Pub Date : 2019-01-09DOI: 10.5772/INTECHOPEN.83376
Laura Gómez
tech-nics cannot match the requirements of a flexible and adaptive form finding. Instead, we exploit biomimetic and mathematical approaches with parametric modeling. This results in unseen configurations and pushes the limits of how we should think about heat exchangers today. The section of working fluids, “Heat flow inside heat exchanger using Al 2 O 3 nanofluid with different concentrations” by Jaafar Albadr, shows an experimental investigation on a forced convection heat flow and characteristics of a nanofluid containing water with different vol ume concentrations of Al 2 O 3 nanofluid (0.3–2%) flowing inside a horizontal shell and tube heat exchanger in a counterflow under turbulent conditions. The Al 2 O 3 nanoparticles of about 30 nm diameter are utilized. The results indicate that the convective heat transfer coefficient of nanofluid is higher than that of the base liquid at same inlet temperature and mass flow rate. The heat transfer coefficient of the nanofluid increases with the increase in mass flow rate. Furthermore, the heat transfer coefficient increases with the increase in the Al 2 O 3 nanofluid volume concentration. Results illustrate that the increase in volume concentration of the nanoparticles leads to an increase in the viscosity of the nanofluid which causes an increase in friction factor. The effects of Peclet number, Reynolds number, and Nusselt number have been investigated. Those dimensionless number values change with the change in the work ing fluid viscosity, Prandtl number, and volume concentration of suspended nanoparticles.
{"title":"Introductory Chapter: Heat Exchangers","authors":"Laura Gómez","doi":"10.5772/INTECHOPEN.83376","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.83376","url":null,"abstract":"tech-nics cannot match the requirements of a flexible and adaptive form finding. Instead, we exploit biomimetic and mathematical approaches with parametric modeling. This results in unseen configurations and pushes the limits of how we should think about heat exchangers today. The section of working fluids, “Heat flow inside heat exchanger using Al 2 O 3 nanofluid with different concentrations” by Jaafar Albadr, shows an experimental investigation on a forced convection heat flow and characteristics of a nanofluid containing water with different vol ume concentrations of Al 2 O 3 nanofluid (0.3–2%) flowing inside a horizontal shell and tube heat exchanger in a counterflow under turbulent conditions. The Al 2 O 3 nanoparticles of about 30 nm diameter are utilized. The results indicate that the convective heat transfer coefficient of nanofluid is higher than that of the base liquid at same inlet temperature and mass flow rate. The heat transfer coefficient of the nanofluid increases with the increase in mass flow rate. Furthermore, the heat transfer coefficient increases with the increase in the Al 2 O 3 nanofluid volume concentration. Results illustrate that the increase in volume concentration of the nanoparticles leads to an increase in the viscosity of the nanofluid which causes an increase in friction factor. The effects of Peclet number, Reynolds number, and Nusselt number have been investigated. Those dimensionless number values change with the change in the work ing fluid viscosity, Prandtl number, and volume concentration of suspended nanoparticles.","PeriodicalId":348821,"journal":{"name":"Advances in Heat Exchangers","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115190839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-11-05DOI: 10.5772/INTECHOPEN.80010
U. Scheithauer, R. Kordass, K. Noack, M. Eichenauer, Mathias Hartmann, Johannes Abel, G. Ganzer, Daniel Lordick
Additional information available at the end of the chapter Abstract The rapid development of additive manufacturing (AM) technologies enables a radical paradigm shift in the construction of heat exchangers. In place of a layout limited to the use of planar or tubular starting materials, heat exchangers can now be optimized, reflecting their function and application in a particular environment. The complexity of form is no longer a restriction but a quality. Instead of brazing elements, resulting in rather inflexible standard components prone to leakages, with AM, we finally can create seam-less integrated and custom solutions from monolithic material. To address AM for heat exchangers we both focus on the processes, materials, and connections as well as on the construction abilities within certain modeling and simulation tools. AM is not the total loss of restrictions. Depending on the processes used, delicate constraints have to be considered. But on the other hand, we can access materials, which can operate in a much wider heat range. It is evident that conventional modeling techniques cannot match the requirements of a flexible and adaptive form finding. Instead, we exploit biomimetic and mathematical approaches with parametric modeling. This results in unseen configura-tions and pushes the limits of how we should think about heat exchangers today.
{"title":"Potentials and Challenges of Additive Manufacturing Technologies for Heat Exchanger","authors":"U. Scheithauer, R. Kordass, K. Noack, M. Eichenauer, Mathias Hartmann, Johannes Abel, G. Ganzer, Daniel Lordick","doi":"10.5772/INTECHOPEN.80010","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.80010","url":null,"abstract":"Additional information available at the end of the chapter Abstract The rapid development of additive manufacturing (AM) technologies enables a radical paradigm shift in the construction of heat exchangers. In place of a layout limited to the use of planar or tubular starting materials, heat exchangers can now be optimized, reflecting their function and application in a particular environment. The complexity of form is no longer a restriction but a quality. Instead of brazing elements, resulting in rather inflexible standard components prone to leakages, with AM, we finally can create seam-less integrated and custom solutions from monolithic material. To address AM for heat exchangers we both focus on the processes, materials, and connections as well as on the construction abilities within certain modeling and simulation tools. AM is not the total loss of restrictions. Depending on the processes used, delicate constraints have to be considered. But on the other hand, we can access materials, which can operate in a much wider heat range. It is evident that conventional modeling techniques cannot match the requirements of a flexible and adaptive form finding. Instead, we exploit biomimetic and mathematical approaches with parametric modeling. This results in unseen configura-tions and pushes the limits of how we should think about heat exchangers today.","PeriodicalId":348821,"journal":{"name":"Advances in Heat Exchangers","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127359308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-11-05DOI: 10.5772/INTECHOPEN.80082
Jaafar Albadr
This study investigates experimentally the thermal performance of propylene glycol/ water with a concentration of (10/90) % and Al 2 O 3 /water nanofluid with a volume concentration of (0.1, 0.4, 0.8, 1.5, and 2.5) percentage under turbulent flow inside a horizontal shell and tube heat exchanger. The results indicate that the convective heat transfer coefficient of the nanofluid is higher than the base PG/water for the same inlet tempera- ture and mass flow rates. The heat transfer of the nanofluid increases with the increase in mass flow rate as well as the Al 2 O 3 nanofluid volume concentration. Results also indicate that the increase in the concentration of the particles causes an increase in the viscosity which leads to an increase in friction factor. The effect of Peclet number, Reynolds number, Nusselt number, and Stanton number has been investigated. Those dimensionless number values change with the change in the working fluid density, Prandtl number, and volume concentration of the suspended particles.
{"title":"Thermal Performance of Shell and Tube Heat Exchanger Using PG/Water and Al2O3 Nanofluid","authors":"Jaafar Albadr","doi":"10.5772/INTECHOPEN.80082","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.80082","url":null,"abstract":"This study investigates experimentally the thermal performance of propylene glycol/ water with a concentration of (10/90) % and Al 2 O 3 /water nanofluid with a volume concentration of (0.1, 0.4, 0.8, 1.5, and 2.5) percentage under turbulent flow inside a horizontal shell and tube heat exchanger. The results indicate that the convective heat transfer coefficient of the nanofluid is higher than the base PG/water for the same inlet tempera- ture and mass flow rates. The heat transfer of the nanofluid increases with the increase in mass flow rate as well as the Al 2 O 3 nanofluid volume concentration. Results also indicate that the increase in the concentration of the particles causes an increase in the viscosity which leads to an increase in friction factor. The effect of Peclet number, Reynolds number, Nusselt number, and Stanton number has been investigated. Those dimensionless number values change with the change in the working fluid density, Prandtl number, and volume concentration of the suspended particles.","PeriodicalId":348821,"journal":{"name":"Advances in Heat Exchangers","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123418620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-11-05DOI: 10.5772/INTECHOPEN.78953
M. Picón-Núñez, Jorge C. Melo-González, Jorge L. García-Castillo
Heat transfer enhancement refers to application of basic concepts of heat transfer pro- cesses to improve the rate of heat removal or deposition on a surface. In the flow of a clean fluid through the tube of a heat exchanger, the boundary layer theorem estab - lishes that a laminar sublayer exists where the fluid velocity is minimal. Heat transfer through this stagnant layer is mainly dominated by thermal conduction, becoming the major resistance to heat transfer. From an engineering point of view, heat transfer can be enhanced if this stagnant layer is partially removed or eliminated. In single-phase heat transfer processes, three options are available to increase the heat transfer rate. One of them is the choice of smaller free flow sectional area for increased fluid velocity bring - ing about a reduction of the thickness of the laminar sublayer. A second option is the engineering of new surfaces which cause increased local turbulence, and the third option consists in the use of mechanical inserts that promote local turbulence. The application of these alternatives is limited by the pressure drop. This chapter describes the concept of heat transfer enhancement and the ways it is applied to the development of new heat exchanger technology.
{"title":"Use of Heat Transfer Enhancement Techniques in the Design of Heat Exchangers","authors":"M. Picón-Núñez, Jorge C. Melo-González, Jorge L. García-Castillo","doi":"10.5772/INTECHOPEN.78953","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.78953","url":null,"abstract":"Heat transfer enhancement refers to application of basic concepts of heat transfer pro- cesses to improve the rate of heat removal or deposition on a surface. In the flow of a clean fluid through the tube of a heat exchanger, the boundary layer theorem estab - lishes that a laminar sublayer exists where the fluid velocity is minimal. Heat transfer through this stagnant layer is mainly dominated by thermal conduction, becoming the major resistance to heat transfer. From an engineering point of view, heat transfer can be enhanced if this stagnant layer is partially removed or eliminated. In single-phase heat transfer processes, three options are available to increase the heat transfer rate. One of them is the choice of smaller free flow sectional area for increased fluid velocity bring - ing about a reduction of the thickness of the laminar sublayer. A second option is the engineering of new surfaces which cause increased local turbulence, and the third option consists in the use of mechanical inserts that promote local turbulence. The application of these alternatives is limited by the pressure drop. This chapter describes the concept of heat transfer enhancement and the ways it is applied to the development of new heat exchanger technology.","PeriodicalId":348821,"journal":{"name":"Advances in Heat Exchangers","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130547145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-11-05DOI: 10.5772/INTECHOPEN.76890
Imen Jmal, M. Baccar
Due to their high energy storage capacity, latent heat storage units using phase change materials (PCMs) have gained considerable attention over the past three decades. The heat exchange of a PCM with the surrounding medium is managed by the thermal energy equation (solidification/melting) with different complex boundary and initial conditions. In this study, we propose to solve numerically this equation applied to a PCM by the finite difference method. To understand the storage phenomenon of solar energy in the form of latent heat in PCM, initially found under cooling at 18 (cid:1) C, we studied the fusion in a specific configuration corresponding to a tubular exchanger with five circular horizontal fins. In this perspective, we propose in this work a numerical investigation based on an enthalpy formulation to study the melting of a PCM in a finned heat exchanger. This numerical approach gives simultaneously the temperature distributions in the PCM storage system and temporal propagation of the melting front during the melting of the PCM when it is exposed to a hot airflow. Also, we give in this study the transient evolution of the longitudinal air temperature profiles.
{"title":"Numerical Investigation of PCM Melting in a Finned Tube Thermal Storage","authors":"Imen Jmal, M. Baccar","doi":"10.5772/INTECHOPEN.76890","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.76890","url":null,"abstract":"Due to their high energy storage capacity, latent heat storage units using phase change materials (PCMs) have gained considerable attention over the past three decades. The heat exchange of a PCM with the surrounding medium is managed by the thermal energy equation (solidification/melting) with different complex boundary and initial conditions. In this study, we propose to solve numerically this equation applied to a PCM by the finite difference method. To understand the storage phenomenon of solar energy in the form of latent heat in PCM, initially found under cooling at 18 (cid:1) C, we studied the fusion in a specific configuration corresponding to a tubular exchanger with five circular horizontal fins. In this perspective, we propose in this work a numerical investigation based on an enthalpy formulation to study the melting of a PCM in a finned heat exchanger. This numerical approach gives simultaneously the temperature distributions in the PCM storage system and temporal propagation of the melting front during the melting of the PCM when it is exposed to a hot airflow. Also, we give in this study the transient evolution of the longitudinal air temperature profiles.","PeriodicalId":348821,"journal":{"name":"Advances in Heat Exchangers","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130275507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：