Papers by Muharrem Hilmi Aksoy
In this study, numerical analyses were performed to investigate the surface roughness effect on h... more In this study, numerical analyses were performed to investigate the surface roughness effect on hydraulic efficiency of a single stage centrifugal pump with horizontal shaft. Design parameters of the pump belonging to Sempa Company were volume flow rate ( ̇) 100 m 3 /h, head (Hm) 180 kPa and impeller rotation ( ̇) 1480 rpm. During the numerical analyses, k-ε turbulence model and standard wall function were used. Leakage flows and balance holes were included in flow volume of the pump. Roughness values used in analyses are 0, 0.1, 0.3, 0.5 and 0.7 mm for wetted surface of the impeller and volute of the pump. Numerical analyses were realized at design point by using Computational Fluid Dynamics (CFD) software ANSYS-FLUENT. Boundary conditions were taken as volumetric flow rate at inlet, head at outlet, rotational motion at impeller flow volume and the surfaces contacting with the impeller solid structures. According to the numerical analyses results, as the surface roughness increases, the head and hydraulic efficiency decrease while increasing shaft power. On design flow rate the manometric head for 0 and 0.7 mm surface roughness were respectively calculated as 212,4 kPa and 172,1 kPa. Hydraulic efficiency and shaft power values for 0 mm and 0.7 mm surface roughness values were respectively found to be 68.74% -45.49 % and 8.41 kW-10.31 kW. The obtained results show that as the roughness value increases from 0 to 0.7, head of the pump is decreasing by 18.97 %, hydraulic efficiency is decreasing by 33.82 % and shaft power is increasing by 22.59% with respect to the smooth pipe wetted surface. It is suggested that the manufacturing process should be planned as much as possible less roughness wet surfaces of the pump to save energy during operating life-cyle period such as ten years.
The aim of this study is to improve the hydraulic efficiency of a multi-stage centrifugal pump by... more The aim of this study is to improve the hydraulic efficiency of a multi-stage centrifugal pump by redesigning an impeller of the pump. First, the pump impeller was redesigned according to the catalog design values of the pump. Design parameters of the pump were volume flow rate ̇= 80 m 3 /h, head per stage hm= 40 m, shaft rotation ̇= 2975 rpm. After the redesign, solid model of the impeller geometry and the flow volume of the impeller were drawn and created using Solidworks and Ansys-Fluent software. Later, an optimum grid number and size in the flow field of the impeller were generated to obtain grid independency. Numerical analyses were performed for both the original and designed impellers for different volume flow rates using Computational Fluid Dynamics (CFD) of Ansys-Fluent software. According to the CFD analyses, the performance of the redesigned impeller at the design point yield that head and hydraulic efficiency values were 52.69 m and 87.3%, respectively while those were 51.44 m and 82.3% for the original impeller. It is obtained from the impeller redesign that hydraulic efficiency and head of the impeller increase about 6% and 2.5%, respectively.
The population in the world has been tripled in the 20th century while the usage of water resourc... more The population in the world has been tripled in the 20th century while the usage of water resources has grown six-fold. Both of them will continue to increase because of industrialization, urbanization, nature of the human life and side effects of global warming. Water needs for different crops in most agricultural regions can not meet naturally by rainfall and therefore extra irrigation is needed. The irrigation cost for farmers may require large amount expenditure especially the regions away from electric utility grid. In this study, performance characteristics of water pumping system powered by both solar energy via photovoltaic panels and wind energy in a region of Konya province in Turkey are examined by using locally measured two-year period wind data at 10m mast height and long-term hourly mean solar radiation data. Solar radiation and wind speed values during summer months occur in greater amounts as the irrigation needs of the crops are the higher amount in the considered region. The reason of the considering combined solar-wind system is to support each other when one of them produces energy insufficiently. The proposed hybrid system can generate 4080kWh/year electricity and can pump 18.000m3/year water from a well with a depth of 45 m to a reservoir 5 m above ground level. With the simulated hybrid system daily-mean pumped water amounts for May, June, July and August are found to be 58,3 m³/day, 64,9 m³/day, 81,3 m³/day and 63,9 m³/day, respectively. Pumped water is considered for different crops and total field areas for melon, corn, sugar beet and potato are found as 42,6 da, 24,8 da, 18,6 da and 23,8 da, respectively by using drip irrigation method. In addition, solar-wind based systems provide advantages of having environment-friendly, low maintenance and no fuel cost while its cost is fairly high.
It is necessary to better understand and examine the complex flow patterns in the pump impeller t... more It is necessary to better understand and examine the complex flow patterns in the pump impeller to overcome problems that reduce pump efficiency and to make new designs. For this reason, the flow structure between the two blades in pump impeller, in a specially designed and installed test set in this thesis study, was experimentally determined by the Particle Image Velocity (PIV) measurement method in the middle of the impeller exit width. In the study, a 3-stage centrifugal pump with design parameters of 2850 rpm, 12.5 m³/ h flow rate and 40 m pressure head was also tested at 1900 rpm, in addition to design parameters. Experiments have been carried out at three different flow ratios for the design values of 0.85Qd-1.0Qd and 1.15 Qd for each rpm value. Numerical studies have been carried out under the same boundary conditions, and the flow structure obtained by Computational Fluid Dynamics (CFD) was compared with experimental PIV results. Experimental and numerical studies have been carried out using 3 different pump impellers, original pump impeller 6 blades (impeller 1), 4 main 4 splitter blades (impeller 2), 4 main blades without splitter blades (impeller 3).In the PIV studies, a 500 phase averaged photos was taken at the same impeller position and the flow properties were investigated with the absolute velocity vector, the relative velocity vector, the absolute velocity contour, the relative velocity contour, and the Turbulence Kinetic Energy (TKE) values. In addition, 5 different impeller-diffusers positions have been investigated in order to investigate the flow structure in the impeller and its' interaction between impeller and diffuser. The relative difference between the PIV-CFD results obtained with the 16 different points created in the pump impeller was found to be between 5.7-21.2%. In the experimental and HAD studies performed at 12.5 m³/h, the highest pump overall efficiency was 56.0% and 56.6%, respectively for the impeller 1, while the highest pump height was 46.0 m and 44.2 m for the impeller 2. In the pump used the impeller 3, the pump head remained at 37.8 m even though the pump efficiency was 55.8%. With the use of impeller 2 in the experimental studies, the head increased from 40.3 m to 44.2 m with 9.7% while overall efficiency decreased only from 56.0% to 53.7% by 4.7% compared to impeller 1.In addition, the difference between the pump characteristic values obtained in HAD and experimental studies is found to be between 1-9%. It has been observed that the absolute velocity values are in accordance with the PIV and HAD results in the impeller 2, which has a particularly lower number of blades and is more suitable for PIV measurements.
X International Conference Industrial Engineering and Environmental Protection 2020 (IIZS 2020), 2020
In this study, the temperature distributions on the cooking surfaces and the mechanical stresses ... more In this study, the temperature distributions on the cooking surfaces and the mechanical stresses caused by the pressure arising during cooking proses of the wafer baking molds made of different materials to be used in wafer baking ovens were numerically investigated. Four different materials, GGG-40, GGG-45, GG-25, GJV-350, were examined. Since the structural integrity must be demonstrated in all loading situations encountered by the molds, simulations have been done using the finite element method. It is seen that metal types have little effect on the heating time of the molds. In the thermal expansion analysis, it was seen that the material made of structural steel next to the molds was incompatible with the main material.
Türk Doğa ve Fen Dergisi , 2023
In this study, the effective solar irradiation on the PV surface, electricity generation, and per... more In this study, the effective solar irradiation on the PV surface, electricity generation, and performance ratios were investigated for a 100 kW small-scale on-grid PV system in Konya, Turkey. Five different azimuth angles-30°,-15°, 0°, 15°, and 30° were investigated for noshading simulations with a fixed optimum tilt angle of 33°. As a result, the highest effective solar radiation is obtained at an azimuth of 0° as 1966.4 kWh/m², which is 2.12%, 0.46%, 0.79%, and 2.66% greater than the other azimuth angles of-30°,-15°, 15°, and 30°, respectively. On the other hand, it is seen that the highest energy production is obtained from the system with an azimuth angle of 0° with annual energy of 174.33 MWh. This value is 1.91%, 0.37%, 0.89%, and 2.8% greater than the other azimuth angles of-30°,-15°, 15°, and 30°, respectively. In addition, to evaluate the shading effect on the performance of the PV panels, two different panel spacings as, 4 m and 8 m, were also considered. It was seen that the electricity generation with an 8 m span system was 8.88% better than the 4 m. Another finding is that the height of the panels is negligible according to electricity generation. Finally, the highest performance ratio is obtained from the azimuth angle of 0°, as 0.857.
MANAS Journal of Engineering , 2023
The installation of photovoltaic (PV) panels on building roofs has seen a significant increase in... more The installation of photovoltaic (PV) panels on building roofs has seen a significant increase in recent years due to the rising cost of conventional energy sources. This shift towards renewable energy sources has been driven by the urgent need to mitigate the effects of climate change. PV applications is one of the most sustainable and cleanest sources of renewable energy, producing no greenhouse gas emissions during operation. By reducing reliance on fossil fuels, the use of PV panels can help to reduce carbon emissions and lower the overall carbon footprint of buildings. In addition to the environmental benefits, the installation of PV panels can also provide economic benefits, such as reduced energy costs and increased property value. In the past, installations were mostly made in the direction of the south, but now the roofs of the buildings facing west, east, and even north are also considered for PV panel installations. In this study, a grid-connected PV system with an installed power of 148 kWp at the Konya Technical University (KTUN) campus is modeled by PVsyst software. The PV systems' performance on building roofs oriented in different geographical directions (north, south, east, and west) with a 30° fixed tilt angle was investigated. In the modeling, the solar irradiation coming to the surfaces of the PV panels, electricity production values, performance ratios, and their economic feasibility were calculated. The highest effective irradiation value on the panel surface was obtained from the system facing south, found as 1964.4 kWh/m². It is 20.77%, 22.87%, and 73.48% higher than the solar irradiation obtained at-90°, +90°, and 180° azimuth angles, respectively. It is concluded that the electricity generation amounts of PV systems highly depend on the azimuth angle. Similarly, the highest annual electricity production was obtained from the system installed in the 0° azimuth angle found as 254.77 MWh. The annual total electricity generation is 19.66%, 22.55%, and 69.41% higher in systems modeled toward the east, west, and north, respectively. Performance ratio, defined as the ratio of radiation coming to the panel surface and the electricity produced, has relative values between 0.843 and 0.862 for four different azimuth angles. Furthermore, as an economic analysis, the Basic Payback Period (BPP) of the projects was found as 6.92 years, 4.08 years, 4.88 years, and 5.00 years for the systems modeled in the north, south, east, and west directions, respectively. It can be concluded that the most suitable orientation is south, and the other two directions, east, and west, can also be considered feasible.
International Scientific And Professional Conference Politehnika 2023, 2023
This study investigates the viability of solar photovoltaic (PV) water pumping systems in three T... more This study investigates the viability of solar photovoltaic (PV) water pumping systems in three Turkish cities, Antalya, Aydın, and Samsun, focusing on their efficacy in agricultural irrigation. The research uses PVsyst software to examine the interplay between solar irradiation, water demand, and pump efficiency. Results reveal varying effectiveness among the provinces due to disparities in solar irradiation. Antalya and Aydın meet 97.69% and 96.43% of their annual water needs, respectively, while Samsun achieves only 73.99%, emphasizing the critical role of irradiation intensity. Evaluation of unused energy demonstrates surplus of 263 kWh for Antalya, 39 kWh for Aydın, and optimal energy utilization for Samsun. The Performance Ratio (PR) analysis underscores higher efficiency for Samsun due to its lower irradiation levels. These findings contribute valuable insights for regional solar energy applications, emphasizing the significance of location-specific strategies in advancing renewable energy technologies.
International Journal of Energy Applications and Technologies, 2023
In this investigation, the absence of an electricity grid in numerous locations, including milita... more In this investigation, the absence of an electricity grid in numerous locations, including military bases, tiny houses, and chalets, prompted the development of a model for providing electrical energy through an off-grid Photovoltaic (PV) system in Konya, Türkiye. The study delineates the daily energy consumption of a residential dwelling as 39,974 Wh/day, and the feasibility of satisfying this demand through the implementation of a 9.45 kWp PV system is scrutinized. The research encompasses the determination of optimal tilt and azimuth angles set at 35° and 0°, respectively. The maximum global effective irradiation intensity, recorded in August at 208.3 kWh/m², contrasts with the minimum intensity observed in December, registering at 106.2 kWh/m². Likewise, electricity production attained its zenith in August at 1,581.3 kWh, starkly contrasting its lowest level in December at 791 kWh. Modelling outcomes conclude that Solar Fraction (SF) values equate to unity during summer but fall below unity during winter. Furthermore, a surplus in electricity generation relative to demand is observed during the summer, resulting in the full charge of batteries. Evaluating the annual average SF, it is deduced that the modelled system fulfils 90.8% of the energy requirement. The Performance Ratio (PR), an additional pivotal parameter in PV systems, reaches its zenith at 0.865 in November and its nadir at 0.614 in August. This comprehensive study underscores the efficacy of the modelled off-grid PV system in meeting the energy demands of the selected residence, emphasizing the significance of seasonal variations and key performance metrics in assessing system performance.
International Conference on Organization and Technology of Maintenance, 2024
Improper lubrication is a leading cause of bearing failures, accounting for half of all instances... more Improper lubrication is a leading cause of bearing failures, accounting for half of all instances. Lubricating bearings with grease or oil forms a protective film that prevents direct metal-to-metal contact, reducing friction and overheating, and prolonging the bearing's lifespan. Lubrication also acts as a barrier against foreign particles and wear. In this study, an analysis of automatic lubrication in a milling plant was carried out and compared to manuel lubrication. A milling factory with 22 roller mills with a total production capacity of 450 tons/day is considered. It is calculated that the failure of eight bearings in each mill roller due to lubrication issues results in a substantial cost of $39,000 over a two-year period. The Automatic lubrication system named "SmartLub" regulates lubricant quantity, timing, and application points, ensuring optimal lubrication. The choice of the oil pump was determined by considering both the viscosity of the oil and the head loss within the piping system utilized. By adhering to calculated frequencies, the system extends bearing service life to four years. Furthermore, the manual system reduces labor costs by $400 per roller mill every two years, while unplanned downtimes caused by lubrication issues are minimized. The automatic system eliminates the need for bimonthly one-day shutdowns in the conventional lubrication systems, saving a total of six days per year. With an estimated lifespan of 20 years, the system achieved a payback period of 1.23 years, demonstrating its cost-effectiveness and long-term benefits. Overall, automation in bearing lubrication enhances machine efficiency, reduces spare parts and maintenance costs, and ensures optimal lubrication in the grain milling sector. Its implementation leads to extended bearing lifespan, reduced downtime, and improved profitability.
ACTA TECHNICA CORVINIENSIS – Bulletin of Engineering, 2024
Aerocyclone separators are crucial in separating solid particles from gas streams. These cyclones... more Aerocyclone separators are crucial in separating solid particles from gas streams. These cyclones exhibit diverse geometrical configurations in their inlet zones, including tangential, spiral, helical, and axial designs, with variations within the tangential type. Beyond their economic appeal, these devices are characterized by their resilience to high temperatures and pressures, ease of manufacturing, and uncomplicated geometrical structures. Among the factors influencing cyclone performance, the critical parameters of interest encompass dust collection efficiency and pressure loss. The present study employed a Stairmand-type counter-flow cyclone to separate flour particles dispersed within an air medium. A numerical investigation considered cyclone heights of H = 750 mm, H = 1000 mm, and H = 1500 mm. Furthermore, cyclone inlet velocities of 8 m/s, 13 m/s, and 17 m/s were specifically chosen for examination. Particle sizes ranged from 1 to 10 micrometers, ensuring the evaluation extended to conditions achieving 100% collection efficiency. A comprehensive analysis of pressure drop ratios was presented herein, offering insights into the impact of varying inlet speeds and cyclone dimensions.
International Journal of Environmental Science and Technology, 2024
This study proposed a model for estimating monthly solar radiation values using the adaptive netw... more This study proposed a model for estimating monthly solar radiation values using the adaptive network-based fuzzy inference systems (ANFIS-SR). The ANFIS-SR model is obtained by training the meteorological measurement data from the Adana province from 2017 to 2021. The monthly average sunshine duration and ambient temperature are inputs for the ANFIS-SR. The investigation evaluates the impact of different membership functions and data selection methodologies for training and testing on the ANFIS-SR outcomes. Four types of membership functions, Triangular (Trim), Gaussian, Trapezoidal, and Generalized Bell-Shaped (Gbell), are considered to study the input's influence. Additionally, two data selection cases are examined: one involving a serial date (S cases) arrangement and the other with a random (R cases) order. According to the errors, Gbell ensures higher estimating performance with the lowest error than other membership functions in training and testing data in S cases. In the case of R, Gbell is more successful in the training, while Trim can provide better estimates on the testing data. The test results show that the mean absolute percentage error and regression values are 4.364% and 0.984 for S cases and 4.265% and 0.981 for R cases, respectively. According to the obtained results, the Gbell membership function provides more solar radiation prediction performance than the others for the examined location. It also shows that random data selection outperforms serial data selection. The results prove that the proposed model ANFIS-SR can effectively model solar radiation estimation within an acceptable error range, thus offering substantial application potential in this field.
2st International EUROSA Conference, 2024
Most of the major cities in the world are coastal cities. This is a natural outcome of the needs ... more Most of the major cities in the world are coastal cities. This is a natural outcome of the needs of human civilization. Some of the mentioned needs are transporting goods (shipping in literal means) and resources such as fish. On the other hand, wind and solar energy systems are usually built on arid land, away from settlements. Since there is an inverse relation between the size of a settlement and the aridness of a field, renewable energy systems, particularly wind and solar, are far from major settlements and industrial facilities. This creates and increases transfer/transmit and storage duties. Accordingly, additional costs arise. The additional costs and hardship undermine the transition to a carbon dioxide neutral circular sustainable life. Another thing about the location of renewables on land is that transmitting generated energy may not be possible at all. Consequently, offshore renewable energy systems are being studied and also applied. In the present work, we review the concurrent literature about offshore floating wind turbines, present an idea on them, and lay out basic equations for evaluating the idea based on economics and physics.
2st International EUROSA Conference, 2024
Arrays of offshore renewables are being studied by academia to justify them economically in real-... more Arrays of offshore renewables are being studied by academia to justify them economically in real-world applications by private sector entities. Offshore renewables' initial and levelized costs are significantly higher than their on-land counterparts. Therefore, energy density per unit area should be dramatically increased and/or cost lowered. However, concurrent knowledge of offshore industries other than renewable energy, such as fish farms, offshore oil platforms, and marine shipping, implies that lowering costs will not be sufficient. In order to increase the energy density per unit area, multiple offshore renewable energy systems relying on different physics should be combined in threedimensional space, thus creating an array. Also, systems and structures of other marine industries can be included in the concept to benefit from their readily present infrastructure. Such arrays are the subject of scientific and engineering investigation and assessment since hydrodynamics, aerodynamics, mechanics, and economics are involved. The topic is highly multidisciplinary. In this work, we reflect on the present situation and project future aspects.
XIV International Conference on Industrial Engineering and Environmental, 2024
The field of biomimetics aims to develop innovative technical and engineering solutions by replic... more The field of biomimetics aims to develop innovative technical and engineering solutions by replicating systems, structures, and functions found in nature. Research in this domain focuses on the highly efficient and sustainable systems found in living organisms created by God over millions of years, seeking novel approaches to address human challenges. A key area within biomimetics is fluid mechanics, which explores how living organisms interact with fluid environments to inspire creative and efficient technological advancements. The multidisciplinary goal of these efforts is to design hydrodynamic and aerodynamic systems influenced by nature's mastery of fluid dynamics. Examples include the microstructure of shark skin, which reduces friction and enables swift and silent movement; the aerodynamic capabilities of birds and insects, which have influenced the design of aircraft wings and wind turbines; and the aquatic locomotion of fish and marine mammals, which has inspired the development of low-drag surfaces and efficient propulsion systems. In conclusion, the synergy between biomimetics and fluid mechanics contributes to the creation of more sustainable, energyefficient fluid systems, construction materials, and transportation technologies.
Journal of Polytechnic, 2023
The optimum tilt angle for a photovoltaic (PV) system depends on the row spacing because it affec... more The optimum tilt angle for a photovoltaic (PV) system depends on the row spacing because it affects the amount of shading on the panels. This study modeled PV systems for four different panel row spacings of 2 m, 2.5 m, 3 m, and 4 m in a fixed 3000 m² area in Konya province, Turkey. For different panel row spacings, the system performances were compared using a constant tilt angle of 35°, expressed as a proper angle for PV installations at the considered location. In addition, the optimum tilt angle is found for four different cases in terms of electricity generation. In systems with 35° tilt angles at electricity were produced annually as 622.77 MWh, 566.49 MWh, 495.36 MWh, and 385.72 MWh, respectively, for panel row spacings of 2 m, 2.5 m, 3 m, and 4 m. In addition, these electricity productions are 6.19%, 4.41%, 2.56%, and 0.92% higher with optimum tilt angles as 1°, 15°, 21° and 27°. Similarly, the Performance Ratio (PR) values obtained with the optimum angles are 20.61%, 8.39%, 4.12%, and 1.44%, higher than the fixed tilt angle cases. According to the economic analysis, systems with a fixed tilt angle for these panel row spacings pay back themselves in 5.13, 4.67, 4.44, and 4.28 years, respectively, while systems at optimum angles pay back themselves in a shorter time by 5.83%, 4.26%, 2.49%, and 0.91%. Furthermore, the highest NPV/INV, IRR, and ROI values were obtained from the system with 3 m panel row spacing with the optimum tilt angle of 21° as 0.915, 20.42%, and 91.57%, respectively, which is techno economically found to be the most feasible case.
In this study, an impeller and a volute of a centrifugal pump were re-designed and numerically an... more In this study, an impeller and a volute of a centrifugal pump were re-designed and numerically analyzed in respect of their performances. Initially numerical and experimental examinations of the original pump in production were done. For numerical studies, k-ε turbulence model and non-equilibrium wall function were utilized. Boundary conditions were taken as volumetric flow rate at inlet and head height at outlet. A rotational motion was defined for hub, shroud, blades and impeller solid models. The volumetric flow rate of 100 m /h,, head of 18 mWc and the impeller speed 1480 rpm were taken as design parameters. Experimental and computational results were compared for old designed pump. After the inspection of the flow field in the old pump, many geometrical modifications were made to design new pump. Impeller exit diameter, impeller entrance diameter, blade entrance and exit angles, blade wrap angle, blade entrance and exit widths, blade thickness of the old design were altered for a new design. A new volute was also designed according to newly designed impeller. While 18.0 mWc was attained for the Q =100 m / h via numerical analyses, 17.5 mWc was measured for the old selling design for the same volumetric flow rate. Despite this relatively small reduction in head height, hydraulic torque value of newly designed pump was calculated as 51.09 Nm while it was measured as 56.59 Nm for old design. This means that energy consumption of the pump can be decreased approximately 9.7%. Hydraulic efficiency values for old and new designed pumps were respectively found to be 55.98% and 63.09%, which corresponds to 11.26% hydraulic efficiency improvement.
Applied Engineering Letters : Journal of Engineering and Applied Sciences, 2023
This study modeled monocrystalline (mono-Si), polycrystalline (poly-Si), and amorphous silicon (a... more This study modeled monocrystalline (mono-Si), polycrystalline (poly-Si), and amorphous silicon (a-Si) Photovoltaic (PV) systems with a 300 kWp installed power using PVsyst software in Konya province, Turkey. The system’s electricity generation was calculated and compared with different PV technologies. In addition, an economic analysis for a 25 year lifespan was made with the obtained data. The annual global horizontal radiation (GI) and effective global irradiation (GE) are found to be 2001.7 kWh/m2 and 1949.6 kWh/m2, respectively. The highest yearly total electricity production was obtained from mono-Si, with a value of 513.91 MWh. This value is 1.91% and 3.07% higher than poly-Si and a-Si, respectively. Since the Performance Ratio (PR) values are proportional to the generated electricity and incoming irradiation to the surface of the PV panels, it calculated 0.853, 0.847, and 0.830 for mono-Si, poly-Si, and a-Si, respectively. According to the basic payback method, the economic analysis showed that mono-Si and poly-Si pay off in about 5.8-5.9 years, while a-Si pays off in 9,1 years. A net profit of
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Papers by Muharrem Hilmi Aksoy