
Tuba OkutucuIstanbul Technical University · Institute of Energy
Tuba Okutucu
PhD
Looking for motivated BS, MS, and PhD students to be funded through a TUBITAK project on battery thermal management.
About
51
Publications
7,505
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
655
Citations
Introduction
Publications
Publications (51)
Copper (Cu) has been an essential ingredient in the production of silvered-glass reflectors used in the concentrated solar power (CSP) systems. However, due to added material cost and the environmental burden induced by Cu mining, researchers have started to look for ways to develop copper-free coating systems for reflectors used in solar thermal a...
This conference revealed that whether solar batteries using in PV system need a thermal management application and results show that to better efficiency for off-grid PV system,thermal management application are found to be needed.
Metal-Insulator-Metal (MIM) nanostructures provide tunable multiple absorption/emission peaks desirable for spectroscopy, light sensing and thermophotovoltaic (TPV) applications. The efficiency of TPV systems can be improved by employing MIM emitters with resonators that allow high emission above PV cell bandgap and low emission elsewhere. Although...
Photovoltaic (PV) applications require the cell to absorb photons with energies higher than its bandgap and minimize reflection for effective energy conversion. Silicon-based PV cells are usually textured with micro/nano structures to reduce their reflectivity on a broad spectrum range and to increase their light absorption. This approach increases...
Steady state operation of the heat exchanger of a Joule-Thomson cryocooler is studied numerically through a one-dimensional model. Argon is used as the working fluid. The developed model is first verified using a cooler configuration that is studied extensively in the literature. Then the model is improved in several ways. A major mistake seen in m...
Near-field radiative transfer (NFRT) refers to the energy transfer mechanism which takes place between media separated by distances comparable to or much smaller than the dominant wavelength of emission. NFRT is due to the contribution of evanescent waves and coherent nature of the energy transfer within nano-gaps, and can exceed Planck's blackbody...
Near-field radiative transfer (NFRT) between parallel-layers separated by nanometer size gaps holds great potential for applications in nano-thermophotovoltaic cells. These layers can be homogeneous surfaces or comprised of structured or porous materials. Presence of such complex structures are particularly appealing for other applications such as...
Understanding of near-field radiative transfer is crucial for many advanced applications such as nanoscale energy harvesting, nano-manufacturing, thermal imaging, and radiative cooling. Near-field radiative transfer has been shown to be dependent on the material and morphological characteristics of systems, the gap distances between structures, and...
Effects of layer thickness modifications on laser induced temperature distribution inside three material, highly reflective thin film coatings are studied with numerical simulations. As a base design, a 21 layer coating composed of HfO2, SiO2 and TiO2 layers of quarter wave thickness is considered. First, the laser induced temperature distribution...
Convection heat transfer and pressure drop characteristics of water based silver nanowire suspensions flowing through CMOS compatible monolithic microchannel heat sinks are investigated experimentally. Three different rectangular channels of 200 μm×50 μm, 100 μm×50 μm and 70 μm×50 μm cross sectional area are used during the experiments. The stabili...
Microchannel heat exchangers are used to remove the high heat fluxes generated in compact electronic devices. The roughness of the microchannels has a significant effect on the heat transfer characteristics, especially the nucleate boiling and pumping power. Therefore, development of predictive models of surface texture is of significant importance...
Heat transfer by radiation between media located a sub-wavelength distance away from each other is called near-field radiation (NFR). Nanoscale energy harvesting applications of NFR are considered to be contributing to the solution of the energy problem worldwide. SiC and GaN are considered as promising materials for the NFR harvesting applications...
This study experimentally investigates the effect of surface roughness on the hydrodynamic and thermal performance of microchannel evaporators. Three micro-evaporators of the same dimensions and different surface roughness have been fabricated by micro-WEDM. Each micro-evaporator consists of forty rectangular microchannels of 700 μm height, 250 μm...
Harvesting radiative energy with nano-scale systems has significant potential due
to the orders-of-magnitude increase in spectrally-selective radiative heat flux through nano-scale
gaps. Potential applications utilizing this enhancement include thermophotovoltaics and
nanomanufacturing. The future use of these concepts for design and development of...
Dimensionless entropy generation number in the microchannel condenser of a vapor compression refrigeration cycle is investigated. An air cooled, brazed aluminum parallel flow heat exchanger is considered as the condenser with R-134a as the refrigerant. While the effects of the fin pitch, fin height, louver angle and the air mass flow rate are inves...
The concept nanofluids have attracted attention due to the possibility of gaining increments in transport properties including thermal conductivity. While such increments have been verified to some extent, their maintenance is a concern. Since the sustainability of the properties strongly depend on the colloidal behavior, a fundamental understandin...
Silicon wafer is widely used as a base material for readout integrated circuit (ROIC) of infrared sensors. There is a heterogeneous component assembly with the silicon wafer material. Warpage behavior of silicon readout integrated circuit is dependent on the material properties and geometrical properties of the integrated materials. Warpage behavio...
A numerical model based on Cahn-Hilliard phase-field method is introduced for the first time in the literature to investigate the hydrodynamics and heat transfer characteristics of a vaporized elongated bubble in a rectangular microchannel. In the simulations, the initially nucleated bubble starts growing as it comes in contact with superheated wat...
Entropy generation in the evaporator of a microscale vapor compression refrigeration cycle is investigated under the effects of vapor quality, mass and heat flux, saturation temperature, and channel dimensions. For a variety of channel heights and mass flow rates, the optimum vapor quality, and the channel and fin widths yielding minimum entropy ge...
The arbitrary Lagrangian-Eulerian method (ALE) is used to model the hydrodynamics and the heat transfer of an elongated vaporized bubble in a microtube. The Navier-Stokes equations along with the energy equation are solved in ALE description as a single fluid with two subdomains and a moving mesh at the interface of the liquid and the vapor phases....
A numerical model based on the arbitrary Lagrangian- Eulerian method (ALE) is introduced to investigate the hydrodynamics and the heat transfer of an elongated vaporized bubble in a microchannelin detail. The Navier-Stokes equations along the energy equation are solved in ALE description as a single fluid. The finite element method is used to discr...
Improving dispersion stability of nanofluids through ultrasonication has been shown to be effective. Determining specific conditions of ultrasonication for a certain nanofluid is necessary. For this purpose, nanofluids of varying nanoparticle concentrations were prepared and studied to find out a suitable and rather mono-dispersed concentration (i....
In this study multilayer thin film optical coatings, which are indispensable parts of optical systems are investigated from a heat transfer point of view. Laser irradiation induced temperature distribution on a multilayer coating stack is obtained by discretizing the heat diffusion equation using the finite volume method. In order to obtain mathema...
This paper presents a novel hybrid piezoelectric-pyroelectric energy harvester using a cantilever beam with a PZT tip mass. The cantilever is moving between two surfaces with different temperatures under external vibration. PZT ceramic is used as the piezoelectric material, which also has pyroelectric characteristics. By using the pyroelectric effe...
Dimensional optimization of silicon microchannel heat sinks is performed by minimizing the total thermal resistance. Intel Core i7-900 Desktop Processor of chip core dimensions of 1.891 cm × 1.44 cm is considered as a reference processor which is reported to dissipate 130 W of heat. The properties are evaluated at the area weighted average of the f...
The aim of this study is to develop an interferometric technique to measure micron level clearances occurring in small piston-cylinder arrangements; such as hermetically sealed compressors. A Cartesian model of the piston cylinder arrangement is manufactured and lateral and vertical motions are generated via a step motor, and micrometers, respectiv...
A novel complementary metal oxide semiconductor (CMOS) compatible microchannel heat sink is designed and fabricated for monolithic liquid cooling of electronic circuits. The microchannels are fabricated with full metal walls between adjacent channels with a polymer top layer for easy sealing and optical visibility of the channels. The use of polyme...
The aim of this study is to develop an interferometric technique to measure micron level clearances occurring in small piston-cylinder arrangements; such as hermetically sealed compressors. A Cartesian model of the piston cylinder arrangement is manufactured and lateral and vertical motions are generated via a step motor, and micrometers, respectiv...
A nanofluid is a new class of heat transfer fluids that contain a base fluid and nanoparticles. The use of additives is a technique applied to enhance the heat transfer performance of base fluids. The thermal conductivity of the ordinary heat transfer fluids is not adequate to meet today's cooling rate requirements. Nanofluids have been shown to in...
A new method is developed for the solution of radiative transfer in a one-dimensional absorbing and isotropically scattering medium with short-pulse irradiation on one of its boundaries. The time-dependent radiative intensity is expanded in a series of Laguerre polynomials with time as the argument. Moments of the radiative transfer equation, as we...
An assessment is made of the Galerkin technique as an effective method of solution for transient radiative transfer problems in participating media. A one-dimensional absorbing and isotropically scattering plane-parallel gray medium irradiated with a short-pulse laser on one of its boundaries is considered for the application of the method. The med...
Transient analysis of the radiative transfer problem in participating media has become essential due to the recent applications involving extremely small time scales. In classical radiation problems, the time derivative term in the radiative transfer equation has a negligible order of magnitude compared to the others. Lasers of pico- to femtosecond...
With the recent advances in microfabrication, various devices having dimensions of the order of microns such as, among others, micro-heat sinks, micro-biochips, micro-reactors for modification and separation of biological cells, micro-motors, micro-valves and micro-fuel cells have been developed. These found their applications in microelectronics,...
Radiative transfer in a one-dimensional absorbing and isotropically scattering plane-parallel grey medium with a collimated short-pulse Gaussian irradiation on one of its boundaries is studied. The medium is non-emitting and the boundaries are non-reflecting and non-refracting. The Galerkin method is extended for the solution of the transient radia...