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Impact of computational radiation transfer on science, engineering and society
(Begell House Inc., 2017) Mengüç, Mustafa Pınar; Mechanical Engineering; MENGÜÇ, Mustafa Pınar
In this presentation, we will present a journey on the development of physics of radiation transfer and the related computational methodologies. We will highlight many applications of radiation transfer on fundamental sciences and engineering disciplines. This talk will not be on the details of a single computational scheme, but on the impact of a fundamental area, developed over the decades by different communities, on the society in general. We will first give a historical outline about the use of optics and radiation transfer (light and heat) over the centuries. Then, we will outline a summary of computational techniques for different physical systems used in pre-and post-digital ages, and comment on how some of these areas cross-pollinated other fields.
Open Access
Daylighting design process for visual comfort and energy efficiency for a signature building
(IOP Publishing, 2019) Kutlar, Meral Nil; Mengüç, Mustafa Pınar; Mechanical Engineering; MENGÜÇ, Mustafa Pınar
Human comfort is the most important priority in designing living environments. Achieving thermal comfort, visual comfort, effective operation of a building along with innovative energy efficiency measures require extensive involvement of engineers and architectures in tandem for the future high-performance buildings. In this paper, we focus on design of the daylighting aspects of a complicated building and present a methodology. The concept here is based on the interactions of several stakeholders including the project owner, the project architect, structural engineers, façade engineers, mechanical engineers, lighting designers and electric engineers, who are involved in extensive discussions towards the design and construction of a complicated building in a iniversity campus. Simulations are carried out using different architectural and computational techniques including DesignBuilder and Revit. The project constraints set by the stakeholder preferences are resolved with other engineering methodologies. This interactive process allowed a very favourable design of daylighting in the building. In this paper, the steps are discussed and the methodology is outlined.
Open Access
Exergy efficiency for radiation heat transfer
(IOP Publishing, 2020) Mohammed, Hayder Noori; Mengüç, Mustafa Pınar; Mechanical Engineering; MENGÜÇ, Mustafa Pınar; Mohammed, Hayder Noori
One of the evaluation criteria for the performance of thermal processes is exergy analysis. Along with energy analysis, exergy calculations provide a clear and highly effective understanding of the performance of a system. Although exergy analysis has been extensively applied to many industrial processes, there are limited works for solar energy conversion systems that include the details of radiation transfer. The use of the Carnot efficiency expressions for calculating the exergy received from the thermal radiation source is questionable because it neglects the directional and spectral aspects of radiation heat transfer. In this study, the exergy efficiency calculations for radiation heat transfer in energy conversion systems are discussed. Comparisons of different expressions for exergy efficiency are presented, and the effects of source and sink temperature variations are explored.
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Thermal analysis of perlite-reinforced concrete panels at varying moisture contents
(Begell House Inc., 2020) Çelik, S.; Mengüç, Mustafa Pınar; Mechanical Engineering; MENGÜÇ, Mustafa Pınar
Research on composite materials to be used in building insulation is presented. Building energy efficiency gained much broader significance following the COP 21 Paris agreement. In light of this outcome, this study focuses on the analysis of a construction material with improved potential building energy performance. A composite material consisting of Portland cement and perlite was developed and tested. R-values of perlite-reinforced panels at different moisture levels were measured by using the reverse heat leak method. Results obtained by this method were verified by testing materials with known properties and compared to theoretical calculations. Verification of theory was achieved within 1.8% error range. 'Thermal diffusivity values of the developed samples were also measured using the flash method. It was observed that addition of perlite to cement increases the thermal insulation capacity while thermal resistance decreases with increasing moisture content in the panels. Thermal diffusivity was found to be increasing up to a critical moisture level beyond which it decreases due to the effect of density of water that dominates the increase in thermal conductivity. These findings are considered to be significant for the construction industries, especially for regions with abundant perlite reserves.
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Computational near-field radiative transfer and nf-rt-fdtd algorithm
(Begell House Inc., 2020) Didari, A.; Mengüç, Mustafa Pınar; Mechanical Engineering; MENGÜÇ, Mustafa Pınar
Understanding the fundamentals of near-field radiative transfer is essential for future development of new sensors and energy harvesting devices. Simulations of such problems would require a coupled solution of the electromagnetic wave equations along with the expressions for thermal emission from a body at finite temperature. Versatile computational tools, which account for the intricate physics and the computational challenges of the problems, are likely to help to the future nanomanufacturing systems and processes. These simulation methodologies should be valid for one-, two-, and three-dimensional geometries with inhomogeneities and arbitrary edges and should be applicable to different materials. In this chapter, we briefly review the recent works on numerical methods used to solve the computational near-field radiative transfer (NFRT) problems. Each of these methods has its own advantages and disadvantages, and no single technique can provide the complete and robust solution for all problems at hand. Then we outline an algorithm based on the finite difference time domain (FDTD) method for one- and two-dimensional NFRT problems. For this, we discuss the details of NF-RT-FDTD algorithm and show how this approach can be applied to surfaces covered with particles as well as with thin films with inhomogeneities. We also present simulations for more complicated biomimetic structures inspired by nature for possible sensing and energy harvesting applications. © 2020 by Begell House, Inc.
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A review of optical and radiative properties of nanoparticle suspensions: effects of particle stability, agglomeration, and sedimentation
(Begell House Inc., 2020) Al-Gebory, Layth Wadhah Ismael; Mengüç, Mustafa Pınar; Mechanical Engineering; MENGÜÇ, Mustafa Pınar; Al-Gebory, Layth Wadhah Ismael
Nanoparticle suspensions (NPSs) are suspensions of nanosize particles in base fluids in the form of a solid-liquid mixture. They are used extensively in a wide range of industrial and engineering applications, and show considerably different and tunable, physiochemical, thermal, and radiative properties compared to other solutions. It has been demonstrated that added nanoparticles can significantly alter and enhance the optical and radiative properties of the base fluids. There is still a concern about the particle agglomeration and sedimentation behaviors and the long-term stability of NPSs under different conditions, which may limit their potential reliable applications. There is a close relationship between the particle agglomeration and the optical and radiative properties of nanoparticle suspensions. In this review, the relationship between these fundamental properties with the emphasis on the procedural stability of nanoparticle suspensions is explored. Different issues related to the preparation and the characterization of NPSs, their sedimentation, the effects of particle types, sizes on individual, hybrid, and agglomerated nanoparticle suspensions, as well as the effect of pH values, are discussed. Their effects on the optical and spectral radiative properties are also discussed. Simplified analyses are outlined based on dependent-independent scattering demarcation and effective properties of NPSs.
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Absorption and plasmon resonance of Bi-metallic core-shell nanoparticles on a dielectric substrate near an external tip
(Elsevier, 2020-01) Avsar, D.; Erturk, H.; Mengüç, Mustafa Pınar; Mechanical Engineering; MENGÜÇ, Mustafa Pınar
Absorption efficiency profiles and localized surface plasmon resonance (LSPR) wavelengths are reported for metallic core-shell nanoparticles (NPs) placed over a BK7 glass substrate. A numerical study is performed with the vectorized version of the discrete dipole approximation with surface interactions (DDA-Sl-v). Gold (Au) and silver (Ag) metallic components are used for the simulations of two different core-shell structures. Absorption enhancement and the hybrid modes of plasmon resonances of the core-shell structures are compared by using a measure that defines a size configuration. It is observed that a small volume fraction of the core sizes results in shell domination over the plasmon response. An additional study is conducted to discern the sensitivity of the refractive index of nanoparticles in different surrounding environments. With a selected core-shell size configuration of Ag-Au pairs, a significant absorption enhancement with a redshift of LSPR wavelength is observed for both Ag core-Au shell and Au core-Ag shell NPs. The absorption behavior of the bare metallic NPs and selected core-shell pairs in proximity to an external probe's tip is also analyzed. The gallium phosphide (GaP) and silicon (Si) tip usage are investigated with transverse electric (TE) and transverse magnetic (TM) wave polarizations. It is observed that the dominance of light polarization on the absorption enhancement of the NPs switches at different wavelengths, where the dielectric transition for tip materials occurs. These findings show the possible targeted uses of metallic core-shell nanoparticles in several areas such as nanomanufacturing, localized heating, bio-sensing, and material detection applications.
Open Access
Cascaded thermodynamic and environmental analyses of energy generation modalities of a high-performance building based on real-time measurements
(MDPI AG, 2020-04) Al Doury, Raaid Rashad Jassem; Ozkan, S.; Mengüç, Mustafa Pınar; Mechanical Engineering; MENGÜÇ, Mustafa Pınar; Al Doury, Raaid Rashad Jassem
This study presents cascaded thermodynamic and environmental analyses of a high-performance academic building. Five different energy efficiency measures and operation scenarios are evaluated based on the actual measurements starting from the initial design concept. The study is to emphasize that by performing dynamical energy, exergy, exergoeconomic, and environmental analyses with increasing complexity, a better picture of building performance indicators can be obtained for both the building owners and users, helping them to decide on different investment strategies. As the first improvement, the original design is modified by the addition of a ground-air heat exchanger for pre-conditioning the incoming air to heat the ground floors. The installation of roof-top PV panels to use solar energy is considered as the third case, and the use of a trigeneration system as an energy source instead of traditional boiler systems is considered as the fourth case. The last case is the integration of all these three alternative energy modalities for the building. It is determined that the use of a trigeneration system provides a better outcome than the other scenarios for decreased energy demand, for cost reduction, and for the improved exergy efficiency and sustainability index values relative to the original baseline design scenario. Yet, an integrated approach combining all these energy generation modalities provide the best return of investment.
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Spectrally selective filter design for passive radiative cooling
(The Optical Society, 2020-04-01) Kecebas, M. A.; Mengüç, Mustafa Pınar; Kosar, A.; Sendur, K.; Mechanical Engineering; MENGÜÇ, Mustafa Pınar
Radiative cooling is potentially one of the most innovative approaches to reducing energy density in buildings and industry, as well as achieving higher levels of energy efficiency. Several studies have reported the design of spectrally selective layered structures for daytime passive radiative cooling. However, a comprehensive design of such systems requires the spectral behavior of different materials and radiative heat transfer mechanisms to be addressed together. Here, we introduce a design methodology for daytime passive radiative cooling with thin film filters which accounts for the spectral tailoring at the visible and infrared spectrum. The major difference of this method is that it does not require a predefined target ideal emittance. The results show that higher cooling powers are possible compared to the previously reported thin-film structures, which were designed from a purely spectral perspective. The underlying mechanisms of the resulting spectral profiles, which give rise to improved performance, are investigated by wave impedance analysis. Cooling powers up to 100 W/m(2) are obtained with seven layers on Ag. The findings of this study indicate that structures with better performance in terms of cooling powers and temperature reduction rates can be obtained following the procedure discussed.
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Spectrally selective filter design for passive radiative cooling
(The Optical Society, 2020-04-01) Kecebas, M. A.; Mengüç, Mustafa Pınar; Kosar, A.; Sendur, K.; Mechanical Engineering; MENGÜÇ, Mustafa Pınar
Radiative cooling is potentially one of the most innovative approaches to reducing energy density in buildings and industry, as well as achieving higher levels of energy efficiency. Several studies have reported the design of spectrally selective layered structures for daytime passive radiative cooling. However, a comprehensive design of such systems requires the spectral behavior of different materials and radiative heat transfer mechanisms to be addressed together. Here, we introduce a design methodology for daytime passive radiative cooling with thin film filters which accounts for the spectral tailoring at the visible and infrared spectrum. The major difference of this method is that it does not require a predefined target ideal emittance. The results show that higher cooling powers are possible compared to the previously reported thin-film structures, which were designed from a purely spectral perspective. The underlying mechanisms of the resulting spectral profiles, which give rise to improved performance, are investigated by wave impedance analysis. Cooling powers up to 100 W/m(2) are obtained with seven layers on Ag. The findings of this study indicate that structures with better performance in terms of cooling powers and temperature reduction rates can be obtained following the procedure discussed.
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An adaptive vent system for localized and customized thermal management in buildings
(ASME, 2020-05-01) Keskin, Cem; Mengüç, Mustafa Pınar; Mechanical Engineering; MENGÜÇ, Mustafa Pınar; Keskin, Cem
This paper introduces an innovative ventilation system that is capable of providing localized and customized thermal conditions in buildings. The system has diffusers with individually operable flaps that facilitate asymmetric air inlet to control air flow inside a room in an effective way. Moreover, the system involves distributed temperature sensors, a user interface, and a control unit that allows creation and management of "thermal subzones" within a room in accordance with the different preferences of occupants. As a specific case, the thermal management of a typical office in an academic building is considered. Both experimental and numerical studies were conducted to show that it is possible to achieve several degrees of temperature differences at different room locations in a transient and controllable fashion. The dynamic management of the temperature distribution in a room can prevent the waste of conditioning energy. It is shown that the system provides a practical and impactful solution by adapting to different user preferences (UPs) and by minimizing the resource use. In order to deal with the complexity of design, development, and operation of the system, it is considered as a cyber-physical-social system (CPSS). The core of the CPSS approach used here is an enhanced hybrid system modeling methodology that couples human dimension with formal hybrid dynamical modeling. Based on a coherent conceptual framing, the approach can combine the three core aspects, like cyber infrastructure, physical dynamics, and social/human interactions of modern building energy systems to accommodate the environmental challenges. Besides physics-based achievements (managing temperature distribution inside a room), the new AVS can also leverage user engagement and behavior change for energy efficiency in buildings by facilitating a new practice for occupants' interaction with heating, ventilation, and air conditioning (HVAC) system.
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Coupled heat transfer analysis and experiments to evaluate the radiative cooling potential of concrete and green roofs for buildings
(Springer Nature, 2020-08) Family, Roxana; Çelik, S.; Mengüç, Mustafa Pınar; Mechanical Engineering; MENGÜÇ, Mustafa Pınar; Family, Roxana
Improving building energy efficiency is one of the most important challenges towards the mitigation of climate change concerns. Buildings use significant amount of energy for cooling loads. Development of new night-time and day-time radiative cooling modalities by roofs is essential for reducing the energy consumption during the summer months. If a surface is desired to be kept cool while exposed to the sun, it should have (i) the maximum reflection of solar energy at visible wavelength range, and (ii) the maximum radiative emission from the surface at atmospheric radiation bands (8-13 mu m wavelength range). In this study, reinforced concrete panels and three different types of plant-covered roof layers were investigated for their potential use for passive cooling applications, including moss, cactus and green leaves. Fourier transform infrared spectroscopy (FTIR) measurements were conducted to determine the absorbance of different samples at infrared wavelengths. In addition, reverse heat leak method was used to determine the effective conductivity values (R-values). The power of cooling parameter of each sample was determined first, and after that a coupled radiation and conduction heat transfer analysis was carried out to evaluate their insulation potential. It was demonstrated that moss is a better candidate to be used as a radiative cooling material, and it is a better insulator than the other tested materials.
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Deagglomeration of nanoparticle clusters in a “cavitation on chip” device
(American Institute of Physics Inc., 2020-11-01) Gevari, M. T.; Niazi, S.; Karimzadehkhouei, M.; Sendur, K.; Mengüç, Mustafa Pınar; Ghorbani, M.; Kosar, A.; Mechanical Engineering; MENGÜÇ, Mustafa Pınar
Due to the potential of significant energy release in cavitating flows, early cavitation inception and intensification of cavitating flows are of great importance. To use this potential, we investigated the deagglomeration of nanoparticle clusters with the implementation of hydrodynamic cavitation in a microfluidic device. For this purpose, a microfluidic device with a micro-orifice geometry was designed and fabricated using standard microfabrication processes. The system was tested with distilled water in the assembled experimental setup. The flow patterns were characterized using the cavitation number and inlet pressure. Titania nanoparticles were utilized to prepare nanoparticle suspensions. The suspensions were heated to allow agglomeration of nanoparticles. The system was operated with the new working fluid (nanoparticle clusters) at different inlet pressures. After characterizing flow patterns, the flow patterns were compared with those of pure water. The deagglomeration effects of hydrodynamic cavitation on nanoparticle clusters showed the possibility to apply this method for the stabilization of nanoparticles, which paves way to the implementation of nanoparticle suspensions to thermal fluid systems for increased energy efficiency as well as to drug delivery. Our results also indicate that the presence of nanoparticles in the working fluid enhanced cavitation intensity due to the increase in the number of heterogeneous nucleation sites.
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Center for Energy, Environment and Economy From Nano to Giga - Research and Applications
(Özyeğin University, 2021-08) Mengüç, Mustafa Pınar; Saygı, Dilek; Ötkün, G. E.
N/A
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The Ninth International Symposium on Radiative Transfer (RAD-19)
(Elsevier, 2021-09) Lemonnier, D.; Webb, B. W.; Mengüç, Mustafa Pınar; Mechanical Engineering; MENGÜÇ, Mustafa Pınar
N/A
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Design methodology of a concentrating solar volumetric receiver
(ASME, 2023) Akba, Tufan; Baker, D.; Mengüç, Mustafa Pınar; Mechanical Engineering; MENGÜÇ, Mustafa Pınar; Akba, Tufan
A volumetric receiver design process is proposed to respond wide range of power, outlet temperature, or mass flow rate needs. In the receiver model, concentrated solar radiation hits the inner surface cavity and heats the gaseous fluid passing through the porous media assembled between the cavity and the insulator. Porous media properties and receiver geometry are coupled in the design process to determine the best possible option. A two-step process starts with a parameter sweep to create a surrogate model. Then, gradient-based design optimization is performed using two different surrogate models to maximize the outlet air temperature for bounded design variables in receiver volume and outer surface temperature constraints. The proposed design process has the advantage of exploring more design options faster using the surrogate model and more accurate results using the base model in the plant-level simulations. The methodology is discussed by comparing the surrogate models and the model validation shows that over 95% accuracy is obtained using both surrogate models. Surrogate-based design optimization is compared as in solution time and the final results are compared with respect to the base receiver model.
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Airflow characteristics and thermal comfort of air diffusers
(ASME, 2023) Eraslan, Tolga Arda; Keskin, Cem; Mengüç, Mustafa Pınar; Mechanical Engineering; MENGÜÇ, Mustafa Pınar; Eraslan, Tolga Arda; Keskin, Cem
Indoor environment quality control is very important for building operations as occupant of buildings spend up to 90% of their time indoors. After Covid-19 pandemic break out, indoor environment quality has become even more crucial to the society because of health concerns. Indoor Environmental Quality (IEQ) covers conditions such as air quality, lighting, thermal conditions, ergonomics inside a building and their effects on the occupant or occupants of the building. Thermal conditions and air quality are usually achieved with the mechanical or natural ventilation systems or by HVAC equipment. As buildings became more complex structures, different airflow distribution systems to be developed to fulfill such requirements. For this purpose, not only the airflow distribution systems need to be modified but also diffusers that provide which supplies/draws air to/from systems are to be improved. Detailed analysis of these subcomponents is needed to assure that such devices provide high levels of comfort effectiveness and energy efficiency. The objective of this study is to develop a comprehensive analysis for air characterization and indoor air regime of different diffusers (square diffuser, operable flap diffuser) and their effect on comfort level of occupants Fanger’s model of thermal comfort is used with CFD simulations and a tool is considered for the validation experiments. Using more than 16 thermal sensors including one on a mannequin head, on a table and at foot level, the readings were correlated by using anemometers to measure air flow at supply diffuser and at different operating levels. CFD simulations were according to different scenarios which are to provide a comparison between diffusers and understand indoor airflow regimes. The results considering the flow interaction between diffusers and surroundings showed a detailed visual illustration in CFD simulations and their relation to perceived comfort levels.
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A transdisciplinary approach and design-thinking methodology for energy transition
(ASME, 2023) Özsoy, Mevhibe Canan; Mengüç, Mustafa Pınar; Mechanical Engineering; MENGÜÇ, Mustafa Pınar; Özsoy, Mevhibe Canan
The World is facing a climate crisis today. Since it is primarily due to the emissions from the use of fossil fuels, we must re-think and re-act on how we generate, transmit, distribute, and consume energy in industry, buildings, and transportation. Development of creative solutions and strategies to decrease emissions requires an energy transition framework and should involve every person, company, entity, and all governments. Such a framework can only be achieved with efforts at both local and global scales, which needs to convince (a) industries to change their traditional operation modalities, (b) people to alter their consumption behaviors, and (c) governments to change their rules, regulations, and incentives. The complexity and the magnitude of this enormous task demand coordination and collaboration of all stakeholders, besides the need for technological innovations. In this paper, we outline a transdisciplinary approach and design-thinking methodology (TADTM) to tackle this challenging task. Our premise is that such complex problems need a fundamental understanding of not only engineering solutions but also those for business operations, financing, socio-economic governance, legislation, and regulations. Also, these problems need to be considered by different decision-makers with seamless interactions and structured teamwork. Towards this, we emphasize the need for a solid transdisciplinary framework for industrial corporations to change their energy policies with the help of either/both practical and doable energy efficiency measures and using renewable/alternative energy in their operations.
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Investigation of soot formation of ethylene/air jet diffusion flame with rank correlated slw including ethylene and acetylene radiation
(Begell House Inc., 2023) Halvaşi, Berkay; Başol, Altuğ Melik; Mengüç, Mustafa Pınar; Ertunç, Özgür; Mechanical Engineering; BAŞOL, Altuğ Melik; MENGÜÇ, Mustafa Pınar; ERTUNÇ, Özgür; Halvaşi, Berkay
Radiation is significant, especially in sooting flames. The interaction between radiation and soot considerably affects the combustion regime. Spectral radiation models that account for the radiative effects of sooting flames are critical. This study numerically investigates the interaction between the radiation and soot formation on a sooting jet diffusion flame. A rank correlated spectral line-based weighted sum of gray gases (RC-SLW) global model is implemented in Ansys Fluent and used for the combustion modeling of a jet diffusion flame. RC-SLW model, including ethylene and acetylene radiation, shows considerable improvement in predicting soot volume fraction compared to the domain-based with single gray gas weighted sum of gray gases (WSGG) model in Ansys Fluent. Increasing the number of gray gases in the RC-SLW model from 5 to 22 reduces the error in the maximum soot volume fraction from 30% to 1%. It was found that the effect of ethylene and acetylene radiation in the RC-SLW model has a minor effect on soot formation. Simulations without the effect of ethylene and acetylene radiation in the RC-SLW model underpredict maximum soot volume fraction by 5%.
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Light, plasmonics and particles
(Elsevier, 2023) Mechanical Engineering; Mengüç, Mustafa Pınar; Francoeur, M.; MENGÜÇ, Mustafa Pınar
Light, Plasmonics and Particles focuses on the fundamental science and engineering applications of light scattering by particles, aerosols and hydrosols, and of localized plasmonics. The book is intended to be a self-contained and coherent resource volume for graduate students and professionals in the disciplines of materials science, engineering and related disciplines of physics and chemistry. In addition to chapters related to fundamental concepts, it includes detailed discussion of different numerical models, experimental systems and applications. In order to develop new devices, processes and applications, we need to advance our understanding of light-matter interactions. For this purpose, we need to have a firm grasp of electromagnetic wave phenomena, and absorption and scattering of waves by different size and shape geometrical objects. In addition, understanding of tunneling of waves based on electron and lattice vibrations and coupling with the thermal fluctuations to enhance near-field energy transfer mechanisms are required for the development of future energy harvesting devices and sensors.

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