Ece Aylı - Profile on Academia.edu (original) (raw)

Papers by Ece Aylı

Hitite journal of science and engineering, 2018

R ehabilitation of hydraulic turbines of existing po- wer plants is an important topic because of... more R ehabilitation of hydraulic turbines of existing po- wer plants is an important topic because of the low performance, poor reliability, frequent maintenance intervals and undesirable cavitation properties of old turbines at the plants. Rehabilitation projects increased worldwide to improve turbine designs and to reach the desired performance characteristics, especially with the improvements in computational power and Computational Fluid Dynamics (CFD) technology. However, rehabilitation of old power plants is often more difficult than the design of the turbines for new power plants since most of the existing parts cannot be altered because some of the parts are buried and the space is limited with the size of the old turbine. Both experimental and numerical methods are common in the design [1] and rehabilitation of Francis turbines. Performing numerical simulations is an efficient approach as an alternative to model tests. Steady state and transient Francis turbine simulation results are presented in the study of Beatove et al. [2]. Interactions

International Journal of Materials, Mechanics and Manufacturing, 2013

Electronic systems cooling is an attractive research area in engineering. The aim of this researc... more Electronic systems cooling is an attractive research area in engineering. The aim of this research is to design vortex promoters for cooling of electronic equipment. Different shapes of vortex promoters are used in the experimental study for turbulent flow and the results are used to validate the results of a previous computational work performed by the authors. Another aim is to choose an appropriate promoter and promoter location which provides best turbulence effects and most effective cooling. Temperature values are measured with thermocouples at several monitoring locations. The results show that the most effective vortex promoter for cooling is triangular type of promoter for the flow conditions tested.

Experimental Investigation of Heat Transfer and Pressure Drop Over Rectangular Profile Fins Placed in a Square Channel

Proceeding of Proceedings of CONV-14: International Symposium on Convective Heat and Mass Transfer. June 8 - 13, 2014, Kusadasi, Turkey, 2014

In this study, with the help of a fan, fully developed turbulent flow conditions are experimental... more In this study, with the help of a fan, fully developed turbulent flow conditions are experimentally obtained to investigate the heat transfer and pressure drop characteristics of rectangular fins. Fins with different geometries are placed to the bottom surface of a square shaped channel. Finned test pieces are heated by constant heat flux and other parts are kept as well insulated. The effect of fin height to the heat transfer coefficient is investigated by performing experiments. Temperature distributions, heat transfer coefficient and velocity distributions for different fin height cases are examined.

and Technology was awarded a grant for a project on "Design, Construction and Test of Hydraulic T... more and Technology was awarded a grant for a project on "Design, Construction and Test of Hydraulic Turbines" from Turkish Ministry of Development. The project includes Computational Fluid Dynamics (CFD) aided hydraulic and structural design, geometry optimization, manufacturing and testing of hydraulic turbines. The main objective of the research presented here is to design a hydro turbine test stand which tests the performance and cavitation characteristics of turbine models according to standards. The paper describes the characteristics of the designed test stand.

Experimental investigation and CFD analysis of rectangular profile FINS in a square channel for forced convection regimes

International Journal of Thermal Sciences, Nov 1, 2016

Abstract Steady-state heat transfer from rectangular fin arrays is examined experimentally and nu... more Abstract Steady-state heat transfer from rectangular fin arrays is examined experimentally and numerically for turbulent fully developed flow. The effects of geometrical parameters on heat transfer coefficient and Nusselt number are investigated. For different inter fin ratios, Reynolds number and Nusselt number dependence of the results is investigated. A generalized empirical correlation for Nusselt number is developed for rectangular fins for a Reynolds number range of 17 × 107

International Journal of Flow Control, Jun 1, 2012

Studies related to supersonic cavity flow are very important for aeronautics applications. Unders... more Studies related to supersonic cavity flow are very important for aeronautics applications. Understanding the physics of cavity flows is crucial for both fluid mechanics and engineering applications. Supersonic cavity flow and control techniques for this type of flow have been studied for many decades. A review of literature on numerical and experimental cavity flow is provided and the flow mechanism inside the cavity is explained using example studies from literature. It is necessary to understand the complex nature of the flow before developing control methods for the cavity flow oscillations. The literature on the development of methods to control the flow oscillations in cavities which are harmful for aircraft is also reviewed. Feasibility of laser energy deposition as an actuator for flow control is investigated demonstrating examples from literature.

4.2 Heat Exchangers

Elsevier eBooks, 2018

This chapter aims to provide information on classification, types, design methodology, and select... more This chapter aims to provide information on classification, types, design methodology, and selection of heat exchangers (HEX), focusing on plate HEX. The details of a software developed based on correlations obtained using experimental data are presented. Plate HEX literature is explained in detail and the correlations in literature are used in the developed HEX selection software for comparison with the new correlations. The analysis shows that specific correlations based on experimental data are necessary to be used with plates utilized in HEX selection, since the plate geometries are unique and need specific correlations to reflect their properties correctly.

Advancing Fluid Mechanics Through Machine Learning: Case Studies and Computational Insights

Analysis of heat transfer enhancement of passive methods in tubes with machine learning

Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, Oct 23, 2023

Clean energy generation in residential green buildings

Due to the recent investigations, buildings consume a considerable amount of the electricity, dri... more Due to the recent investigations, buildings consume a considerable amount of the electricity, drinking water, global final energy use and as a result are responsible for one third of the global carbon emissions. Therefore, building sector has a key role to reach global energy targets. In this sight, this study draws attention to the sustainable energy performances of green buildings (GBs) and aims towards the GBs concept which includes renewable sources in the construction and lifetime utilization.

Bulletin of the American Physical Society, Nov 24, 2014

dropower is one of the clean, renewable, flexible and efficient energy resources. Most of the dev... more dropower is one of the clean, renewable, flexible and efficient energy resources. Most of the developing countries invest on this cost-effective energy source. Hydroturbines for hydroelectric power plants are tailor-made. Each turbine is designed and constructed according to the properties, namely the head and flow rate values of the specific water source. Therefore, a center (ETU Hydro-Center for Hydro Energy Research) for the design, manufacturing and performance tests of hydraulic turbines is established at TOBB University of Economics and Technology to promote research in this area. CFD aided hydraulic and structural design, geometry optimization, manufacturing and performance tests of hydraulic turbines are the areas of expertise of this center. In this paper, technical details of the design and construction of this one of a kind test facility in Turkey, is explained. All the necessary standards of IEC (International Electrotechnical Commission) are met since the test facility will act as a certificated test center for hydraulic turbines.

Supervised learning method for prediction of heat transfer characteristics of nanofluids

Journal of Mechanical Science and Technology, May 1, 2023

Performance Determination of Axial Wind Tunnel Fan with Reverse Engineering, Numerical and Experimental Methods

Journal of Computing and Information Science in Engineering, Jan 27, 2022

In today’s technology, in case of the need for rehabilitation, renovation, or damage, it is neces... more In today’s technology, in case of the need for rehabilitation, renovation, or damage, it is necessary to recover the problems quickly with a cost-effective approach. In the case of destructive failure, or misdesign of the devices, replacing the problematic part with the new design is crucial. In order to substitute the related part with the efficient one, reverse engineering (RE) methodology is utilized. In this paper, from the perspective of engineering implementation and based on the idea of reverse engineering, axial wind tunnel fan is rehabilitated using numerical and experimental methods. The current study is focused on an axial pressurization fan placed into Cankaya University Mechanical Engineering Laboratory wind tunnel that has firm guaranteed specifications of 5.55 m3/s airflow capacity. The measurements performed during experiments showed that the fan provides less than 60% airflow compared with firm guaranteed specifications. In order to determine the problems of the existing fan, a reverse engineering methodology is developed, and the noncontact data acquisition method is used to form a computer aided drawing (CAD) model. A computational fluid dynamics (CFD) methodology is developed to analyze existing geometry numerically, and results are compared with an experimental study to verify numerical methodology. According to the results, the prediction accuracy of the numerical method can attain 92.95% and 96.38% for flowrate and efficiency, respectively, at the maximum error points.

Solar Chimney Power Plant Performance for Different Seasons Under Varying Solar Irradiance and Temperature Distribution

Journal of Energy Resources Technology, 2020

One of the most promising renewable energy sources is solar energy due to low cost and low harmfu... more One of the most promising renewable energy sources is solar energy due to low cost and low harmful emissions, and from the 1980s, one of the most beneficial applications of solar energy is the utilization of solar chimney power plants (SCPP). Recently, with the advancement in computer technology, the use of computational fluid dynamics (CFD) methodology for studying SCPP has become an extensive, robust, and powerful technique. In light of the above, in this study, numerical simulations of an SCPP through three-dimensional axisymmetric modeling is performed. A numerical model is created using CFD software, and the results are verified with an experimental study from the literature. The amount of solar radiation and surrounding weather (ambient temperature) were analyzed, and the effects of the irradiance and air temperature on the output power of the SCPP were studied. Ambient temperature is considered as one of the most important factors that influence collector efficiency in a nega...

Engineering Applications of Computational Fluid Mechanics, 2016

The runner design is the most challenging part of the turbine design process. Several parameters ... more The runner design is the most challenging part of the turbine design process. Several parameters determine the performance and cavitation characteristics of the runner: the metal angle (flow beta angle), the alpha angle, the blade beta angle, the runner inlet and outlet diameters, and the blade height. All of these geometrical parameters need to be optimized to ensure that the head, flow rate and power requirements of the system are met. A hydraulic designer has to allocate time to optimize these parameters and should be experienced in carrying out the iterative design process. In this article, the turbine runner parameters that affect the performance and cavitation characteristics of designed turbines are examined in detail. Furthermore, turbines are custom designed according to the properties of hydroelectric power plants; this makes the design process even more challenging, as the rotational speed, runner geometry, system head and flow rate vary for each turbine. The effects of the design parameters are examined for four different turbine runners specifically designed and used in actual power plants in order to obtain general results and generalizations applicable to turbine design aided by computational fluid dynamics (CFD). The flow behavior, flow angles, head losses, pressure distribution, and cavitation characteristics are computed, analyzed, and compared. To assist hydraulic designers, the general influences of these parameters on the performance of turbines are summarized and empirical formulations are derived for runner performance characterization.

Computational Fluid dynamics based hill chart construction and similarity study of prototype and model francis turbines for experimental tests

Design and Construction of an Experimental Test Rig for Hydraulic Turbines

Every turbine for every hydroelectric power plant is unique; therefore its model has to be design... more Every turbine for every hydroelectric power plant is unique; therefore its model has to be designed using state of the art design techniques and tested before the actual prototype which is costly, is manufactured. In this study, the details of the design and construction of a hydroturbine test facility at TOBB University of Economics and Technology are explained. The facility will be used to test hydroturbine models up 2MWs of power simulating turbine prototypes. The performance and cavitation tests of the turbines will be performed utilizing this facility according to International Electrical Commission (IEC) standards. The test facility is 19 meters long with a base area of around 600 meter squares. The hydraulic analysis of the designed set-up is performed using a system where valves, pipes, structures, water records and connections form an intelligent system, same with the experimental facility. According to the results, system performance is checked, alternative designs are evaluated and operating strategies are defined by minimizing the losses.

CFD Analysis of 3D Flow for 1.4 MW Francis Turbine and Model Turbine Manufacturing

Hydroenergy is one of the most useful renewable energy sources. Hydropower is a vital source as i... more Hydroenergy is one of the most useful renewable energy sources. Hydropower is a vital source as it is clean, sustainable and cost effective. Francis type hydroturbines are applicable to a wide range of head and flow rate values. Spiral case, stay vane, guide vane, runner and draft tube are the basic components of a Francis turbine. In this paper, CFD based 3D numerical simulations of steady turbulent flow in a Francis turbine for an actual power plant, BUSKI HES in Turkey, is presented.

Investigation of aerodynamic and aeroacoustic behavior of bio-inspired airfoils with numerical and experimental methods

Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science

This article presents numerical and experimental studies on the aerodynamic and aeroacoustic char... more This article presents numerical and experimental studies on the aerodynamic and aeroacoustic characteristics of the NACA0012 profile with owl-inspired leading-edge serrations for aeroacoustic control. The leading-edge serrations under investigation are in a sinusoidal profile with two main design parameters of wavelength and amplitude. The noise-suppressing ability of sinusoidal serrations is a function of several parameters such as amplitude, wavelength, inflow speed, angle of attack, which are examined in this study. Amplitude (A) and wavelength (λ) of the serration are varied between 1.25 and 2.5, 20 < λ < 60, respectively. The corresponding Reynolds numbers are between 1 and 3 × 105. The angle of attack for each configuration is changed between 4° and 16°. Forty different configurations are tested. According to the results, owl-inspired leading-edge serrations can be used as aeroacoustic control add-ons in blade designs for wind turbines, aircraft, and fluid machinery. Res...

Prediction of the heat transfer performance of twisted tape inserts by using artificial neural networks

Journal of Mechanical Science and Technology