2022
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Item Comparative Design Analysis of Motorcycle Braking Systems to Decide the Most Appropriate System According to The Traffic Context of Bangladesh(Department of Mechanical and Production Engineering, Islamic University of Technology, Gazipur, Bangladesh, 2022-05-30) Mahtab, Md.Azmain; Mahee, Nafiz Fuad; Shikder, Md.NahianThe road accident rates in Bangladesh has increased by 42% since last 4 decades. Apart from all other socio-economic reasons, lack of appropriate usage of motorcycle braking system is one of the obvious reasons in this phenomenon. Hence, suitable braking system can contribute vastly in reducing accidents and accident rates. As there are lots of braking systems available for motorcycle in today’s market, it is difficult for general people to identify the proper vehicle which is compatible to the road and traffic conditions in our country. In this paper, design aspects and working methods of different types of motorcycle braking system have been scrutinized based on data and graphical analysis. And finally authors have tried to reach a probable decision about the most fit braking system in Bangladesh that can be incorporated with the motorcycle. The result of this paper can help further research on the country specific motorcycle braking system in Bangladesh as it represents a comparative analysis between Anti-Lock braking system and other systems. And eventually proved the Probable higher efficiency rate of ABS in terms of Theoretical discussion.Item Study and comparison of mechanical properties between scrap recycled steel and ship recycled steel.(Department of Mechanical and Production Engineering, Islamic University of Technology, Gazipur, Bangladesh, 2022-05-30) Al-Noor, M. Sadik; Shuvo, Safayet Hossen; Khan, TausifSteel is the most recycled metal in the world and it is impossible to imagine life without steel. It must be recycled maintaining its proper quality and contributing to economy. Scrap recycling and ship recycling are two processes for all of the steel recycling. Which recycling process is more sustainable in terms of quality is to be found out. Quality of steel refers to its mechanical properties. So, there has to be a logical comparison between these two types of recycled steel. It will indicate which type of steel is more suitable for different applications of steel. When the data of both recycled is available, it is easy to determine the suitable steel to meet the desired properties (i.e. yield strength, torsional strength) of steel. However, these data must be reliable based on proper sample, precious scientific experiment and obviously outright comparison between scrap recycled steel and ship recycled steel. It is very significant to execute the experiments with accuracy and precision as it has large scale practical implication. Moreover, different operations must be conducted very carefully in order to manufacture appropriate specimen from the collected sample of steel from the industries. In this paper, our sample size is not so much large. As a result, it is recommended to collect large number of samples from different industries in case of further study on this field. Only ensuring the quality is not enough, economic viability also must be checked. In this paper, economic feasibility for recommended steel is also considered. Some field of steel application one particular mechanical property (i.e., yield strength) is desired to be maximum and if we know which types of recycled steel possess that particular mechanical property better and use it on that field, desired quality will be fulfilled. The paper is based on more experimental and recommending mass practical application.Item A CFD Study on Comparison of Heat Transfer Performance of Water based Graphene Nanoplatelets Nanofluids and Multiwalled Carbon Nanotubes Nanofluids in a Concentric Tube Heat Exchanger(Department of Mechanical and Production Engineering, Islamic University of Technology, Gazipur, Bangladesh, 2022-05-30) Hoq, MD ZahinulFor the next generation of nanofluids, carbon nanomaterials are of tremendous interest. CnT and GnP, in particular, are extremely thermally conductive, and their usage in heat transfer nanofluids is a significant field of study. Using a concentric tube annular heat exchanger in the same operating circumstances, the heat transfer performance of GnP-nanofluid and MWCNT-nanofluid was investigated in this study. In the inner tube, the manufactured nanofluid flowed as a hot fluid in the reverse direction of a colder water flow in the annulus tube. The flow rate (1.5 L/min – 2.5 L/min) and concentration (0.01% – 0.35%) of nanofluid were varied in the experiment. At the same flow rates and nanofluid concentrations, the heat transfer coefficient of GnP-nanofluid was found to be greater than that of MWCNT-nanofluid. When an appropriate volumetric concentration is attained in both nanofluids, the favorable influence on heat transfer performance increase is at its peak. In comparison to MWCNT, our research reveals that GnP can increase heat transfer coefficient at lower volumetric concentrations and flow ratesItem Power Generation from Rice Husk(Department of Mechanical and Production Engineering(MPE), Islamic University of Technology(IUT), 2022-05-31) Anando, Ahmed ImtiazThe alarming rate at which the deposit of non-renewable or fossil energy resources are depleting around the whole world has been nudging us in the direction of green energy for quite a long time. Considering the upcoming energy crisis in the near future, we have no choice but to divert our focus on renewable energy resources to meet the power demand of an ever-growing global population and industry. Rice husk is a by-product of producing rice from paddy which is consisted of about 20% mass percentage of rice. It is a biomass with low energy density and low bulk density. Due to these properties, it is not efficient or viable to directly combust rice husk as a fuel. In order to improve the fuel characteristics of rice husk and convert it into a coal-like fuel, different thermochemical pretreatment technologies can be implemented. Previously, there have been many studies and researches on pretreatments of rice husk. Most of these studies were experimental. This paper reviews four of the most common of such technologies namely, gasification, torrefaction, pyrolysis and hydrothermal carbonization including multiple sub-categories of each technology. All of these processes are successful in improving the fuel characteristics of rice husk such as higher heating value or calorific value, moisture content, fixed carbon, etc. The second section of the thesis covers the field of power generation using the pretreated rice husk samples as fuels. For the simulation, Recompressed Supercritical CO2 Brayton Cycle with Reheating was chosen. A basic comparison among different pretreatments was shown in terms of power output from the cycle when rice husk undergone corresponding pretreatments was used as fuel for the heat input. The economic and exergy analysis of the thermochemical processes were out of the scope of this thesis thus, this study only focuses on the energy analysis of producing power from rice husk. The results found out of the study shows that each of the thermochemical processes has its own advantages and serves the goal, which is to improve the fuel properties of rice husk. Further investigation on other aspects can help the community understand which process will be better suited for a particular purpose.Item CFD Modelling of H-Darrieus Vertical Axis Wind Turbine(Department of Mechanical and Production Engineering(MPE), Islamic University of Technology(IUT), 2022-05-31) Tonni, Morium MannanWith the progress of time, as fossil fuel is being exhausted, renewable energy resources are getting more attention for their promising impact on the environment and its capability to replenish and sustainability. Wind energy is one of the most important renewable energy sources. A study shows that installed wind capacity increases by more than 30% every year. Design improvement of wind turbines has many parameters to consider for optimization. Experimental analysis is complex and not always feasible. But numerical simulation has the ability to analyze different parameters with less complexity. In this thesis, a 2D CFD simulation of an H-Darrieus vertical axis wind turbine is done. Prior to the simulation, mesh independent and time independent study was done not only to validate the result but also to reduce the computational effort. Sliding Mesh model approach was used for simulation which takes into account the vortices generated by the blades passing upwind on the blades downstream unlike over-simplified Moving Reference Frame (MRF) model. The transition SST model was used as the turbulence model which utilizes the advantages of both k-ε and k-ω models, providing better simulation results. From the simulation results, a Power co-efficient (Cp) vs Tip speed ratio λ curve was obtained and was validated against existing experimental data available in the literature. The knowledge obtained from this thesis can lead to the development of improved 2D simulations and ultimately 3D simulations in the future. This can also be used for design optimization and performance study of wind turbines.Item Vibration and Stress Analysis of Multistory Steel Structure(Department of Mechanical and Production Engineering(MPE), Islamic University of Technology(IUT), 2022-05-31) Alvy, Tamzeed AhmedModal parameters of structures and machines is crucial to determine the dynamic behavior during operation stages. A necessary step is to determine the dynamic characteristics and optimize the structure at its design phase to prevent any catastrophic failure. So, the purpose of this study is to focus on the modal parameters of steel structures both numerically and with experimentation and to shed some light on the equivalent stresses developed in the structure through numerical methods. Not only the modal parameters have been determined, but also the validation of the results through experiment. This will allow for accurate analysis on high-rise steel structures numerically without doing costly experiments. The mode shapes and natural frequencies of the 4-story structure for both loaded and unloaded conditions have been found through simulation in ANSYS. The first 6 modes have been extracted as these have been seen to affect the structure the most during dynamic loading condition such as earthquakes. These modal parameters have been validated using experimental method using a model 2-story structure through harmonic analysis. And finally, Von Mises stress analysis has been performed to find the relative stresses developed in the 4-story unloaded structure during different mode shapes and natural frequencies. From the research, the simulation results have been validated using the experimental data. And from the different loading condition of the structure, the different mode shapes and natural frequencies have been found. As the loading is changing from floor to floor, so is the change in mode shapes and natural frequencies. The shapes and natural frequencies greatly vary from the unloaded structure. The novelty of the research is that the modal parameters due to different loading conditions and compared those with an unloaded structure.Item Changes in future rainfall extremes over northwest Bangladesh using multi-model ensemble(Department of Mechanical and Production Engineering(MPE), Islamic University of Technology(IUT), 2022-05-31) Abedin, MD MinhajulBangladesh is rich in nearly every form of natural resource. Underground water and rainfall are critical parameters in civil and mechanical engineering. The impacts of climate change on precipitation across Bangladesh's northwestern zone were explored using daily precipitation data from eight bias-corrected general circulation models (GCMs) under the representative concentration pathway (RCP) 4.5 and RCP 8.5 scenarios. The northwestern zone is particularly prone to drought. CMIP5 models perform a probabilistic forecast of the future using the precipitation indices for the time period of (2010-2099). We will forecast changes in future climate indices for the period 2020-2099 using observed data and GCM model data. Future timespan can be separated into two sections: one is the near future (2020-2059) and another one is the far future (2060-2099). Menn-Kendell Test will give us future trend analysis report. Bayesian Model Averaging (BMA) will be used to do multi-model ensemble. Changes in extreme climate indices will be projected by spatial mapping. Extremely heavy precipitation days & heavy precipitation days are decreasing in almost all stations. But total annual precipitation has an increasing trend. For high emission scenario change in climate indices are more prominent & devastating. These are the major findings of this thesis. Our study only focuses on precipitation. But temperaturerelated indices are skipped in this case due to time shortage. So, giving a perfect future climate scenario is quite tough. It’s a major limitation in our study. But we see that most of the cases the indices are changing insignificantly in Ishwardi station. In some cases, Rangpur & Dinajpur will face some extreme weather events.Item Design and off-Design Performance Analysis of a Zigzag Channeled Precooler For SCO2 Recompression Cycle Integrated with CSP(Department of Mechanical and Production Engineering(MPE), Islamic University of Technology(IUT), 2022-05-31) Ahmed, Md. MarufThe design and performance analysis of Printed Circuit Heat Exchanger (PCHE) as pre-cooler is being recent research trend as the researches on recuperator has already been saturated. The improbable fluctuating properties of sCO2 near the critical region makes it arduous to design a component that runs under the critical region. However, the high heat transfer coefficient at near critical region is advantageous in increasing the second law efficiency of the power cycle and reducing the size of cycle components, making it cost effective. In this study an iterative nodal approach is implemented to develop a design code in Python language for the design of zigzag channeled PCHE as the pre-cooler for sCO2 recompression cycle integrated with Concentrated Solar Power technology. For the real gas properties (RGP) of sCO2 CoolProp is used. The performance study done under different sCO2 inlet pressure and different water inlet temperature suggest the heat transfer rate can be enhanced by lowering the water inlet temperature and sCO2 pressure down to 7.5MPa. The result also shows the pressure drop on SCO2 side decreases upon increasing these parameters. The outcomes derived from this work can be used to design and develop more advanced PCHEs for pre-cooler application for wide range of Cooling-loads.Item Numerical Investigation of a Hybrid Photovoltaic Thermal PVT Module(Department of Mechanical and Production Engineering, Islamic University of Technology, Gazipur, Bangladesh, 2022-05-31) Chowdhury, Taspia Shawkat; Mita, Mita Noor Hasan; Mohsin, Fatima TasneemOver 173,000 terawatts of solar radiation continuously strike the Earth’s atmosphere however, most of this energy is reflected or absorbed and is lost due to insufficient space and technology required to harness the solar energy and generate electricity. Photovoltaic (PV) solar panels are widely used globally to receive light energy from solar irradiance and convert it to electricity. PV cells are designed to absorb as much as 80 percent of the insolation energy however, due to structural limitations only 10-15 % of this incident solar radiation is converted to electricity with most of this absorbed energy converting to heat and raising the temperature of the entire module and greatly reducing the efficiency of electricity generation. This undesirable reduction in electrical efficiency is avoided by the addition of a heat recovery system to the PV module to cool the panel and effectively extract waste heat to enhance both thermal and electrical efficiency. Such modified PV modules are known as hybrid PV module or Photovoltaic thermal systems. The primary purpose of this research is to numerically validate the effectiveness of various ribbed surfaces in enhancing the thermal efficiency of the dual hybrid PVT system by simultaneously using both air and liquid water as cooling fluids. In addition, the effect of water and air velocities on thermal efficiency have also been observed by monitoring the temperatures at water outlet. The findings indicate significant reduction in the water outlet temperature with increasing water velocity and decreasing air velocity drawing the conclusion that the air velocity maximized, and water should be passed at a low velocity to achieve higher heat transfer rates. The utilization of ribbed surfaces substantially improved thermal performance with the semicircular and triangular ribbed surfaces achieving higher water outlet temperature at all solar heat flux throughout the day. Highest water outlet temperature and thus heat transfer was observed to be occurred at 1:00 P.M when the heat flux from the sun is maximum. The numerical findings successfully conformed with the data obtained from the experiment and conform to the results from previous research works. Finally, this study provides a comprehensive comparison between the different geometries of the PVT module and determines the optimum operating conditions for optimized thermal efficiency of the PVT module.Item Thermal and Hydraulic Performance Comparison of Carbon Based and Metal Based Nano fluids in Flat Plate Solar Collector: A CFD Analysis(Department of Mechanical and Production Engineering, Islamic University of Technology, Gazipur, Bangladesh, 2022-05-31) Nuhash, Mashrur Muntasir; Alam, Md. Ibthisum; Zihad, AnantaThe constant rise in global temperature and the need to reduce fossil fuel consumption has made renewable energy sources desirable, especially solar energy systems. Flat plate solar collector (FPSC) is one of the most established solar energy technologies for lower to medium heat applications. FPSC has a wide range of implications because of their beneficiary of simple structure and low maintenance although the low thermal efficiency of the conventional system hinders their further development. The utilization of nanofluid as the heat transfer fluid in FPSC has been a popular trend for the last decades and significant improvements in the performance using this technique have been observed. Due to their better thermo-physical properties, carbon-based nanofluid possesses greater prospects compared to metal-based nanofluid. However, this subject matter has not been explored further yet. This study develops a CFD model to assess the performance of a metal-based based nanofluid (Al2O3/water) and two carbon-based nanofluids (SWCNT/water and MWCNT/water) at volume concentrations up to 1% in a simple FPSC. Based on thermal-hydraulic properties, a detailed comparison among these three nanofluids is made. The observation was, that, with the elevation of Reynolds number (Re) and volume concentrations the outlet temperature decreases and among the nanofluids Al2O3/water showed the lowest reduction. The types of nanofluids do not influence the friction factor. It was noticed that the friction factor decreases with the increase of Re while higher volume concentration necessitates greater pumping power. SWCNT/water nanofluid showed the best results in terms of heat transfer coefficient and Nusselt number followed by Al2O3/water and MWCNT/water. For enhancing both the Re and volume concentration the heat transfer coefficient is boosted. But for the Nu, the values rose with the higher Re while it deteriorated with the increasing volume concentration. The highest Stanton number was achieved for greater volume concentration and smaller Re. In the case of the thermal-hydraulic performance parameter (THPP) the values increased with higher volume concentrations although the Re had a negligible impact on it. The analysis indicates the SWCNT/water is the best performing nanofluid but requires a higher pumping power. This study concludes that carbon-based nanofluid outperforms metal-based nanofluid at both inlet temperatures of 303K and 313K. These findings from the study will be beneficial in future design of efficient solar thermal applications.