Journal of Research and Applications in Mechanical Engineering

Heat Transfer of MHD Non-Newtonian Fluid in Presence of Thermally Stratified Medium

2024-02-26T20:46:10+07:00

In this paper, investigated on heat transfer of MHD non-newtonian fluid in presence of thermally stratified medium. The momentum and energy equations associated with the partial differential equations are transformed into highly nonlinear ordinary differential equations by using similarity transformations. Kummer's function is used to represent the analytical solutions to these equations, and obtained the numerical solution of energy equation using analytical solution of flow. Numerical analysis carried out through BVP5C and ND Solver commands, and comparing with analytical method while using wolfram language mathematica and values are accurate. Graphically represented all physical parameters and also represented in Table form and Bar & Contour Graphs. In presence of thermal stratification, it is seen that the rate of surface heat transfer decreases whenever rising in viscoelastic and magnetic parameter, Prandtl number. Temperature distribution exhibits the reverse effect. Applications are geothermal & power plant condensation systems, geological transport, lake thermohydraulics, volcanic flows.

Estimation of the Fatigue Life of Test Specimens Made from Ferrous Metals Using Graphical Technique

2024-02-11T22:41:56+07:00

New engineers in mechanical design occasionally encounter difficulty when forecasting the fatigue life of created parts under dynamic conditions. This is because, during the design phase, the size of the pieces is regularly adjusted along with the changing material type, the modified design factor, and even the magnitude of the load in order to generate a prototype that is most compatible with the design circumstances. However, theoretically estimating a part's fatigue life is challenging and time-consuming. Therefore, It might not be the ideal option for the current mechanical design process because it contradicts the QCD paradigm, which is thought to be the cornerstone of industrial production. As a result, this article presents a graphical technique using AutoCAD software to estimate the fatigue life of test specimens made of ferrous metals with ultimate tensile strengths ranging from 490 to 1400 MPa. This approach produces accurate and reliable results when compared to an equation-based fatigue life estimation procedure. This method shortens the time and expense of design. Additionally, as compared to the conventional way, increases the mechanical design's flexibility and agility.

Design Procedure of an Axial Flow Irrigation Pump

2024-03-03T22:33:43+07:00

The paper presents the design procedure of an axial flow irrigation pump. It was designed to deliver a flow rate of 9,000 L/min with a head of 4 m at the Best Efficiency Performance point (BEP). The target hydraulic efficiency was 75%. It started with the preliminary design which predefined the inlet and outlet blade angle of the impeller and the stator vane using a triangular velocity diagram. After that, the other components in the pump system which are the inlet bell, duct, and trailing cone were constructed in the Computer Aided-Design (CAD) software. Then, the flow structure of the pump system was obtained using Computational Fluid Dynamics (CFD). The impeller blade channel, guide vane profile, and the flow channel throughout the pump system were improved to attain target efficiency. This was done by awareness of the development of high velocity (jet flow) and low velocity wake (wake flow) along the entire flow channel. The blade profile was adjusted to minimize wake region while the high jet velocity was reduced. By continuously improving the blade profile, the final version’s hydraulic efficiency was 75.27%. The head was 5.68 m with the flow rate of 11,676 L/min.

Experimental Investigation of the Effects of a Reduced Exhaust Gas Re-circulation Rate on the Performance and Emissions of CI Engines Running on Biodiesel made from Dairy Waste Scum Oil

2024-03-21T22:12:12+07:00

Biodiesel resembles the qualities of fossil diesel while it is also proven to be a greener fuel and viable alternative. However, the primary challenge of using biodiesel was higher emissions of Nitrogen oxides (NOx). Hence to minimize the NOx, an exhaust gas re-circulation (EGR) system could be utilized and could resolve the challenges associated with this higher NOx emissions. In this study, dairy waste scum oil biodiesel was prepared and blended with diesel at 20% by volume (B20) and three different EGR percentages 5%, 10%, and 15%, were investigated on the characteristics of CI engine. Based on the test outcomes, a drop in NOx has been observed with a 15% rate of EGR which is 6.1% lower than conventional diesel. Moreover, brake thermal efficiency increased by 11% as compared to diesel. However, a slight increase in other exhaust emissions was noticed with EGR. The findings indicate that utilizing a lower rate of exhaust gas re-circulation (EGR) at 15 % in conjunction with a B20 blend of dairy waste scum oil biodiesel yields optimal engine performance while minimizing NOx emissions.

Investigation on Yield of Natural Rubber to Bio-Crude Oil from Hydrothermal Liquefaction Process

2024-01-14T22:13:26+07:00

Hydrothermal liquefaction (HTL) requires the presence of water and potentially some catalyst to convert biomass straight to bio-crude oil. In this study, the raw natural rubber is converted to bio-crude oil by the hydrothermal liquefaction process. Experiments are conducted in the autoclave reactor sized of 100 mL at various temperatures ranged between 325-400 °C, with water to natural rubber mass ratios of 1:1 to 5:1, and reacting times of 30-75 minutes. From the investigation, it was found that the highest bio-crude oil yield of 71.4 wt% can be obtained at temperatures of 350 °C, water to natural rubber mass ratios of 4:1, and reacting time of 60 minutes. From the Fourier transform infrared spectroscopy analysis, the major components of the bio-crude oil compound contain high carbon and hydrogen contents which are similar to fossil crude oil in generals. Therefore, it is suggested the synthesis of liquid fuel by the liquefaction process of natural rubber in Thailand is feasible and could be one of the energy potential in the near future.

Transient Heat Transfer in 2D Air Jet Impingement on High-Temperature Plate

2024-03-20T22:01:28+07:00

This study explores the transient heat transfer characteristics of two-dimensional air-jet impingement on a heated surface. Utilizing numerical methods, the research comprehensively analyzes thermal behavior and transient heat transfer mechanisms, considering varied jet parameters, plate temperatures, and time. The investigation covers Reynolds numbers (Re) in the range of 3000 to 12000, based on the hydraulic diameter, with nozzle diameters (Dj) of 3mm, 4mm, and 5mm. The nozzle jet-to-plate distance (H/D) is varied from 0.2 to 2. Results reveal substantial variations in Nusselt numbers (Nu) corresponding to changes in Re and jet-to-plate distance. In addition, approximately Re 12000 the largest friction factor occur at 3mm jet diameter. The Notably, heat transfer near the stagnation point intensifies with decreased jet-to-plate distance, while heat transfer near the boundary point diminishes. These findings offer valuable insights for practical applications in thermal management and heat exchanger design.

Force Feedback Control System for a Virtual Tank Driving Simulator

2024-04-08T21:54:43+07:00

The virtual force feedback system has not been implemented in most tank driving simulators which provide less realistic and less effectiveness of army personnel training. M60A3 tanks have been a prevalent tank for many decades but the information of military tanks was mystery, and has rarely been presented or published. Force exerted by a driver to the driving mechanism of a tank vehicle could be varied due to model uncertainty. The dynamics of a mechanical mechanism, which combines the rotational motion, static friction, sliding friction, and fluid friction, is considered. This paper presented the systematic technique to collect the force information and design force feedback system for a virtual tank driving simulator. Force measurements were applied for collecting the force exerted by drivers on the gas pedal, the brake pedal, and the handlebar of the tank. The force data is the reference data for designing the virtual tank driving simulator. The tank's driving mechanisms with force feedback systems, those are a brake pedal, a gas pedal and a handlebar, were developed. The force sensors were used as feedback signals to control industrial servo motors to generate resistance forces as the original M60A3 tank. Vehicle dynamic model was implemented to the virtual driving simulator as vehicle system integration as Hardware-in-the-loop (HIL). The force feedback control system generated the maximum force as 214.06 N. and 466.78 N. on gas pedal, and brake pedal, respectively as the actual M60A3 tank which the errors are less than 3%.

Development of a Simple, Low-Cost Electric Propulsion System for Electrifying Long-tail Canal Boats: A Case Study in Bangmod Canel, Bangkok

2024-04-17T22:07:01+07:00

This study aims to convert a long-tail boat's propulsion system from an internal combustion engine to an electric motor for enhanced sustainability and reduced environmental impact. The 5-meter boat underwent design modifications, incorporating an electric hub motor connected to the propeller via a power transmission system. Tests conducted in Bangmod Canal, Bangkok, compared the electric and engine-powered boats in terms of energy consumption and noise levels. Results indicated that the electric boat, despite a slightly lower speed, exhibited advantages in energy efficiency and noise reduction. Economic analysis projected a return on investment within 2 years and 8 months, with a notable Internal Rate of Return (IRR) of 26.20%. The electric conversion proved economically superior, offering cost savings, improved quality of life for residents, and mitigation of pollution along the canal.

Numerical Investigation of the Variations in Velocity and Pressure due to Various Building Design with Pedestrian Wind

2024-04-23T20:29:49+07:00

The numerical investigation of the effect of the shape of a high-rise building on pedestrian winds has been done. The study investigates the influence of building shapes on pedestrian-level wind comfort using an Ansys workbench and a virtual fluid domain of 600m×480m×800m. Square, rectangular, circular, hexagonal, and octagonal-shaped buildings have dimensions of (40m×40m×60m), (50m×40m×60m), (40m×60m) (D×H), (20m each side), and (15m each side), respectively. The variations in the shape of different buildings have a constant channel width of 12m. The results were compared to CFD models for the exact different house module using different velocities of wind with Large eddy simulation (LES) model. The study found that increasing the sides of buildings shows favourable pedestrian wind level characteristics. Circular shape offers a comfortable pedestrian level with their small channel space and low separation zone, setting them apart from other shapes like square, rectangular, hexagonal, and octagonal buildings. As a result of having the same width, square-shaped buildings have comparable pedestrian wind velocity in case -1 (C5 – C6 = 12 meters). This is because of the venturi effect, which causes wind speeds to be at their lowest at high space locations. The width of high-rise structures increases. There are a number of factors that influence wind levels in various forms, including wind direction, turbulence, and channel flow. While square and rectangular structures have a significant wind separation, circular buildings provide better walking conditions than their square and rectangular counterparts.

Towards Inclusive Transportation: Smart Steps for Elderly Commuters in the Public Transport Buses

2024-06-11T20:57:05+07:00

This paper addresses a significant issue prevalent among elderly populations worldwide: the fundamental accessibility of public transportation. This accessibility remains a cause for concern since many countries primarily procure buses designed to serve the younger demographic, with limited consideration for the elderly. One prominent challenge arises from the elevated floor height of these buses, resulting in high steps and multiple stairs, rendering boarding nearly impossible for elderly and disabled individuals. In such cases, boarding often necessitates assistance from another person. These factors not only impede the personal and social development of elderly individuals but also restrict their participation in society. To tackle this issue, the authors have undertaken the task of designing and developing a functional prototype that can be retrofitted onto buses to ensure safe travel for the elderly. The system's initial creation involved the use of 3D modelling software, followed by a comprehensive structural stability analysis conducted through the ANSYS Workbench. Subsequently, the authors fabricated the physical prototype. It is worth noting that the system operates efficiently, reducing boarding and deboarding times to about one minute each during the laboratory trials.

Comparative Performance of Meta-Heuristic Algorithms for Low-Speed Wind Turbine Blade Structural Optimization

2024-07-08T21:41:28+07:00

The comparative assessment of recent Metaheuristics (MHs) optimization techniques was conducted within the context of low-speed wind turbine (LS-WT) blade design, with a focus on simultaneously addressing aerodynamic and structural considerations. The study encompasses two LS-WT design problems: the first aims to minimize wind turbine (WT) mass, while the second employs a weighted sum technique to simultaneously minimize WT mass and maximize turbine power. A comparative study on the performance of several recent MHs on the LS-WT problems has been conducted. The optimal design of the WT in the second problem exhibits greater dimensions compared to the shape in the first problem. The WT mass in the second problem is approximately 21 percent higher than in the first problem, reflecting the higher power output achieved in the second problem is more than 5.7 percent compared to the first problem. Statistical analysis of fitness values revealed that L-SHADE exhibited superior performance in terms of both average fitness and standard deviation compared to other algorithms.

Fatigue Life and Modal Analysis of Centrifugal Fan's Impeller in Portable Pneumatic Extinguisher for Forest Fires

2024-08-13T19:55:02+07:00

The centrifugal fan used in a Portable Pneumatic Extinguisher (PPE) designed for forest fires is a high-speed rotating machine that is vulnerable to vibrations, which can ultimately lead to system failure. Therefore, fatigue and modal analysis of the fan are crucial in the design and development process to prevent premature failure. Previous work optimized the PPE impeller design with the inner blade angle set to 64°, the outlet blade angle to 120°, and the number of blades to 24. However, fatigue analysis and modal analysis were not considered. Thus, this study examined the fatigue life and modal behavior of the impeller in a centrifugal fan used in a PPE, utilizing the Finite Element Analysis (FEA) method. The results showed that the impeller experienced a maximum von Mises stress of 26.4 MPa, with a maximum deformation of 3.07 × 10⁻⁴ mm in the section with the highest stress. The minimum deformation was 1.52 × 10⁻⁶ mm, and the maximum displacement recorded was 0.056 mm. Fatigue life analysis indicated minimal or no visible damage to the impeller. Modal analysis revealed that the lowest frequency was 150.8 Hz, approximately 22.6% lower than the natural frequency, suggesting that resonance is unlikely under normal operating conditions. Overall, the impeller design demonstrated sufficient structural integrity and fatigue life for the PPE's intended use in forest fire applications.

Parametric Optimization for Dimensional Accuracy and Surface Roughness in Additive Manufactured Novel Acetabular Liner using Two Different Techniques

2024-09-09T20:56:52+07:00

Fused Filament Fabrication (FFF), also known as Fused Deposition Modeling (FDM), is a widely utilized additive manufacturing technique. By fine-tuning process parameters, improvements in product quality can be achieved. This study investigates optimizing parameters: print speed, layer height, and infill density in fabricating acetabular liners, a component of hip implants using FFF. Four decision-making methods namely the Analytic Hierarchy Process (AHP) combined with Technique for Order of Preference by Similarity to Ideal Solution (AHP-TOPSIS), Entropy Weight Method (EWM)-TOPSIS, AHP-Multi-Objective Optimization on the basis of Ratio Analysis (MOORA), and EWM-MOORA) are compared to identify the most suitable parameter settings. Observations from Experiments are used in each method. The research evaluates these methods to determine the optimal FFF parameters and the results will help to improve the 3D Printing process through informed parameter selection.

Experimental Investigation on A356.1 Aluminum Composite Reinforced with Zirconia Nano Metal Matrix Composites Fabricated via Stir Casting Technique

2024-09-08T12:45:28+07:00

Aluminum amalgams are used in self-impelled productions because of their longevity strength and mechanical behavior, alloys of aluminum have numerous interests while used in engineering determinations, in spite of their better formability and malleability, low density, high electrical and thermal comductivity. In this work, ZrO₂ Nanoparticles with particle size of 50nm reinforced A356.1 aluminum alloy, Nano Metal Matrix Composite were prepared through liquid state casting i.e. stir casting method with varying weight proportion ratios of 1.0, 2.0, 3.0, and 4.0% at a constant speed of 100rpm for 30 minutes. Fabricated Nano Aluminum metal were characterized using Powder X-ray Diffraction (PXRD), Energy Dispersive X-ray Analysis (EDX) and Scanning Electron Microscope (SEM) which showed their distribution of surface structure, crystalline phase and elemental compositions. Hardness tests were carried on Brinell hardness, tensile tests were carried on electronic tensometer and also tribological behavior of fabricated material was conducted by computerized pin on disc wear testing apparatus. As the reinforcement wt. % percentage increases, more load is transferred to these strong reinforcing elements, resulting in higher hardness and tensile strength for the composite. Results revealed that the NMMCs with 4.0 % reinforcement exhibit superior mechanical and tribological properties.

Influence of Inserted Different Ribs Configuration in 2D Horizontal Channel on Characteristics Turbulent Fluid Flow and Forced Heat Transfer: A Numerical Investigation

2024-10-03T21:29:01+07:00

The current study deals with the analysis of a two-dimensional (2D) single-phase turbulent airflow in a channel having ribs of different configurations. COMSOL Multiphysics software was used to investigate all cases that were carried out numerically using the standard k-ε model. Several parameters were studied as a variable function against the Reynolds number in ranges (9000 to 18000), including the rate of heat transfer, friction factor, and pressure difference of all rib shapes compared to the empty channel. The shape plays an important role in the characteristics of fluid flow and heat transfer distribution and the circular rib shows better heat transfer performance and friction factor compared to the normal channel and other designs, therefore, the circular design ensures improved thermal-hydraulic performance. Also, the percentage of increase in the heat transfer rate represented by Nusselt number (71.48, 69.99, and 67.29%) for rib designs (quarter circle, square, and triangle) respectively compared to the channel without ribs. As the Reynolds number rises, the pressure drop across the fluid entry-exit zone of the channel is influenced by the ribs being inserted inside as well as when the channel is empty.