Rodriguez, Alvaro Diez
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03.10. Department of Mechanical Engineering
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Former Staff
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Sustainable Development Goals
1NO POVERTY
1
Research Products
2ZERO HUNGER
1
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3GOOD HEALTH AND WELL-BEING
0
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4QUALITY EDUCATION
1
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5GENDER EQUALITY
0
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6CLEAN WATER AND SANITATION
2
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7AFFORDABLE AND CLEAN ENERGY
6
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8DECENT WORK AND ECONOMIC GROWTH
2
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9INDUSTRY, INNOVATION AND INFRASTRUCTURE
6
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10REDUCED INEQUALITIES
0
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11SUSTAINABLE CITIES AND COMMUNITIES
1
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12RESPONSIBLE CONSUMPTION AND PRODUCTION
2
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13CLIMATE ACTION
5
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14LIFE BELOW WATER
1
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15LIFE ON LAND
1
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16PEACE, JUSTICE AND STRONG INSTITUTIONS
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17PARTNERSHIPS FOR THE GOALS
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Scholarly Output
7
Articles
3
Views / Downloads
4892/2320
Supervised MSc Theses
4
Supervised PhD Theses
0
WoS Citation Count
26
Scopus Citation Count
32
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0
Projects
2
WoS Citations per Publication
3.71
Scopus Citations per Publication
4.57
Open Access Source
6
Supervised Theses
4
| Journal | Count |
|---|---|
| Biomass Conversion and Biorefinery | 2 |
| ACS Omega | 1 |
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7 results
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Now showing 1 - 7 of 7
Article Citation - WoS: 9Citation - Scopus: 11Experimental Investigation of Spray Characteristics of Ethyl Esters in a Constant Volume Chamber(Springer, 2024) Ulu, A.; Yildiz, G.; Özkol, Ü.; Rodriguez, A.D.Abstract: Biodiesels are mainly produced via the utilization of methanol in transesterification, which is the widespread biodiesel production process. The majority of this methanol is currently obtained from fossil resources, i.e. coal and natural gas. However, in contrast with methanol, biomass-based ethanol can also be used to produce biodiesels; this could allow the production line to become fully renewable. This study aimed to investigate the spray characteristics of various ethyl ester type biodiesels derived from sunflower and corn oils in comparison to methyl esters based on the same feedstocks and reference petroleum-based diesel. Spray penetration length (SPL) and spray cone angle (SCA) were experimentally evaluated in a constant volume chamber allowing optical access, under chamber pressures of 0, 5, 10 and 15 bar and injection pressures of 600 and 800 bar. Sauter mean diameter (SMD) values were estimated by using an analytical correlation. Consequently, ethyl esters performed longer SPL (2.8–20%) and narrower SCA (5.1–19%) than diesel under ambient pressures of 5 and 10 bar. Although the SMD values of ethyl esters were 48% higher than diesel on average, their macroscopic spray characteristics were very similar to those of diesel under 15 bar chamber pressure. Moreover, ethyl esters were found to be very similar to methyl esters in terms of spray characteristics. The differences in SPL, SCA and SMD values for both types of biodiesels were lower than 4%. When considering the uncertainty (± 0.84%) and repeatability (±5%) ratios, the difference between the spray characteristics of methyl and ethyl esters was not major. Graphical abstract: [Figure not available: see fulltext.] © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.Master Thesis A Numerical Study of Waste Heat Recovery Potential of the Exhaust Gases From a Power Generation Diesel Engine(Izmir Institute of Technology, 2017) Boz, Buket; Rodriguez, Alvaro DiezRecently, producing and using energy in an efficient way is one of the challenges through the world. Additionally, the severe environmental issues regarding global warming and ozone depletion have risen. Having taken into consideration two aspects, waste heat recovery systems can be an effective solution to solve some of these problems. This study presents the waste heat recovery potential applied to stationary internal combustion engines. Through the work, three different diesel engines’ exhaust gases are applied as the heat sources. Three Organic Rankine Cycle (ORC) configurations are designed, a Simple Organic Rankine Cycle and Regenerative Organic Rankine cycle which are thermally powered by exhaust gases and Pre-heating and Regenerative Organic Rankine Cycle with the usage of exhaust gas and the engine cooling water as the heat sources. In order to assess the differences between the chemical classes regarding the ozone depletion and global warming potential, eight candidate working fluids are chosen. A selecting procedure is created to obtain the most appropriate working fluid for the suitable cycle configuration. The first law of thermodynamic analysis is conducted with the variations of the working fluids, heat sources and the cycle designs in order to accomplish the greatest thermal efficiency with the most suitable working fluid and the configuration. It was found that it is possible to achieve a high thermal efficiency outcome using zero ozone depletion and global warming potential fluids under the Regenerative Organic Rankine configuration.Master Thesis An Adaptive Neuro-Fuzzy Approach for Modeling the Effects of Water-In Emulsion on Diesel Sprays(Izmir Institute of Technology, 2016) Yavuz, Bekir Kağan; Rodriguez, Alvaro Diez; Saplıoğlu, KemalThis thesis is prepared as an outcome of the Energy Engineering Master of Science program at Izmir Institute of Technology, IZTECH, in Turkey. The main purpose of this study is to analyse the effects of water content in diesel fuel spray behaviours using adaptive neuro-fuzzy inference system models (ANFIS) for compression ignition engines. The investigations are carried out using numerical models of ANFIS in MATLAB R2011a, generating simulations from training and test datasets based on recent experimental studies from the literature. The thesis primarily tests the use and the fitness of ANFIS models, modifying the neural network structure so that the simulations acceptably reach the experimental results accurately. Then secondarily, the simulation is used to investigate the effects of parameters originally not available in the related study. The investigation mainly focusses on water in diesel emulsions from pure diesel to an emulsion with 20% water content. Operational conditions such as chamber ambient pressure, injection pressure, chamber ambient temperature are also investigated to find their effects over spray penetration. It was found that the increase of water content in the diesel fuel did not have a relevant effect at very low and very high temperatures, however at medium-high temperatures it increased spray penetration. Furthermore, it was observed that the increase of chamber ambient pressure and chamber ambient temperature reduced the spray penetration as expected.Article Citation - WoS: 8Citation - Scopus: 10Spray Analysis of Biodiesels Derived From Various Biomass Resources in a Constant Volume Spray Chamber(American Chemical Society, 2022) Ulu, Anılcan; Yıldız, Güray; Rodriguez, Alvaro Diez; Özkol, ÜnverThis research aimed to analyze the spray characteristics of various biodiesels, which have rarely been investigated in terms of spray analysis in the literature compared to fossil diesel. For this purpose, four different methyl ester-type biodiesels were produced from canola, corn, cottonseed, and sunflower oils. These feedstocks were selected due to their wide availability in Turkey and being among the significant resources for biodiesel production. Measured physical properties of biodiesel samples showed that biodiesel fuels had, on average, 1.7 to 1.9 times higher viscosities, 5.3 to 6.6% larger densities, and 37 to 39.1% higher contact angle values than the reference diesel fuel. Spray characteristics of all fuels were experimentally examined in a constant volume spray chamber under chamber pressures of 0, 5, 10, and 15 bar and injection pressures of 600, 800, and 1000 bar. All tested biodiesels performed, on average, 3 to 20% longer spray penetration lengths, 5 to 30% narrower spray cone angles, and 5-18% lesser spray areas than the reference diesel fuel under chamber pressures of 5 and 10 bar. No significant differences occurred at 15 bar ambient pressure between biodiesels and diesel. In addition, analytical and empirical predictions showed that biodiesels had around 21.2-35.1% larger SMD values and approximately 7% lower air entrainment.Master Thesis Cogeneration Sustainability Study for the Izmir Institute of Technology(Izmir Institute of Technology, 2017) Ahmad, Awais; Rodriguez, Alvaro DiezIn this study, feasibility of Cogeneration/Combined Cycle System will be evaluated for the Izmir Institute of Technology. Turkish Energy Policy lacks some key factors which need to be highlighted for achieving Energy targets. The first aim of this study is to compare the policies and implementation of combined cycle systems of Turkey with Europe and to analyze the steps carried out by European Countries to achieve sustainability. The main objective of this study includes the implementation of a combined cycle system based on the data collection from the authorities of the Institute to analyze the deficiencies of existing system and to propose a more efficient system for meeting the energy demand. Two systems were taken in consideration, a gas turbine and a reciprocating engine based combined cycle system, detailed energy analysis with emissions and cost analysis were presented to determine what case provides the best solution to meet the energy demand.Master Thesis Experimental Investigation of Gdi Injectoer(Izmir Institute of Technology, 2015) Abuzahra, Fakhry; Rodriguez, Alvaro DiezAmong the challenges in the internal combustion - spark ignition Gasoline Direct Injection (GDI) engines stayed under spotlight for its ability to be developed in terms of fuel conversion efficiency and emission contaminants. Spray analysis is of great importance for the combustion operation and it is a prerequisite for improving the mixing capabilities of the air/fuel mixture. Momentum flux measurement technique is one of the most interesting approaches that aims to study the spray structure which can be a complement for high-speed imaging and Phase Doppler Anemometry (PDA) analysis. In the present study, two GDI single-hole research injectors, Magneti Marelli with Length to Diameter parameter (L/D)=1; 3 are investigated by means of momentum flux, global and local, under both low and high temperatures. The flash-boiling phenomenon is triggered when static pressure is below fuel saturation pressure at the same temperature which drastically affects the spray structure in terms of decrement in the penetration rate accompanied with an enlargement in the cone angle. N-heptane is used as a fuel under a temperature range 30-120 C, vessel ambient pressure range 40 303 KPa ,energizing time 1500 -3000 distance for the global momentum 5--40 mm and two horizontal planes for local momentum flux 10; 30 mm. Results of high-speed imaging were integrated in terms of cone angle and penetration rate. Furthermore, the results of this study can verify the Computational Fluid Dynamic (CFD) numerical analysis and provide wealthy understanding of the spray evolution.Article Citation - WoS: 9Citation - Scopus: 11Experimental Investigation of Spray Characteristics of Ethyl Esters in a Constant Volume Chamber(Springer, 2022) Ulu, Anılcan; Yıldız, Güray; Özkol, Ünver; Rodriguez, Alvaro DiezAbstract: Biodiesels are mainly produced via the utilization of methanol in transesterification, which is the widespread biodiesel production process. The majority of this methanol is currently obtained from fossil resources, i.e. coal and natural gas. However, in contrast with methanol, biomass-based ethanol can also be used to produce biodiesels; this could allow the production line to become fully renewable. This study aimed to investigate the spray characteristics of various ethyl ester type biodiesels derived from sunflower and corn oils in comparison to methyl esters based on the same feedstocks and reference petroleum-based diesel. Spray penetration length (SPL) and spray cone angle (SCA) were experimentally evaluated in a constant volume chamber allowing optical access, under chamber pressures of 0, 5, 10 and 15 bar and injection pressures of 600 and 800 bar. Sauter mean diameter (SMD) values were estimated by using an analytical correlation. Consequently, ethyl esters performed longer SPL (2.8–20%) and narrower SCA (5.1–19%) than diesel under ambient pressures of 5 and 10 bar. Although the SMD values of ethyl esters were 48% higher than diesel on average, their macroscopic spray characteristics were very similar to those of diesel under 15 bar chamber pressure. Moreover, ethyl esters were found to be very similar to methyl esters in terms of spray characteristics. The differences in SPL, SCA and SMD values for both types of biodiesels were lower than 4%. When considering the uncertainty (± 0.84%) and repeatability (±5%) ratios, the difference between the spray characteristics of methyl and ethyl esters was not major.