INVESTIGATION ON THE AIR-GAS CHARACTERISTICS OF AIR-HYDROGEN MIXER DESIGNED FOR DUAL FUEL – ENGINES

High smoke emissions, nitrogen oxide and particulate matter typically produced by diesel engines. Diminishing the exhausted emissions without doing any significant changes in their mechanical configuration is a challenging subject. Thus, adding hydrogen to the traditional fuel would be the best practical choice to ameliorate diesel engines performance and reduce emissions. The air hydrogen mixer is an essential part of converting the diesel engine to work under dual fuel mode (hydrogen-diesel) without any engine modification. In this study, the Air-hydrogen mixer is developed to get a homogenous mixture for hydrogen with air and a stoichiometric air-fuel ratio according to the speed of the engine. The mixer depends on the balance between the force exerted on the head surface of the valve and the opposite forces (the spring and friction forces) and its relation to decrease and increase the fuel inlet. Computational fluid dynamics (CFD) analysis software was utilised to study the hydrogen and airflow behaviour inside the mixer, established by 3.2 L engine. The Air-hydrogen mixer is examined with different speeds of engine1000, 2000, 3000 and 4000 RPM. Results showed air-hydrogen mixture was homogenous in the mixer. Furthermore, the stoichiometric air-fuel ratio was achieved according to the speed of the engine, the developed mixer of the AIR-Hydrogen mixing process provides high mixing homogeneity and engines with stoichiometric air-fuel ratios, which subsequently contributes to the high levels of efficiency in engine operation. In summary, the current study intends to reduce the emissions of gases and offer a wide range of new alternative fuels usage. While the performance of the diesel engine with the new air-hydrogen mixer needs to be tested practically

Predicting and modeling the effects of turbines noise on operator’s mental task performance in AL-DORA power plant

Noise has become one of the most critical environmental challenges. As one of noise kinds, the discomfort level of environmental noise can affect both personal quality of life and hearing sensitivity. An example is workplace noise pollution, which affects employees' regular functioning and profoundly impacts their mental, auditory health, and psychological well-being. In order to tackle these issues, the need for adaptive intelligent systems has significantly grown. This study aims to evolve a neuro-fuzzy model for predicting the effects of noise pollution on employee’s work efficiency as a function of noise level and exposure time at Al-DORA Power Plant in Baghdad city. Participants' responses were used to develop a neural-fuzzy logic model based on artificial neural networks (ANN) and fuzzy inference systems (FIS). The model is performed using the fuzzy logic toolbox inherited from the MATLAB software. The measurements were carried out for duration of nine weeks, three times a day during summer, and the extensive noise level was up to 110 dB. Results in the trapezoidal-shaped membership form showed a discernible pattern or trend in the fluctuation of membership degree in relation to noise levels. The same trend could be seen for the exposure time. Furthermore, the results showed that the efficiency of the workers depends on the noise level and exposure duration. It has been confirmed that a medium noise level can influence workers’ performance over a medium exposure time to a certain degree. Moreover, low noise levels can still affect the performance of workers who are exposed to noise for long durations. With this clear relationship between noise levels, exposure time, and mental work efficiency, organizations can implement certain strategies to optimize their acoustic environment

A numerical study to improve the position and angle of the producer gas injector inside the intake manifold to minimize emissions and efficiency enhancement of a bi engine

To develop a petrol engine so that it works under the bi-engine pattern (producer gas-petrol) without any additional engine modifications, a single-point injection method inside the intake manifold is a simple and inexpensive method. Still, it leads to poor mixing performance between the air and producer gas. This deficiency can cause unsatisfactory engine performance and high exhaust emissions. In order to improve the mixing inside the intake manifold, nine separate cases were modelled to evaluate the impact of the position and angle orientation inside the intake manifold on the uniformity and spread of the mixture under AFR=2.07. A petrol engine (1.6 L), the maximum engine speed (8000 rpm), and bi-engine mode (petrol-producer gas engine). The employ of the numerical simulation software (ANSYS workbench 19), the propagation, flow characteristics, and uniformity of the blend within the nine different cases were evaluated. According to the outcomes of the numerical simulation, it was found that creating vortices and turbulent flow for the producer gas and air inside the intake manifold is the perfect method to obtain a uniformity mixture of air and producer gas inside the intake manifold. In addition, extending the blending duration allows air and producer gas fuel to be mixed efficiently. Furthermore, the greatest uniformity and the maximum spread rate at the outlet of manifold are obtained in cases 1, 4, and 7, when the producer gas injector location is constant (P1, P2 or P3). In addition, the weakest spread of producer gas at the outlet of the manifold is observed in case 9 in comparison with the other cases. Moreover, it is observed that case (1) generated the maximum uniformity index (UI) leve

An Empirical Model for Optimizing the Sound Absorption of Single Layer MPP Based on Response Surface Methodology

Micro-perforated panel (MPP) is a thin panel absorber capable of absorbing sound energy at a targeted frequency range by adjusting the MPP parameters. An analytical model is available, but it is not a direct, convenient method for practitioners to determine the required MPP parameters. This paper presents an optimized empirical model to calculate the sound absorption coefficient of a single-layer MPP.  The response surface methodology is employed for a simple case to generate a second-order polynomial model through a sequence of designing processes to analyze the functional relationships and variation of the outcome performance (sound absorption coefficient) concerning the MPP parameters, namely the panel thickness, hole diameter, perforation ratio, and the depth of the back air layer.  The analysis is carried out for frequencies between 300 to 900 Hz. The predicted data (empirical) is compared with the actual data (analytical), leading to a coefficient of variation of 0.145%. The proposed empirical model can be used as a method to select the suitable MPP parameters according to the targeted frequency bandwidth of absorption with less computational time

Impact of Lambda Value on Combustion Characteristics and Emissions of Syngas-Diesel Dual-Fuel Engine

A deep understanding of the ignition characteristics of syngas-diesel under different lambda values is essential for the application of dual-fuel combustion. In this study, the effect of increasing the lambda value was examined along with the emission characteristics and engine performance of syngas-diesel dual-fuel engines under a constant syngas-to-diesel substitution ratio of 52% at 2000 rpm engine speed. The work involved computational fluid dynamics analysis related to combustion for a four-stroke single-cylinder direct-injection engine. Combustion analysis was carried out using ANSYS Workbench (FLUENT) V16.1 software. According to the simulation results, the maximum pressure, temperature, and nitric oxide emission inside the combustion chamber increased with each increase in the value of lambda, while the emission of carbon dioxide and carbon monoxide decreased inside the engine

Експериментальна оцінка ефективності системи нагріву води для побутових потреб в кліматичних умовах Багдаду

The aim of the current study is to evaluate the performance of a domestic water heating system for residential areas in Baghdad climatic conditions for substituting electric water heaters with solar-powered water heaters using solar collectors. Many countries, such as Iraq, are sluggish with electric power issues while receiving very high solar insolation. Solar energy is a clean, non-depleting and low-cost source that can be used especially in residential areas, which forms a great percentage of energy consumption by replacing electric water heating with solar water heating to reduce electricity usage. Therefore, six flat plate solar collectors with an absorbing area of 1.92×0.85 m with one 4 mm thick glass cover are utilized for experimental investigation under the Baghdad climatic conditions. The collector was tested under steady-state settings, which assumed that sunlight intensity, ambient temperature, and inlet-outdoor temperature difference in each collector in the system were constant throughout the operation. According to the experimental results, during the test months of November, December, January, and February, the time-weighted experimental daily average collector array efficiency is found in the range of 40 % to 60 %. Furthermore, the greater energy gain and performance of the solar collector array attain a peak value at solar noon. Additionally, a solar collector with flat plates can easily achieve relatively high water temperature levels of 70 °C in the winter season. In addition, using a solar domestic hot water system as a water heater in Baghdad climatic conditions by substituting electric water heaters is useful for saving power consumptionМетою даного дослідження є оцінка ефективності системи нагріву води для побутових потреб житлових районів у кліматичних умовах Багдаду для заміни електричних водонагрівачів на сонячні з використанням сонячних колекторів. Багато країн, таких як Ірак, приділяють мало уваги проблемам електропостачання, отримуючи при цьому дуже високу сонячну інсоляцію. Сонячна енергія є екологічно чистим, невичерпним і недорогим джерелом енергії, що може бути використана зокрема у житлових районах, де утворюється великий відсоток споживання енергії за рахунок заміни електричного нагріву води сонячним нагріванням для зниження споживання електроенергії. Тому для експериментальних досліджень у кліматичних умовах Багдаду використано шість плоских сонячних колекторів з площею поглинання 1,92×0,85 м з одним скляним покриттям товщиною 4 мм. Випробування колектора були проведені в усталених режимах, при яких передбачалося, що інтенсивність сонячного світла, температура навколишнього середовища і різниця температур на вході та виході в кожному колекторі системи були постійними протягом усього періоду роботи. Згідно з результатами експериментів, протягом випробувальних місяців листопад, грудень, січень та лютий зважена за часом експериментальна середньодобова ефективність колекторної системи знаходиться в межах від 40 % до 60 %. Приріст енергії та продуктивність системи сонячних колекторів досягають пікового значення у сонячний полудень. Також, плоский сонячний колектор дозволяє легко досягати відносно високих рівнів температури води 70 °C у зимовий сезон. Крім того, використання сонячної системи гарячого водопостачання в якості водонагрівача в кліматичних умовах Багдаду шляхом заміни електричних водонагрівачів забезпечує економію споживаної енергі