Artykuły w czasopismach na temat „Radiators”
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1
Shui-Chang, Liu, Li Li-Fu i Zhang Yong. "Vehicle Radiators’ Performance Calculation and Improvement Based on the Coupling of Multi-scale Models Simulations". Open Mechanical Engineering Journal 8, nr 1 (31.12.2014): 636–42. http://dx.doi.org/10.2174/1874155x01408010636.
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In simulation of the heat transfer between radiator and air flow field, the adoption of the radiator full-size model containing its core body structure with small feature sizes would require huge storage space and not be economical. In view of this question, based on the coupling of multi-scale models simulations, a calculation method of radiator performance is proposed in this paper the reliability of which is verified by an experiment test. Subsequently, the influence on the radiators’ thermal performance of the layout of the parts in front of the radiators is analyzed. Lastly, the layout of the front parts is modified to enhance the radiators’ thermal performance. The investigation results indicate that: the radiators’ thermal performance calculation method based on simulations coupling of radiator multi-scale models considers the influences of air-side flow field distribution and the core body structure details; the error of the calculating values from the method is less than 5%, and the method is reliable; when the heat source parts in front of the radiators are situated right in front of the rear fan channel, the radiators thermal performance is better; the radiators cooling power increases 19.3kW after layout modification of the front heat resource parts.
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Mar’ina, Z. G., A. Y. Vereshchagin, A. V. Novozhilova, M. A. Komarevtsev i K. O. Isaeva. "Study of the thermal characteristics of the aluminum radiator ROYAL Thermo Evolution". IOP Conference Series: Materials Science and Engineering 1211, nr 1 (1.01.2022): 012005. http://dx.doi.org/10.1088/1757-899x/1211/1/012005.
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Abstract The use of aluminum radiators in heating systems began with the foreign companies products such as Fondital Group, Global Radiatori, Ferroli, etc. There are now Russian aluminum radiators companies that adhere to European standards, for example ROYAL Thermo, Rifar. The thermal characteristics of radiators are usually specified by the manufacturer. However, they are not always confirmed in practice. This is due to the fact that radiator connecting method is not taken into account. In some technical data sheets, the power reduction factors are given depending on the difference between the average coolant temperature and the air temperature in the room. Therefore, the study of the influence of aluminium heating appliances connecting on its thermal characteristics is an actual task. The article presents the results of research of radiator of the ROYAL Thermo Evolution type, it was made on request from company specialising in heating systems design. It was found that the actual thermal power of one section varies in the range of 135 … 225 W, depending on the connection method of the radiator, the thermal power of the section declared by the manufacturer corresponds only to the diagonal «top-bottom» connection, the thermal power of the eight-section radiator with one-sided «top-bottom» connection is 12% higher than with a diagonal one. Studies show, when designing heating systems, it is necessary to take into account the connection method and the number of device sections.
3
Yan, Kai, Feng Li i Jing Ren. "Numerical simulation study on the heat dissipation characteristics of an air-cooled radiator". E3S Web of Conferences 441 (2023): 03013. http://dx.doi.org/10.1051/e3sconf/202344103013.
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This article conducts numerical simulation calculations on the heat dissipation characteristics of an air-cooled radiator. The results show that under natural heat dissipation conditions, the maximum temperature of air-cooled radiators with flat heat dissipation covers decreases by 9.6% compared to radiators without heat dissipation covers, and the maximum temperature of air-cooled radiators with array raised heat dissipation covers decreases by 9.9%; Under forced air cooling conditions, the maximum temperature of an air-cooled radiator with a flat heat dissipation cover decreases by 12.7%, while the maximum temperature of an air-cooled radiator with an array raised heat dissipation cover decreases by 13.3%.
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Sravan, Venapusa, Himani Srivastava, Pandey DHANRAJ Jitendra i S. Senthur Prabu. "Investigation on Thermal Analysis of Spacecraft Radiators". ECS Transactions 107, nr 1 (24.04.2022): 17073–83. http://dx.doi.org/10.1149/10701.17073ecst.
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In this research, the main objective is to compare the thermal properties of the rectangular and honeycomb structured space radiators used in spacecraft. The comparison of radiators was done by conducting steady state thermal analysis on these radiators by applying varying heat loads over it to analyse the thermal properties acting over them. The selection of appropriate material for the radiators was based on tensile strength, resistance to high temperature, and the type of working fluid considered. From the simulation results, the honeycomb structures of spacecraft radiator could withstand to a higher temperature gradient, and the rate of heat dissipation was much higher in comparison with rectangular fin type radiator, and hence it can be considered as a great replacement in near future.
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Dzierzgowski, Mieczysław. "Verification and Improving the Heat Transfer Model in Radiators in the Wide Change Operating Parameters". Energies 14, nr 20 (12.10.2021): 6543. http://dx.doi.org/10.3390/en14206543.
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Laboratory measurements and analyses conducted in a wide range of changes of water temperature and mass flow rate for different types of radiators allowed to provides limitations and assessment of the current radiators heat transfer model according to EN 442. The inaccuracy to determinate the radiator heat output according to EN 442, in case of low water mass flow rates may achieve up to 22.3% A revised New Extended Heat Transfer Model in Radiators NEHTMiRmd is general and suitable for different types of radiators both new radiators and radiators existing after a certain period of operation is presented. The NEHTMiRmd with very high accuracy describes the heat transfer processes not only in the nominal conditions—in which the radiators are designed, but what is particularly important also in operating conditions when the radiators water mass flow differ significantly from the nominal value and at the same time the supply temperature changes in the whole range radiators operating during the heating season. In order to prove that the presented new model NEHTMiRmd is general, the article presents numerous calculation examples for various types of radiators currently used. Achieved the high compatibility of the results of the simulation calculations with the measurement results for different types of radiators: iron elements (not ribbed), plate radiators (medium degree ribbed), convectors (high degree ribbed) in a very wide range of changes in the water mass flow rates and the supply temperature indicates that a verified NEHTMiRmd can also be used in designing and simulating calculations of the central heating installations, for the rational conversion of existing installations and district heating systems into low temperature energy efficient systems as well as to directly determine the actual energy efficiency, also to improve the indications of the heat cost allocators. In addition, it may form the basis for the future modification of the European Standards for radiator testing.
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Jiang, C. H., i T. Y. Kam. "Vibration and Sound Radiation Characteristics of Composite Flat-Panel Sound Radiator". Applied Mechanics and Materials 431 (październik 2013): 177–81. http://dx.doi.org/10.4028/www.scientific.net/amm.431.177.
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The vibration and sound radiation characteristics of laminated composite flat-panel sound radiators are studied via both theoretical and experimental approaches. In the theoretical study, a finite element model is presented to formulate the forced vibration of the sound radiators. The first Rayleigh integral is used to construct the sound pressure level curve of the sound radiators. In the experimental study, a laminated composite sound radiator was subjected to sweep sine excitation to determine the frequency response spectrum from which the natural frequencies of the sound radiator were identified. The sound radiator with salt powder distributed on its top surface was excited to generate the vibration shapes of the sound radiator at several selected frequencies. The SPL curve of the sound radiator was also measured experimentally. The experimental results are then used to verify the feasibility and accuracy of the proposed finite element model.
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BARGŁOWSKI, Leszek, Mariusz ADAMSKI i Maksym REBMAN. "ANALYSIS OF STRUCTURAL SOLUTIONS FOR RADIATORS IN BUILDINGS". Civil and Environmental Engineering Reports 33, nr 1 (8.09.2023): 139–49. http://dx.doi.org/10.59440/ceer-2023-0010.
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In the following article emphasizes the analysis of technical and economic criteria for radiators, that will help you make the right choice of radiator type. Different solutions for heating flats are presented, the focus is on water-fed radiator solutions. After detailed analysis, the evaluation criteria are selected: indicators of the unit heat output of a radiator related to the mass, volume and length of the radiator QM, QV, QL. Radiator types, nominal working parameters, evaluations criteria and techno-economic analysis of structural solutions for radiators on the example of a residential building are presented.
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Soloveva, Olga, Sergei Solovev, Rozalina Shakurova i Timur Mustafaev. "Numerical simulation of dust particle deposition and heat transfer in fin-plate radiators". E3S Web of Conferences 460 (2023): 08006. http://dx.doi.org/10.1051/e3sconf/202346008006.
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Fin-plate radiators are actively used in cooling systems for microelectronic devices. Radiators often become dusty during operation, which leads to decrease in heat flow and heat dissipation. Consequently, the possibility of device overheating and failure increases. We carried out numerical studies to assess the influence of the radiator geometry on the deposition of dust particles and, as a consequence, the change in heat flow. We built 3D models of plate radiators with different types of fins (flat and corrugated) and the distance between them. The problem of air flow with dust particles flowing around the radiator has been solved. We revealed the dependences of the efficiency of particle deposition and changes in heat flow on the geometry of the radiator, the size of dust particles and the distance between the fins.
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Bupesh Raja, V. K., R. Unnikrishnan i R. Purushothaman. "Application of Nanofluids as Coolant in Automobile Radiator – An Overview". Applied Mechanics and Materials 766-767 (czerwiec 2015): 337–42. http://dx.doi.org/10.4028/www.scientific.net/amm.766-767.337.
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In this paper a literature review is made on the application of nanofluids as coolant in automobile radiators. The nanoparticles by virtue of their smaller size possess more surface area than the bulk material, which shall enable them to absorb and dissipate heat at a faster rate. Generally water and ethylene glycol are used as coolants in automobile radiators. Several investigators have used nanofluids consisting of nanosize particles of TiO2, Al2O3, SiO2, CuO, Fe2O3, etc., suspended in the coolant used in the radiator of automobiles. These investigators have observed that the application of nanofluids increases the cooling rate and shall pave way for reducing the weight and size of the radiator, there by contributing to smaller and efficient radiators.
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Liu, Zongjiang, Wei Xu, Linhua Zhang, Zhong Li i Airong Feng. "Research on improving the overall thermal performance of panel radiators based on the CFD method". Journal of Physics: Conference Series 2592, nr 1 (1.09.2023): 012026. http://dx.doi.org/10.1088/1742-6596/2592/1/012026.
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Abstract A panel radiator is one of the radiators commonly used in central heating at present. Improving the heat performance of the panel radiator and making it more suitable for low-temperature heating is an important direction of current research on heating energy conservation. This paper studied the overall heat transfer performance of panel radiators based on the CFD method. The research shows that compared with the longitudinal continuous fin widely used at present, the use of discontinuous fins and staggered fins can improve the thermal properties of the panel radiator significantly. The comparative study of eight scenarios shows that the average heat transfer coefficient of the radiator equipped with longitudinal staggered fins and VGs increases by 120.24%, and the radiator equipped with discontinuous inclined staggered fins increases by 117.33%. Due to the reduction of heat dissipation area, the total amount of heat dissipation of the radiator equipped with discontinuous fins is not as good as the radiator equipped with staggered fins that does not change the heat dissipation area basically. This study provides a way to improve the heat transfer properties of panel radiators.
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Kroulíková, Tereza, Tereza Kůdelová, Erik Bartuli, Jan Vančura i Ilya Astrouski. "Comparison of a Novel Polymeric Hollow Fiber Heat Exchanger and a Commercially Available Metal Automotive Radiator". Polymers 13, nr 7 (6.04.2021): 1175. http://dx.doi.org/10.3390/polym13071175.
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A novel heat exchanger for automotive applications developed by the Heat Transfer and Fluid Flow Laboratory at the Brno University of Technology, Czech Republic, is compared with a conventional commercially available metal radiator. The heat transfer surface of this heat exchanger is composed of polymeric hollow fibers made from polyamide 612 by DuPont (Zytel LC6159). The cross-section of the polymeric radiator is identical to the aluminum radiator (louvered fins on flat tubes) in a Skoda Octavia and measures 720 × 480 mm. The goal of the study is to compare the functionality and performance parameters of both radiators based on the results of tests in a calibrated air wind tunnel. During testing, both heat exchangers were tested in conventional conditions used for car radiators with different air flow and coolant (50% ethylene glycol) rates. The polymeric hollow fiber heat exchanger demonstrated about 20% higher thermal performance for the same air flow. The efficiency of the polymeric radiator was in the range 80–93% and the efficiency of the aluminum radiator was in the range 64–84%. The polymeric radiator is 30% lighter than its conventional metal competitor. Both tested radiators had very similar pressure loss on the liquid side, but the polymeric radiator featured higher air pressure loss.
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Kushchev, L. A., V. N. Melkumov, N. Yu Savvin i V. V. Chuiko. "Simulation of heat Carrier Motion in Tubular Heating Radiators". Russian Journal of Building Construction and Architecture, nr 2(58) (15.05.2023): 25–33. http://dx.doi.org/10.36622/vstu.2023.2.58.003.
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Statement of the problem. The movement of the coolant in sections of tubular heating radiators of original designs containing various types of turbulators is considered. It is necessary to develop models of the movement of the coolant in the structures under consideration in the speed range of 0.5—1.5 m/s and compare the intensity of flow turbulence in them. Results. Using the Flow Simulation module of the SOLIDWORKS software package, the results of modeling the movement of a coolant in sections of original tubular heating radiators with turbulent inserts were obtained. 3D models of radiator sections were built. The dependences of the Re number on the coolant velocity and the distribution of turbulence intensity in the radiator sections are given. Conclusions. Based on the results of the simulation, the designs of the sections of the original tubular heating radiators were compared with the standard ones. A turbulent insert providing the highest Re number and turbulence intensity in the radiator section has been determined.
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Khan, Muhammad Saeed, Adnan Iftikhar, Raed M. Shubair, Antonio-Daniele Capobianco, Sajid Mehmood Asif, Benjamin D. Braaten i Dimitris E. Anagnostou. "Ultra-Compact Reconfigurable Band Reject UWB MIMO Antenna with Four Radiators". Electronics 9, nr 4 (30.03.2020): 584. http://dx.doi.org/10.3390/electronics9040584.
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A compact reconfigurable UWB MIMO antenna with four radiators that accomplish on-demand band rejection from 4.9 to 6.3 GHz is presented. An LC stub is connected to the ground plane by activating the PIN diode for each radiator. Two radiators are placed perpendicular to each other to exploit the polarization diversity on a compact 25 × 50 mm 2 FR4 laminate. Two additional radiators are then fixed obliquely on the same laminate (without increasing size) in angular configuration at ±45 ∘ perpendicular to the first two planar radiators still exploiting polarization diversity. The design is validated by prototyping and comparing the results with the simulated ones. On demand band rejection through the use of PIN diodes, wide impedance matching (2–12 GHz), high isolation amongst the radiators, compactness achieved by angular placement of the radiators, low gain variation over the entire bandwidth, band rejection control achieved by adjusting the gap between stub and ground plane, and low TARC values makes the proposed design very suitable for commercial handheld devices (i.e., Huawei E5785 and Netgear 815S housings). The proposed configuration of the UWB MIMO radiators has been investigated first time as per authors’ knowledge.
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Pan, Yuhui, Hua Chen, Yitao Shen i Wenlong Cheng. "Experimental study on the flow and heat transfer characteristics of pin-fin manifold microchannel heat sink". Journal of Physics: Conference Series 2683, nr 1 (1.01.2024): 012031. http://dx.doi.org/10.1088/1742-6596/2683/1/012031.
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Abstract A manifold microchannel radiator with a cylindrical pin-rib microchannel is designed and fabricated to enhance the heat dissipation capability of the manifold microchannel radiator, and its flow and heat dissipation capability are investigated by experiments. The fabrication and experiment of the manifold pin-rib microchannel radiators are introduced in detail. The heat dissipation capability of manifold pin-rib microchannel radiators at different flow rates is compared. The result shows that the manifold pin-rib microchannel radiator has excellent heat dissipation performance. When HFE7100 is used as the working medium, the average heated surface temperature of the manifold pin-rib microchannel radiator is about 100°C at the thermal flux density of 1000 W/cm2.
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Matzner, H., i E. Levine. "Can Radiators Be Really Isotropic?" International Journal of Antennas and Propagation 2012 (2012): 1–9. http://dx.doi.org/10.1155/2012/187123.
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In search for isotropic radiators with reasonable quality Factor (Q), bandwidth, and efficiency, one looks for practical radiators with a typical resonant length of . We present here a Green's function analysis in Fourier of a microstrip element and a far-field integral method in configuration (real) space of single and dual U-shaped elements. Both solutions analytically prove that the power radiation patterns are isotropic in nature (while the thickness and the width tend to zero), although the polarizations are not symmetrical in all cuts. It is also shown that the power isotropic U-shaped radiator, for which the surface current density is infinite, can be replaced by another finite-size radiator, having finite-surface current density, such that its far-field is exactly the same as the far-field of the U-shaped isotropic radiator.
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Gilmanova, Alfiya, Oleg Filimonov, Irida Galiullina, Eduard Mukhamadeev i Elena Guseinova. "On the development of the emitter assembly of an acoustic downhole device". E3S Web of Conferences 524 (2024): 03034. http://dx.doi.org/10.1051/e3sconf/202452403034.
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The article considers narrow-band and broadband variants of the acoustic logging method, shows the advantages and disadvantages of existing radiators, describes the requirements for acoustic radiators of borehole devices for a wide frequency range from 0.5 to 40 kHz, shows the experimental and theoretical justification of the designs of radiator assemblies and the basic requirements for calculations. The result of the work is an upgraded design of the radiator assembly, which ensures the operation of broadband acoustic logging devices, described in detail in this article.
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Sonia, Pankaj, Rakesh Chandrashekar, Nibras Hayder, K. Sunil Kumar Reddy, Sorabh Lakhanpal, Deepika Arora i N. E. Chandra Prasad. "Thermal Analysis of Radiator Using Sustainable Graphene oxide Nanofluid Mixture of Ethylene Glycol and Water". E3S Web of Conferences 552 (2024): 01103. http://dx.doi.org/10.1051/e3sconf/202455201103.
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The purpose of the research is to determine if adding grapheme oxide (GO) fluids combined with EG (ethylene glycol) or water might boost the transfer of heat in automobile radiators. Radiators are essential parts of car cooling systems; they dissipate extra heat that the engine produces. The capacity of conventional coolants to transport temperature is limited, including Glycol and water. The ability to conduct heat may be improved with the use of nanoparticles fluids, which are basically solutions of particles in a base liquidize. This technique uses ethylene glycol and water to create a nanoparticles fluid by dispersing GO particles. Using experiments, the resilience or thermal features of the nanoparticle fluids are described. Next, utilizing an early version radiators arrangement, many heat transfer tests are carried out. In comparison to traditional coolants, the radiator’s ability to dissipate heat in various functioning circumstances has been assessed while utilizing the GO nanoparticles fluids together. Comparing the radiator’s heat transfer efficiency with plain ethylene glycol (or water, initial results indicate the addition with GO nanoparticles fluids improves it. Increased thermal conductivity in the nanoparticles fluids combination results in more efficient heat dissipation. For the purpose of to ensure the efficient utilization of the nanoparticles fluids on car cooling mechanisms, it is further evaluated for durability during extended exposure to elevated temperatures. The continued attempts to provide cutting-edge cooling systems for automotive applications are aided by this study. The results indicate that the use of GO nanoparticles fluids in conjunction with conventional coolants has a chance to improve car radiator thermal transfer or general efficiency. It is advised to carry out greater refinement and calibration research to fully realize the potential advantages of this unique coolant composition.
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Wang, Xin Ting, Jun Xia Zhang i Li Ping Yin. "Research of Electric Radiator Design Based on DFMA Method". Applied Mechanics and Materials 313-314 (marzec 2013): 11–14. http://dx.doi.org/10.4028/www.scientific.net/amm.313-314.11.
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Aimed at optimizing electric radiators design process, the enterprises expectationsmanufacturing technologies and market developing status were analyzed, then electric radiators key design restraining factors were summarized, design orientation was proposed finally. Based on this premise, a block-based electric radiator design scheme was presented with the Design For Manufacture & Assembly method (DFMA), then taking electric radiators key structure and part as an example , the application of DFMA in design practice was discussed in the view of coordinating the relation of product styling effect and structure design. Practices show that DFMA method is beneficial to improve design efficiency and feasibility.
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Ptitsyna, Elena, Alexander Kuvaldin i Dmitry Ptitsyn. "The effective modes of infrared radiators and heating systems". E3S Web of Conferences 140 (2019): 04005. http://dx.doi.org/10.1051/e3sconf/201914004005.
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The authors have been researching the effect of polyharmonic currents (complex waveform current) on the characteristics of different types of radiators for a few years. These researches have shown an increase in the energy efficiency of installations with dark and light radiators and the ability to control the harmonic composition of radiation. It is important considering the need to harmonize the frequency characteristics of a radiator with the frequency response of an energy absorbing surface. The object of experimental research are flexible heating tape and installations with dark radiators and their joint operation modes when powered by complex waveform current from a common power source. The purpose of the work is the definition of characteristics of the flexible heating tape and dark infrared radiators when changing the amplitude and frequency of the supply voltage to develop recommendations for the selection of effective modes.
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Vadiee, Amir, Ambrose Dodoo i Elaheh Jalilzadehazhari. "Heat Supply Comparison in a Single-Family House with Radiator and Floor Heating Systems". Buildings 10, nr 1 (30.12.2019): 5. http://dx.doi.org/10.3390/buildings10010005.
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Floor heating and radiators are two of the most common types of hydronic heating systems used for space heating in single-family houses in cold climate regions. Notwithstanding, there are few comparative studies on indoor temperature distribution and system cost evaluations for radiators and floor heating. Furthermore, there are no aligned outcomes in terms of total heat supply for a single-family house with radiators or floor heating. In this study, the effect of building energy efficiency level and construction type, including flooring material, on the supply heating demand and transmission heat losses were studied for both radiator and floor heating systems. For this purpose, a single-family house located in Växjö, Sweden, was modeled as a case study. The heating demand was supplied with a district heating system with a similar supply temperature at 45 °C for both the radiator and floor heating system. A sensitivity analysis was also performed to assess the effect of flooring configurations on the annual supply heating demand for both conventional and passive versions of the case-study building. The results showed that the radiator-integrated building had a lower supply heating demand in comparison with the floor heating-integrated buildings. Based on the sensitivity studies, the flooring material did not have a significant influence on the supply heating demand and on the transmission heat losses in the case of the radiators. The supply heating demand was only reduced up to 3% if the flooring U-value was improved by 60%. The results also showed that refurbishment in a standard conventional building with a radiator heating system based on the passive criteria led to a 58% annual energy savings, while this amount for a building with a floor heating system was approximately 49%.
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Kudryashov, M. A., O. A. Belousov, V. I. Tetyukhin, M. M. Kiryupin, V. P. Belyaev, I. V. Nagornova i E. G. Bezzateeva. "Development of antenna system for use in meteorological and climatic control complexes". Journal of Physics: Conference Series 2182, nr 1 (1.03.2022): 012094. http://dx.doi.org/10.1088/1742-6596/2182/1/012094.
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Abstract The synthesis of a cylindrical antenna array for ground-based mobile weather monitoring complexes, based on quadrifilar radiators, is considered. The basic mathematical expressions for determining the electrodynamic characteristics of both the radiator from the antenna array and the AA itself are presented. Various phenomenological models of these radiators are considered. The approach to the synthesis of phenomenological models of the radiator and antenna array as a whole is described. The results of such synthesis are given, and the main characteristics and values of DG, CG, SWR, RP for the given type of radiator and AA in the corresponding frequency range are obtained. Techniques for using phenomenological models for operational synthesis of electrodynamic structures such as cylindrical AA and quadrifilar radiator are developed and described in detail. The possibility of applying this approach to the synthesis of this type of structures for radar weather monitoring systems is shown.
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Chen, Liguo, i Bjørn Reidar Sørensen. "Modelling Multi-layer Hydronic Radiators". E3S Web of Conferences 172 (2020): 12007. http://dx.doi.org/10.1051/e3sconf/202017212007.
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This report simulates Purmo type C22 and C33 radiators with both standard calculation and heat transfer method with help of Matlab/Simulink. Simulation results are presented to describe the radiators’ thermal performances with different simulation strategies. The deviations between two different calculation methods are identified and the heat transfer radiator model can be improved with more investigations regarding thermal dynamics and controlling strategy. Under simulation scenarios of simple room model with a PID controller, type C33 has shorter response time and faster stabilization of room temperature; and it has lower outflow temperature, which implies higher energy efficiency.
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Ta, Son Xuat, Kam Eucharist Kedze, Dao Ngoc Chien i Ikmo Park. "Bandwidth-Enhanced Low-Profile Antenna with Parasitic Patches". International Journal of Antennas and Propagation 2017 (2017): 1–11. http://dx.doi.org/10.1155/2017/6529060.
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This paper presents low-profile broadband antennas, which are composed of four parasitic patches placed between planar radiators and a perfect electric conductor ground plane. Two types of planar radiators, a conventional dipole and a crossed dipole, are employed to produce linearly polarized (LP) and circularly polarized (CP) radiations, respectively. The radiator and parasitic patches are realized on thin substrates to lower the cost. Owing to the presence of parasitic patches, the antenna performance improves in terms of profile reduction, resonant frequency decrease, and bandwidth enhancement. These improvements are discussed and confirmed computationally and experimentally. The LP design with the overall dimensions of 120 mm × 120 mm × 16.3 mm (0.64λ0 × 0.64λ0 × 0.087λ0 at 1.6 GHz) has a |S11| < −10 dB bandwidth of 1.465–1.740 GHz (17.2%), a broadside gain of 8.5–8.8 dBi, and a radiation efficiency > 96%. The CP design, which has the same physical size as the LP case, has a |S11| < −10 dB bandwidth of 1.388–1.754 GHz (23.3%), a 3 dB AR (axial ratio) bandwidth of 1.450–1.685 GHz (15.0%), a right-hand CP broadside gain of 7.8–8.7 dBic, and a radiation efficiency > 90%.
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Puttige, Anjan Rao, Kailun Feng, Weizhuo Lu i Thomas Olofsson. "Are radiators ready for the challenges of the future: A review of advancements in radiators". E3S Web of Conferences 356 (2022): 03024. http://dx.doi.org/10.1051/e3sconf/202235603024.
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Radiators play an important role in providing a comfortable and safe indoor environment while maintaining high-energy efficiency. In the perspective of future climate change with expected larger temperature fluctuations and the rapidly changing heat supply and demand, it is required that the current radiator technology is adaptable. The heat supply is changing towards a lower supply temperature to enable an increase in energy efficiency and an increase in the share of renewable energy. Simultaneously, both the heat supply and demand are expected to have more variations in the future. An additional concern that has come into more focus after the experience with the COVID 19 pandemic is the prevention of the spread of infection in indoor environments. Researchers have extensively studied several innovations in radiator technologies and their deployment that addresses these challenges. Some of the solutions available in the literature include floor heating, ceiling heating, ventilation radiator, stratum ventilation. Researchers have used advanced modeling and experimental techniques to understand how to deploy different types of radiator technologies. This review summarizes solutions in the literature that address these challenges and identifies knowledge gaps that need to be addressed. In particular, this study explores the gaps in knowledge of practical issues, such as the position of furniture and the position of people, which have received less attention in the literature. Research that addresses the effect of radiators on ventilation and a healthy indoor environment is also of particular interest in this review.
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Michalczyk, J. "The Development and Numerical Analysis of the Conical Radiator Extrusion Process". Archives of Metallurgy and Materials 62, nr 4 (1.12.2017): 2267–72. http://dx.doi.org/10.1515/amm-2017-0334.
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Abstract The article presents a newly developed method for single-operation extrusion of conical radiators. This is the author’s radiator manufacturing method being the subject of a patent application. The proposed method enables the manufacture of radiators either with or without an inner opening and with an integral plate. Selected results of numerical computations made within Forge®3D, a finite element method (FEM)-based software program, were presented during the analysis of the process. A comparative analysis of the proposed manufacturing method using the double-sided extrusion method was also made. The proposed manufacturing method is assumed to produce radiators in a single technological operation with the stock material being standardized 30 mm-diameter aluminium bars. The objective of the developed method is also to reduce the energy-force parameters.
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Liu, Zongjiang, Linhua Zhang, Wei Xu, Zhong Li i Airong Feng. "Heating performance enhancement in panel-type radiators based on vortex generators and fin form optimization". Journal of Physics: Conference Series 2592, nr 1 (1.09.2023): 012030. http://dx.doi.org/10.1088/1742-6596/2592/1/012030.
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Abstract Increasing the heat performance of heating radiators could be a valuable method for building energy conservation. This paper studied the influence of fins on the thermal performance of panel radiators (type 11). The effect of different vortex generator angles, the gap width of discontinuous fins, and different forms of staggered fins have been studied numerically and experimentally. Firstly, the simplified model of the panel radiator was analyzed by CFD simulation, the thermal performance under different geometric parameters was studied, and better geometric parameters were obtained. Research shows that optimizing the parameters of the vortex generator has a positive effect in increasing the heat dissipation of the radiator. Both discontinuous fins and staggered fins can improve the thermal performance of the radiator. The research shows that the fin shape has a significant impact on the heat dissipation of the radiator. The thermal performance of the radiator can be greatly improved by using a vortex generator with specific angles, staggered fins, and discontinuous fins. These technical routes can be directly implemented on the basis of the original radiator, which provides a direction for the technical improvement of this type of radiator.
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Ravigururajan, T. S., i M. L. Goryca. "An Experimental Verification of a Conceptual Heat-Pipe Radiator". Journal of Energy Resources Technology 115, nr 4 (1.12.1993): 272–77. http://dx.doi.org/10.1115/1.2906432.
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The radiator and its vulnerability to damage is one of the main criteria in automotive design. This study employed heat pipes in simulated radiators to transfer waste heat to the surrounding environment. A small-scale heat-pipe radiator module was designed using a computer program. Experimental tests were performed on this module to validate the design methodology and to study the vulnerability characteristics. The tests were conducted for a wide range of operating parameters such as air velocity, coolant flow rates, and the number of heat pipes damaged. The study indicated that a heat-pipe radiator may provide the necessary “limp home” capability to a vehicle, even with 50 percent of the pipes damaged. Also, with the radiators operating at less than peak load (slower vehicle speed), the undamaged heat pipes substantially compensated for the damaged heat pipes, adding to the reliability of the system.
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Vishwakarm, Yogesh, Nibras Hayder, Tummala Srinivas, Anandhi R J, Alok Jain, Shashi Prakash Dwivedi i Ch Ravi Kiran. "CFD Analysis of using Deionized Water in Radiator to Enhance the Efficiency for Sustainable Growth". E3S Web of Conferences 552 (2024): 01107. http://dx.doi.org/10.1051/e3sconf/202455201107.
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Conventional liquid coolant used in automotive radiators is often used as an engine coolant. Heating systems in automotive air chambers are commonly used to cool circulating fluids, usually water or an aqueous combination of antifreeze agents such as ethylene glycol (EG). This study examines the benefits and issues of the usage of deionized water in all radiators. Deionized (DI) water has received attention as a possible alternative to chemical coolants generally used in automobile air conditioners. Automotive engineers are addressing the demanding situations of intense freezing by developing special garage systems to optimize engine overall performance and limit environmental impact. Compared to conventional refrigerants, the usage of deionized water has lesser environmental consequences, consisting of decreased corrosion and mineral production, which extends radiator lifestyles and improves cooling efficiency. Moreover, DI-water poses several challenges, which include the capability to freeze and compatibility with some radiator materials. Ultimately, this study investigates using deionized water as a refrigerant while used in radiators inside the inlet water. Additionally, it explores the impact of deionized water on engine performance, durability, heat transfer overall performance, corrosion resistance, and potential overheating, at the same time as additionally addressing environmental problems.
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Šikula, Ondřej, Pavel Charvát, Lahouari Adjlout i Omar Ladjedel. "Modeling of Radiators with Mass Flow Control". Applied Mechanics and Materials 887 (styczeń 2019): 667–75. http://dx.doi.org/10.4028/www.scientific.net/amm.887.667.
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The topic of the contribution can be included in computer modeling of the thermal behavior of radiators for heating of buildings. Control of heaters leads to dynamic phenomena affecting the final thermal state of the heated room and heating energy consumption. The paper focuses on modeling of radiator quantitative control method using thermostatic valve. The objective of the paper is to show a quality of controlling and to compare an energy consumption when various thermostatic radiator valves time delay are set. The models of control, radiator, and a room are implemented in software TRNSYS. The results show significant differences in energy consumption.
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Cho, Jeongmin, Tae Heung Lim, Youngwan Kim i Hosung Choo. "Design of a Wideband Printed Patch Dipole Antenna with a Balanced On-Board Feeding Network". Journal of Electromagnetic Engineering and Science 22, nr 6 (30.11.2022): 631–37. http://dx.doi.org/10.26866/jees.2022.6.r.132.
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This paper proposes a wideband printed patch dipole antenna with a simple on-board feeding network. The proposed antenna is composed of two dipole radiators, a transmission line, and an on-board feeding network with a chip balun. The dipole radiators are printed on a substrate, and the edges of the radiators are truncated to create a hexagonal shape with wide impedance-matching characteristics. The chip balun is embedded in an RO4003C printed circuit board (PCB) to excite differential feeding to each radiator with a 180° phase difference. The proposed antenna is optimized using a CST Studio full electromagnetic software tool, and it is fabricated and measured in an anechoic chamber. The measured fractional bandwidth for the reflection coefficient below –10 dB is 79.5%, and the proposed antenna has a measured gain of 7.1 dBi at 3.5 GHz.
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Alekseytsev, S. A., D. A. Bukhtiyarov, A. P. Gorbachev, Yu N. Parshin i N. V. Tarasenko. "Printed dual-band end-feed dipole radiators". Journal of «Almaz – Antey» Air and Space Defence Corporation, nr 4 (30.12.2019): 35–42. http://dx.doi.org/10.38013/2542-0542-2019-4-35-42.
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The study describes a new dual-band dipole printed radiator, which is part of an integrated module that contains a strip-slotted balun, whose outputs are first connected to the remote ends of both halves of the dipole radiator. We examine the features of its structural implementation, layout and technological performance, and give optimized geometric parameters of the printing module. The experimental results verify the proposed approach and serve as evidence of the acceptability of the obtained operating characteristics of the radiators.
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Liu, Chuan Bo, i Li Ming. "Research and Optimization on the Louvered Fin Height for Subcompact Radiator". Applied Mechanics and Materials 48-49 (luty 2011): 906–10. http://dx.doi.org/10.4028/www.scientific.net/amm.48-49.906.
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To get more appropriate louvered fin structure of a series of subcompact radiators, Fluent was used to analyze the subcompact radiator louvered fins numerically. The fin model was verified availably by testing the error between the simulation results and experimental ones. Through modifying the critical dimension of louvered fin models, the friction factor f and the heat factor j of subcompact radiator louvered fins under different fin height were obtained. The regression analysis indicated that the friction factor was linear with fin height, and the heat factor was the power function of fin height. The dimensionless parameter j/f1/3was introduced to evaluate the comprehensive performance of fins, and the research indicated that the performance would be best when the fin height was 8.94mm. The result has a certain practical value for improving the performance of subcompact radiators.
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Tuomas, Edvardas, i Saulius Neverbickas. "METHODOLOGY OF THE PRIMARY DATA RECONSTRUCTION OF SINGLE PIPE HEATING SYSTEMS/VIENVAMZDŽIŲ ŠILDYMO SISTEMŲ PIRMINIŲ DUOMENŲ NUSTATYMO METODIKA". JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 5, nr 5 (31.10.1999): 318–22. http://dx.doi.org/10.3846/13921525.1999.10531482.
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The majority of dwellings in Lithuania are situated in blocks of flats. The dwellings were built after World War II and they are heated by single pipe central heating systems, connected to district heating. The dwellers are not quite satisfied with such a heating system and try to improve it, but do that in a wrong way, by increasing the surface of radiators. Such means lead to violation of thermal regime and comfort conditions for other dwellers. There exists sometimes the necessity of reconstructing premises and together—the heating system. During the reconstruction the primary heat fluxes from radiators should be known, but very often such data are lost and only the size of radiators (number of sections) are known. To reconstruct the required primary data for single pipe systems is complicated because the temperatures of inlet and outlet water for radiators are unknown. In this article the methodology is proposed how to perform the calculations leading to the required data. The aim of calculations is the establishment of heat fluxes from each radiator connected to the riser. Heat flux from radiator can be calculated according the formula (1) but the complex coefficient is unknown. It could be found from formulae (2) but some magnitudes are unknown. According to the proposed methodology the values of unknown magnitudes are taken approximately and calculations are performed with iterations. In such a way the flow rate of water in riser is established from formula (3), which is the same for each radiator (the property of single pipe system). From formulas (3) and (4) an equation is produced (5), and is used for calculations of unknown temperatures. The equation (6) is used for calculation of heat fluxes from radiators. To carry out the above-mentioned calculations without computer practically is impossible due to many cycles of iteration. The programme was prepared to make easy all these calculations. The scheme of algorithm of programme is given in Fig 1. An example of calculation is given in this article. Calculations were fulfilled by newly created programme. The riser chosen for calculation is shown in Fig 2. The results of calculation are given in Table 1. The table shows that according to the proposed methodology the programme based on it can be used for reconstruction of primary data of single pipe heating systems successfully.
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Si, Wenrong, Shanshan Jin, Yiru Shou, Peng Yuan, Yuhang Tian i Jian Yang. "Numerical study of cooling performance augmentation for panel-type radiator under the chimney effect". Thermal Science, nr 00 (2024): 76. http://dx.doi.org/10.2298/tsci230926076s.
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In order to augment cooling performance of transformer panel-type radiators under natural convection, the fluid flow and heat transfer for a novel panel-type radiator and its surrounding air are numerically studied in this paper. The novel radiator is equipped with wind deflectors on both lateral sides and a chimney cap on the top. Then the effects of the height and channel number of the chimney cap on the cooling performance of the radiator are simulated. The results show that wind deflectors can form several enclosed air channels with radiator fins. The airflow can be accelerated under the chimney effect generated in these channels, and the cooling capacity of the radiator can be increased by 12.75%. The addition of a chimney cap can further extend the chimney channels and increase its cooling capacity by 15.74%. Furthermore, with the increase of the height and channel number, the total cooling capacity of the panel-type radiator increases first and then decreases. In this study, when the chimney cap has five channels and a height of 700 mm, the novel radiator can obtain the best cooling performance, where its cooling capacity and overall heat transfer coefficient can be increased by 26.54% and 28.21%, respectively, as compared with traditional panel-type radiators, and the temperature difference between the inlet and outlet insulating oil is 7.1?C.
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Caturwati, Ni Ketut, Yusvardi Yusuf i Muhammad Ilham Al Faiz. "(Performance of Gas Turbine Cooling System (Radiator) at PLTGU XYZ against Environmental Air Temperature)". R.E.M. (Rekayasa Energi Manufaktur) Jurnal 5, nr 1 (12.01.2021): 15–21. http://dx.doi.org/10.21070/r.e.m.v5i1.889.
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The heat exchanger is an important component in the gas and steam power plant (PLTGU) industry. One of the most important heat exchangers in gas turbine cooling systems is the gas turbine radiator. The gas turbine radiator functions to cool the cooling water, which circulated to various components of the gas turbine by using environmental air as the cooling medium. The purpose of this study was to determine the effect of environmental temperature on the performance of gas turbine radiators and to compare operational data in 2017 with operational data when the study conducted in 2019. Data collected for 3 days with 2-3 hour intervals. Data processing and analysis shows that the higher the ambient temperature, the higher the radiator effectiveness value. Data in 2017 shows the highest average value of effectiveness obtained at an ambient air temperature of 35 ˚C of 71,274%. Meanwhile, data in 2019 shows the highest average value of effectiveness at an ambient air temperature of 35 ˚C of 58,859%. Thus, the average effectiveness value of gas turbine radiators has decreased by 12,415% from 2017 to 2019
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Han, Yue, Ya Jun Zhang, Da Ming Wu, Jian Zhuang i Kai Fang Dang. "Optimal Design of Micro Plastic Heat Radiator". Key Engineering Materials 503 (luty 2012): 67–70. http://dx.doi.org/10.4028/www.scientific.net/kem.503.67.
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A new type of plastic micro heat radiators is designed in this paper. The radiator is prospected to be used in electronic system, chemical engineering system, etc. It is made of modified Phenylene sulfide with high thermal conductivity. A series of numerical simulations are carried out to optimize the structure of the radiator. The structure of the radiator includes the thickness of the fin and the distance between fins. The results show that the performance of the micro plastic heat radiator is very close to that of the metal heat radiator with the same dimension.
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Hao, Gai Hong, i Ya Ping Zhang. "Thermal Performance Simulation of the Metal Foam Heat Sink". Solid State Phenomena 298 (październik 2019): 208–13. http://dx.doi.org/10.4028/www.scientific.net/ssp.298.208.
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This study investigated the sintered metal among the regular finned heat sink. And a metal foam heat sink for power module cooling is designed. An improved computational model for effective thermal conductivity was obtained. Contrast to the two types of the heat sink, it is found that under the condition of the constant heat flow density, the heat accumulated is absent in metal foam heat sink. Meanwhile, the heat transfer coefficient of the metal foam heat sink is 3.6 times that of the finned heat sink of equivalent geometric parameter. At the same drop pressure, the air velocity of the metal foam heat sink is lower than that of the finned heat sink. The velocity of air in the foam radiator is lower than that in the finned radiator. Under the same fan power, the gain factor of the four finned metal foam radiators is about 20 times higher than that of the ribbed radiators of the same conditions.
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Zhang, Zhong Lin, Qian Hui Gang, Peng Qiu, Shu Han Wang i Cong Yu Bai. "A Study on Performance Test of the Self-Cooled System of High-Voltage SVC Valve Group". Applied Mechanics and Materials 713-715 (styczeń 2015): 1322–24. http://dx.doi.org/10.4028/www.scientific.net/amm.713-715.1322.
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The high-voltage SVC realizes the dynamic reactive power compensation through the real-time control over the breakover and cut-off of thyristor. Because the current passing through thyristor is large, the frequent break-make will lead to a lot of thermal loss, so it should be cooled in time. The self-cooled heat pipe cooling system is a traditional high-voltage SVC cooling system, which is expensive and heavy because it adopts relatively expensive copper product and aluminium product.This paper introduces a new heat pipe radiator. Compared to the traditional heat pipe radiators, it is light in weight, small in volume and low in cost. The performance test shows that the thermal resistance of the radiator is 0.064°C/W, that the main performance indexes are superior to those of the similar heat pipe radiators at home and abroad and that its self-cooling ability has achieved a high level. Therefore, it will greatly promote the promotion and application of this technology in China.
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Л. А., Кущев,, Мелькумов, В. Н., Саввин, Н. Ю. i Чуйко, В. В. "Simulation of Heat Carrier Motion in Tubular Heating Radiators". НАУЧНЫЙ ЖУРНАЛ СТРОИТЕЛЬСТВА И АРХИТЕКТУРЫ, nr 4(68) (21.12.2022): 40–49. http://dx.doi.org/10.36622/vstu.2022.68.4.004.
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Постановка задачи. Рассматривается движение теплоносителя в секциях трубчатых радиаторов отопления оригинальных конструкций, содержащих турбулизаторы разных типов. Необходимо разработать модели движения теплоносителя в рассматриваемых конструкциях в диапазоне скоростей 0,5-1,5 м/с и сравнить интенсивность турбулизации потока в них. Результаты. С помощью модуля Flow Simulation программного комплекса SOLIDWORKS получены результаты моделирования движения теплоносителя в секциях оригинальных трубчатых радиаторов отопления с турбулизирующими вставками. Построены 3D-модели секций радиаторов. Приведены зависимости числа Re от скорости движения теплоносителя и распределение интенсивности турбулентности в секциях радиаторов. Выводы. По результатам моделирования произведено сравнение конструкций секций оригинальных трубчатых радиаторов отопления со стандартным. Определена турбулизирующая вставка, обеспечивающая наибольшее число Re и интенсивность турбулентности в секции радиатора. Statement of the problem. The movement of the coolant in sections of tubular heating radiators of original designs containing various types of turbulators is considered. It is necessary to develop models of the movement of the coolant in the structures under consideration in the speed range of 0.5-1.5 m/s and compare the intensity of flow turbulence in them. Results. Using the Flow Simulation module of the SOLIDWORKS software package, the results of modeling the movement of a coolant in sections of original tubular heating radiators with turbulent inserts were obtained. 3D models of radiator sections were built. The dependences of the Re number on the coolant velocity and the distribution of turbulence intensity in the radiator sections are given. Conclusions. Based on the results of the simulation, the designs of the sections of the original tubular heating radiators were compared with the standard ones. A turbulent insert providing the highest Re number and turbulence intensity in the radiator section has been determined.
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Benakopoulos, Salenbien, Vanhoudt i Svendsen. "Improved Control of Radiator Heating Systems with Thermostatic Radiator Valves without Pre-Setting Function". Energies 12, nr 17 (21.08.2019): 3215. http://dx.doi.org/10.3390/en12173215.
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Low-temperature district heating will play an important role in a future free of fossil fuels. This will only be able to be realized through the low-temperature operation of heating systems in existing buildings. Existing radiator systems can operate with low temperatures for most of the year because they are designed for extremely cold days, but errors have to be corrected and the control of the radiator systems needs to be improved. In this paper, we present a strategy to achieve low-temperature operation from the radiator system of a multi-family building in Denmark without a pre-setting function in the thermostatic radiator valves. The strategy is based on operating the system with a combination of a minimum supply temperature and small temperature differences over the radiators. The operation of the system is analyzed through a thermal-hydraulic model. A minimum supply temperature weather compensation curve was calculated and implemented in the central supply temperature control. Return temperature measurements in the substation, the risers, and several critical radiators were performed before and after the implementation of the strategy. The measurements confirm that a lower supply temperature results in a reduction of the return temperature. However, the system operator needs to be supported by a tool package to correctly maintain the system’s operation.
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You, Xiaolong, Chengdong Luo, Zewei Pu, Jincheng Hu, Lidan Zhou i Gang Yao. "An Improved Design for a Heat Sink of a Power Conversion System Adapted to the High Altitude and Cold Environment of the Plateau". Journal of Physics: Conference Series 2731, nr 1 (1.03.2024): 012033. http://dx.doi.org/10.1088/1742-6596/2731/1/012033.
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Abstract Currently, there are many studies on power conversion system (PCS) in the industry, but there are few studies on high-altitude and plateau application scenarios. This paper takes the extreme environment of plateau and high altitude as the research background, uses PLECS software to establish a thermoelectric simulation of a three-phase LCL grid-connected inverter, and calculates the total heat loss of the power devices IGBT and diodes in the PCS and the power loss of the grid-connected filter. Combining the overall heat generation of IGBTs, diodes and filters and considering the characteristics of high-altitude extreme environments, two liquid-cooled radiators with different structures were designed to measure the thermal resistance and pressure loss of the two radiators (reflecting Flow resistance) and heat dissipation efficiency are quantitatively calculated. The results show that the heat dissipation performance of the liquid cooling radiator designed by the latter is better than that of the former, verifying that by improving the channel structure and size of the liquid cooling radiator, the thermal resistance and flow resistance of the radiator itself can be reduced, and its heat dissipation performance can be improved.
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Alekseytsev, S. A., A. P. Gorbachev i N. V. Tarasenko. "Modified printed two-band dipole radiators". Journal of «Almaz – Antey» Air and Space Defence Corporation, nr 3 (30.09.2017): 46–50. http://dx.doi.org/10.38013/2542-0542-2017-3-46-50.
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The study describes the modified two-band printed dipole radiators, which are implemented as integrated radiating modules containing a compact printed version of a new coaxial dovetail balancing system, and two printed dipoles implemented as corresponding continuations of a feeding strip line and an open loop. We considered some features of structural implementation and technological completion and showed the optimized geometric parameters of the printed version topology. The approach introduced is confirmed by experimental results contributing to the estimation of the maximum achievable radiator performance
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Canazas, Jose. "Field Study on the Air-Side Heat Transfer Performance of Copper Finned-Flat Tubes for Heavy-Duty Truck Radiators". International Journal of Heat and Technology 39, nr 5 (31.10.2021): 1451–59. http://dx.doi.org/10.18280/ijht.390506.
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Heavy-duty truck cooling systems have been given low importance in the enhancement and research of heat transfer performance since off-highway conditions are hard to evaluate in laboratory essays or CFD studies. The present work is performed to evaluate the heat transfer performance of copper finned-flat tubes used in heavy-duty truck radiators. Parameters were measured in the field of two heavy-duty truck engines cooling systems. In both vehicles water is used as the cooling fluid. The results showed that the Air convective heat transfer coefficient and Overall heat transfer coefficient on the air side decreases as the Reynolds Number decreases and increases as passing through the first row to the fourth row. Additionally, the mass air flow and heat transfer rate have very high values in comparison from normal automotive radiators' operative conditions, since heavy-duty truck radiators require a large heat transfer rate. The analysis presented in this paper was used for a heavy-duty truck radiator but can be extended to any equipment with finned flat tubes. A more accurate study should be done considering vibrations and different environmental conditions.
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Jurkschat, Simon, Florian Felix Sehr, Karsten Fransen, Andre Beblek i Viktor Grinewitschus. "Measurement Data-Based Estimation of the Suitability of Existing Properties for the Operation of x to Water Heat Pumps Using a Seed of 100 Multi-Family Houses and Different Power Shifting Approaches". Energies 16, nr 21 (31.10.2023): 7352. http://dx.doi.org/10.3390/en16217352.
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The German government’s ambitious goal of achieving CO2 neutrality by 2045 has prompted a focus on improving building insulation as a vital step toward energy efficiency. However, in this process, existing radiators and boilers are often left unchanged. Moreover, during the construction of buildings, heating systems are often designed with excess capacity to ensure there is no risk of insufficient heat supply during operation. This research presents various approaches to reduce the required radiator supply temperature, utilizing data from a study conducted in 100 multifamily buildings. The approaches encompass reducing the heat reserve, shifting the heat output, optimizing radiator utilization, and conducting heat demand analysis. The findings reveal that in pre-existing buildings equipped with radiators, it is possible to significantly lower supply temperatures without affecting the indoor temperature. Applied on the seed, reducing the heat reserve could reduce the median temperature by 18.5 K, thus curtailed by the most utilized radiator in the median to 7 K. Furthermore, the heat demand analysis showed that the consumption could decrease in the median by 13%, the peaks in median even by 29%. While each approach is analyzed individually, their combined implementation has the potential to considerably enhance the efficiency of water-to-water heat pumps, thanks to the reduced requirement for high supply temperatures.
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Võsa, Karl-Villem, Andrea Ferrantelli i Jarek Kurnitski. "Assessment of downward draught in high-glazing facades in cold climates – experimental and CFD study into draught control with a 21-type radiator". E3S Web of Conferences 246 (2021): 02002. http://dx.doi.org/10.1051/e3sconf/202124602002.
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This paper investigates the interaction of a radiator’s thermal plume and downdraught of cold glazed surfaces. Draughts in working areas are one of the most common thermal comfort complaints in modern buildings. A typical solution for dealing with these draughts is positioning the heat emitters such as radiators or convectors under the windows. However, with thermally efficient envelopes, the internal loads compromise a relatively high fraction of the heating demand and the emitters are working under partial loads in modern buildings. This study comprises two parts: an experimental phase in the EN442 standardized test chamber with a 21-type radiator, and a CFD simulation phase, where the model is validated and applied under an expanded set of boundary conditions. The expanded simulation set results provide preliminary insight into sizing and design. More specifically, the thermal plume can be parametrised with a velocity and temperature value along with the room air and glazing temperatures for a broader analysis and assessment of the risk of draught.
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Huang, Haibo, Xiaohua Huang, Zaijun Cheng i Yuanzhang Wang. "Simulation study of nanomaterials in heat pipe enhanced high power LED heat sink". Journal of Physics: Conference Series 2535, nr 1 (1.06.2023): 012021. http://dx.doi.org/10.1088/1742-6596/2535/1/012021.
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Abstract To facilitate the simulation of heat dissipation of high-power LED lamps, a set of simplified models for tubular heat pipes and carbon nanotube arrays were first established to estimate their thermal conductivity. Then several kinds of radiators were designed. The application of nanomaterials and heat pipes in the heat dissipation of lamps was studied by the finite element method. It is found that the radiator with vertical suspended fins strengthened by a heat pipe and heat dissipation coating has a better heat dissipation effect than other radiators. Finally, the simulation study of thermal interface materials and heat dissipation coatings for lamps and lanterns heat dissipation is carried out. The results show that the thermal interface materials of carbon nanotubes and carbon nano coatings can enhance the heat dissipation performance of lamps.
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Zurghiba, Hizanorhuda, Kumaran Kadirgama, M. M. Noor, R. A. Bakar i Semin. "Automotive Radiators: An Experimental Analysis of Hybrid Nanocoolant". E3S Web of Conferences 488 (2024): 02004. http://dx.doi.org/10.1051/e3sconf/202448802004.
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A hybrid nanocoolant is a novel type of heat transfer enhancement medium that has the potential to enhance the performance of automotive radiators by improving heat transfer efficiency and heat dissipation. The focus of the present work was to investigate the effect of different hybrid nanocoolant mixing ratios on Reynolds number, Nusselt number, Friction factor, heat transfer coefficient and convective heat transfer on heat transfer performance. Single and its hybrid nanocoolant were tested through a commercial-sized automotive radiator and a scaled-down automotive radiator to determine its laminar convective heat transfer. The nanocoolants are prepared with a fixed volume fraction of 0.01 vol% and for hybrid nanocoolants, different ratios of CNC and CuO nanoparticles are formulated. The studies utilised flow rates of 0.75, 1.00, and 1.25 LPM with a radiator inlet liquid temperature of 80°C. The experimental results show that the Reynolds number, Nusselt Number, heat transfer coefficient and convective heat transfer are proportionally related to the volumetric flow rate, while the friction factor decreases when there is an increase in the flow rate. A scale-down radiator with a low-volume concentration of hybrid nanofluids able to improve the heat transfer efficiency by 92.43% compared to conventional fluids in a commercial-sized car radiator.
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Stenqvist, Torkel, Kristoffer Bång, Sören Kahl, Arnaud Contet i Oskar Karlsson. "Ageing of Brazed Aluminium AA6xxx Alloys for Vehicle Radiators". Materials Science Forum 794-796 (czerwiec 2014): 1239–44. http://dx.doi.org/10.4028/www.scientific.net/msf.794-796.1239.
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Some aluminium alloys with Mg-Si age-hardening are used in vehicle radiators. For cost reasons they are preferably delivered in a naturally aged temper. Estimated minimum time of natural ageing between brazing and when the radiator is taken into service is 14 days. At the service temperature of 95°C, the radiator material will continue to age harden. For accelerated durability testing it is vital to use a radiator with the strength and ageing response of a service radiator. We investigated whether the full 14 days of natural ageing were needed, or if the time could be shortened. Since a vehicle is not in constant use, the radiator temperature will vary over time. We therefore compared cyclic ageing between ambient temperature and 95°C to continuous ageing at 95°C. The Sapa Heat Transfer alloys FA7870 (for headers) and FA7850 (for tubes) were subjected to different ageing times at different temperatures. Tensile and hardness were performed to assess the ageing effect. It was found that natural ageing reduced hardening during the subsequent ageing at service temperature ageing effect, an effect that was most pronounced for the first four days. There was no difference between continuous and cyclic ageing.
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Rusov, Yu S., i S. S. Krapivina. "Research of the Possibilities of Matching the Multi-element Receiving-Transmitting Irradiator Aperture". Radio Engineering, nr 1 (30.05.2021): 1–13. http://dx.doi.org/10.36027/rdeng.0121.0000168.
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Currently, aperture antennas with spatial excitation, such as reflector antennas and phased array antennas, are widely used in radar. The composition of such an antenna includes an irradiator, which can be made in the form of a small-element array of radiators to form a set of necessary radiation patterns. Monopulse irradiators are often used, which form both total and difference directional patterns. When performing an irradiator based on waveguide parts, radiators in the form of horns or open ends of waveguides are installed in its aperture. Waveguide irradiators with four and twelve horns are widely used. One of the main electrical characteristics of such an irradiator when used as part of a receiving-transmitting antenna is the isolation of the transmitting and receiving paths. Matching the aperture of the transmitting and receiving irradiator has a significant effect on the isolation of its waveguide channels. With small transverse dimensions of the radiators in the form of open ends of waveguides, it is not possible to obtain high isolation of waveguide channels without the use of additional matching elements. The task of research the effect of matching the aperture of a waveguide multi-element irradiator on the isolation of its transmitting and receiving channels, as well as the ways of matching its radiators, is set.The article considers a four-horn irradiator, the aperture of which contains radiators in the form of open ends of a square waveguide. Each radiator has the radius rounding required for the manufacture of the product using the available technological processes. To match the emitter, a dielectric plate is installed inside it. During the research the thickness of the plate and its location relative to the aperture plane changed. The characteristics of matching the radiators with a plate made of teflon, polyethylene and ST-4 material based on polymers filled with titanium dioxide are presented.The proposed method of matching the opening of a multi-element irradiator with a transverse emitter size of 0,68λ (λ is the wavelength in free space corresponding to the average frequency of the operating band) makes it possible to improve the isolation of the receiving and transmitting waveguide channels by at least 4 dB in the frequency band of up to 3%.
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Ahmed, Zakariya, i Akanksha Mishra. "Heat Transfer Enhancement of Radiators Using Various Approaches: Review". International Journal of Advance Research and Innovation 6, nr 2 (2018): 69–82. http://dx.doi.org/10.51976/ijari.621811.
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This paper reviews heat transfer enhancement of radiators using different approaches. It has been found that different method of heat transfer augmentation has been employed in different radiator design. These methods ranging from fin design modification, increasing core depth of radiator, change of tubes type, increasing surface area of radiator core, change of fin material, change of flow arrangement and changing the different types of fluid and mixture concentration. The performance of a radiator depends on its thermal and hydrodynamic performance. Certain parameters are of importance to the radiator performance such as; convective heat transfer co-efficient, pressure drop, inlet and outlet coolant temperature, air and coolant mass flow-rates, fin type, fin dimension and material. The various approaches are considered, depending on the application requirement and utilizing range. Radiator design modification such as increase in number of fins and tubes, material substitution have their limitations with certain negative consequences like added cost and weight with low efficient thermal performance compare to utilization of Nano-fluid approach. The engine life and its performance depend on coolant temperature. The application of nano-fluid in automobile radiator as coolant greatly affects the performance of the engine which in turn enhances its life span and fuel consumption. This paper attempts to review literature related to various heat transfer enhancement methods in vehicle radiator with different design, and compares the most effective approach amongst the methods taking into consideration cost, weight and thermal efficiency.