refrigeration, 2016Co-Authors: Byung Hoon Shon, Seung Won Jeon, Yong Tae KangAbstract:In this paper, condensation and evaporation characteristics of low global warming potential (GWP) refrigerants such as R-1234yf and R-1234ze series are reviewed. This review focuses on Heat transfer and pressure drop in Plate Heat Exchangers. Mass flux is considered as an important factor while saturation temperature is not for condensation and evaporation process in Plate Heat Exchangers. The dryout phenomenon occurs occasionally and gives greatly harmful impact on evaporation Heat transfer. It is found that R-1234yf and R-1234ze(E) give slightly lower Heat transfer performance than R-134a for both condensation and evaporation processes. Generally, low GWP refrigerants presented in this review give lower Heat transfer coefficient and higher frictional pressure drop than the conventional refrigerants. Nevertheless, R-1234ze(Z) gives superior Heat transfer performance than other refrigerants in condensation. R-32 gives remarkable performance in evaporation, but it gives relatively high GWP compared to other low GWP refrigerants.
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EXPERIMENTAL STUDY ON Heat TRANSFER AND PRESSURE DROP CHARACTERISTICS FOR WELDED EMBOSSING TYPE Plate Heat Exchangers
International Journal of Air-Conditioning and Refrigeration, 2011Co-Authors: Jong Yun Jeong, Chung Woo Jung, Yong Tae KangAbstract:Heat transfer and pressure drop characteristics of the welded Plate Heat Exchangers are experimented to apply the high- and low-temperature solution Heat exchanger (SHX) of absorption systems. Two different SHXs were made using the seam and tig welding method. In this paper, the welded embossing type Plate Heat Exchangers were tested by controlling mass flow rate and inlet/outlet temperatures. It was found that Heat transfer and pressure drop performance increased with increasing Reynolds number. It was also found that the pressure drop from the present W-embossing type Plate Heat exchanger was much lower than that from the brazed type, as low as 1/7 times. The experimental correlations for Nusselt number and Fanning friction factor were developed with the error bands of ± 20% and ± 25%, respectively. These results provide a guideline to apply the welded Plate Heat exchanger for the solution Heat exchanger of absorption systems.
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A Numerical Analysis on the Heat Transfer and Pressure Drop Characteristics of Welding Type Plate Heat Exchangers
Transactions of The Korean Society of Mechanical Engineers B, 2008Co-Authors: Jong Yun Jeong, Yong Tae KangAbstract:Abstract Numerical analysis was carried out to examine the Heat transfer and pressure drop characteristics of Plate Heat Exchangers for absorption application using Computational Fluid Dynamics(CFD) technique. A commercial CFD software package, FLUENT was used to predict the characteristics of Heat transfer, pressure drop and flow distribution within Plate Heat Exchangers. In this paper, a welded Plate Heat exchanger with the Plate of chevron embossing type was numerically analyzed by controlling mass flow rate, solution concentration, and inlet temperatures. The working fluid is H 2 O/LiBr solution with the LiBr concentration of 50-60% in mass. The numerical simulation shows reasonably good agreement with the experimental results. Also, the numerical results show that Plate of the chevron shape gives better results than Plate of the elliptical shape from the view points of Heat transfer and pressure drop. These results provide a guideline to apply the welded PHE for the solution Heat exchanger of absorption systems.기호설명 : 수력직경(m) : 패닝 마찰 계수 : 난류 강도 : 열전도율(W/m․K) : 질량유량(kg/s)