Master of Science (MS), Ohio University, 2009, Mechanical Engineering (Engineering and Technology)

The increasing concerns related to long term availability of petroleum-based fuels and the emissions from diesel-powered vehicles have given rise to a growing search for an alternate source of fuels for use in diesel vehicles. One of the most recent and promising findings in this field is “Bio-diesel”. The thesis uses a comparative study of NOx emission characteristics for regular diesel fuel and soy based biodiesel for a four cylinder, 60 HP turbocharged diesel engine for validation of the engine and the emission test rig. Modifications are recommended for the current test setup and test procedure to enable research quality testing of Algae based biodiesel.

Committee: Gregory G Kremer (Advisor); David Bayless (Committee Member); Ben Stuart (Committee Member); Helmut Paschold (Committee Member) Subjects: Mechanical Engineering

PhD, University of Cincinnati, 2018, Engineering and Applied Science: Aerospace Engineering

A generic novel injector was designed for multi-Lean Direct Injection (M-LDI) combustors. One of the drawbacks of the conventional pressure swirl and prefilming type airblast atomizers is the difficulty of obtaining a uniform liquid sheet under all operating conditions. Micro-channels are needed inside the injector for uniformly distributing the fuel. The problem of non-uniformity is magnified in smaller sized injectors. The non-uniform liquid sheet causes local fuel rich/lean zones leading to higher NOx emissions. To overcome these problems, a novel fuel injector was designed to improve the fuel delivery by using a porous stainless-steel material with 30 µm porosity. The porous tube also acted as a prefilming surface. Liquid and gaseous fuels can be injected through the injector. The current study investigates the aerodynamics, spray quality, fuel-air mixing and emission characteristics of the novel injectors at 4% pressure drop and atmospheric conditions. The injectors have two configurations with different counter-rotating radial-radial swirlers. And the injector 1 has a SN of 0.75 and SN of injector 2 is 0.6. The characteristics of the novel injectors are also compared with a typical airblast injector having a peanut nozzle with flow number of 1. A Central Toroidal Recirculation Zone (CTRZ) and Corner Recirculation Zone (CRZ) are observed from the aerodynamics study. Spray measurements are carried out at various equivalence ratio conditions without a confinement. D10, D32 and D0.5 are investigated on Jet-A, GTL and blended fuels. There is no significant influence of fuel types on the spray behavior due to their similar physics properties. The porous injectors generate a fine spray with weighted SMD ~45 µm at equivalence ratio of 0.6. Gaseous Fuel-air mixing studies are carried out at different equivalence ratios with and without a confinement. A fully premixed mixing profile was obtained at 0.43” downstream of the injector exit. Flame characterization (open full item for complete abstract)

Committee: San-Mou Jeng Ph.D. (Committee Chair); Jun Cai Ph.D. (Committee Member); Jongguen Lee Ph.D. (Committee Member); Bassam Mohammad Abdelnabi Ph.D. (Committee Member) Subjects: Aerospace Materials

Master of Science, University of Toledo, 2018, Civil Engineering

The main objective of this experimental thesis was to present a comprehensive analysis of exhaust emissions from transit buses during daily routine operations. The pollutants monitored in this study are Particulate Matter (PM), NOx, CO2, and HC released from three different buses with different exhaust control systems such as NON-EGR bus, EGR- bus with EGR+DPF+DOC and hybrid bus with EGR+DPF+DOC+SCR. All these buses were tested on the same route each day. To further categorize and elaborate our findings, the runtime was divided into both idle and running conditions. With a specific end goal to accomplish extensive outcomes, the idle condition was additionally divided into two distinct cases, i.e., cold idle and hot idle conditions. The running conditions were also divided into acceleration, deceleration, variable speed, and intersections. The NOx, CO2 and HC emission were gathered and analyzed for every one of the conditions and modes depicted above. The particulate emission was collected and analyzed in idle conditions. In idle condition NOx, CO2 and HC decrease with time and stay constant after they reach 15 minutes of idle time. The cold idle emissions are observed to be very high when compared to the hot idle condition, this is because the hot idle emissions are collected after the bus gets back to the garage from its daily route with a hot engine and this delivers the appropriate amount of fuel into the engine for complete combustion. Whereas cold idle mode does not run at its optimum temperature that leads to incomplete combustion and increases in emission formation. The NOx and HC emissions decreased from NON-EGR to EGR to the hybrid bus because of the emission control systems: SCR, DOC, and EGR, Whereas CO2 emissions, increase by using the same emissions control systems from NON-EGR to EGR to the hybrid bus. The study shows that hybrid bus emits less amount of NOx when compared to EGR and NON- EGR buses, this is because of the exhaust control syste (open full item for complete abstract)

Committee: Ashok Kumar (Committee Chair); Kim Dong Shik (Committee Co-Chair); Hu Liangbo (Committee Member) Subjects: Civil Engineering; Environmental Engineering

MS, University of Cincinnati, 2001, Engineering : Environmental Engineering

This paper summarizes the findings of a study on the effect of the chemical and physical properties of Ohio coals on NO x emissions, as well as combustion conditions that promote lower levels of pollutant release. The results were obtained in a drop-tube reactor under controlled laboratory conditions with well-characterized samples of Ohio coals. Ten Coal samples were obtained from the Penn State Coal Sample Bank and selected based on their levels of fixed carbon, volatility and nitrogen content. The heat contents of the 10 coals were similar. Tests on monodispersed sized coal particles were conducted in the ceramic drop-tube reactor at 1200°C and a gas residence time of 0.5 sec. The diameter of the ceramic drop tube reactor was 5.08 cm and its length was 110.5 cm. The air/fuel (A/F) ratio was maintained at 1.1 and the coal feed rate was 7 – 9 mg/min. The percent nitrogen in the raw coal ranged from 1.24 to 2.5%wt. For a majority of the experiments, samples were prepared in sizes between 15 to 25 micrometers. From the experimental results, it was found that relative NO x emissions varied by as much as 100% and that a linear relationship exists between relative NO x formation and the chemical and physical properties of Ohio coals. NO x emissions depend on the properties of fixed carbon (FC), volatile matter (VM) and nitrogen (N) in the raw coals. As a result, relative NO x gas emissions were predicted, which may be useful in terms of coal selection for any source using Ohio coals.

Committee: Dr. Tim C. Keener (Advisor) Subjects: Engineering, Environmental