Journal of Research and Applications in Mechanical Engineering

Development of An Electric Power Generator Using Hydrogen

2024-12-16T20:53:37+07:00

Hydrogen is the best form of energy for achieving carbon neutrality, it is also known as the ultimate energy in the new century. H₂ internal combustion engines have significant advantages of zero-carbon, high efficiency, and high reliability, making them one of the uppermost directions for hydrogen energy applications. In the research, we try to develop a hydrogen (H₂) electric power generator and an on-site H₂ generation system based on chemical reaction. In the experiment, firstly, a H_2-based electric generator and H₂ on-site generation system were established. Secondly the performance of the above H₂-based electric power generation system was tested. Finally, since extra heat was generated during the process of on-site hydrogen generation, then heat generated during H₂ on-site generation was recovered through cooling water for reuse. It was found that the maximum output of the generator was 470W under the condition of H₂generation flow rate of 25L/min and the thermal efficiency was 10.46%. Besides, it was confirmed that at the cooling section, within 10 minutes, the temperature change was up to 8 °C for the cooling water of 10L under the condition of hydrogen generation rate of 30L/min and the heat recovery efficiency was up to 50%.

Clamping Force Optimization for Four-Jaw Lathe Chuck Operators

2025-01-12T18:57:21+07:00

The manufacturing industry faces critical challenges related to shortages of skilled technicians and declining skill levels, compounded by a lack of instructors and limited training time. Effective skill transfer and the development of new skilled operators are essential. In lathe operations, proper clamping of workpieces is crucial for safety and machining accuracy. However, in the absence of clear standards for clamping force, reliance on instructors’ experience is common. This study addressed this issue by developing a clamping force monitoring device for a four-jaw lathe chuck, incorporating theoretical calculations and experimental verification of the required clamping force. Additionally, it investigated the clamping force applied by instructors and quantified the operator’s clamping force using a safety factor. For rough cutting, the safety factor was 1.7 times the reference instructor’s force, and for finish cutting, it was 2.1 times. The optimal clamping force was determined by adjusting the required force with a safety factor and half the observed variation width, resulting in 15.1 kN for rough cutting and 4.7 kN for finish cutting. The study concluded that the clamping force monitoring device optimizes clamping for safe and accurate machining, establishing a clear standard for beginners.

Enhancement of Vickers hardness and Electrical Conductivity in 3YSZ-8YSZ Oxide System with Al₂O₃ Addition

2025-01-08T20:38:31+07:00

Solid oxide fuel cells (SOFC), primarily composed of oxide materials, operate at temperatures ranging from 600 to 1000°C. Yttria-stabilized zirconia (YSZ) has high oxide ion conductivity at 900℃, making it a promising material for SOFC electrolytes and anode electrodes. In this study, Al₂O₃ was added to 3YSZ-8YSZ oxides, and the electrical conductivity and Vickers hardness were evaluated. Recommended values for the amounts of 3YSZ, 8YSZ, Al₂O_3, and sintering temperature were obtained by machine learning. The recommended value determined from the electrical conductivity, Vickers hardness, and sintering temperature of C0(50.0wt% 3Y-50.0wt% 8Y-0wt% Al₂O₃), C05(49.7wt% 3Y-49.7wt% 8Y-0.50wt% Al₂O₃), and C1(49.5wt% 3Y-49.5wt% 8Y-1.0wt% Al₂O₃), and other related samples. The recommended composition was determined to be R1 (48.8wt% 3Y-50.8wt% 8Y-0.35wt% Al₂O₃), and the sintering temperature was 1410°C. The crystal structure of R1 was cubic structure indexed as ICDD PDF # 00-030-1468. The electrical conductivity of R1 was observed to be more than 1000 times higher than that of sample C0 without alumina added.

Enhancing Split-Type Air Conditioning System Efficiency through CLOHP Integration

2025-01-31T17:34:52+07:00

This study investigates the impact of integrating looped oscillating thermosyphon heat pipes (CLOHPs) in a 3.52 kW (12,000 BTU/hr) split-type air conditioning system. The CLOHP uses water as the working fluid and R-134a for sensible heat exchange, with the goal of reducing refrigerant temperature before reaching the capillary tube, improving system efficiency. Performance tests were conducted at ambient temperatures of 294.2K, 296.2K, 298.2K and 300.2K. Results showed up to a 15.84% improvement in evaporation rate (Qevap), 16.37% in coefficient of performance (COP), and 16.13% in energy recovery rate (ERR), with higher effectiveness at higher temperatures. These findings demonstrate the potential of CLOHPs in enhancing energy efficiency and thermal performance in air conditioning systems, offering a promising solution for energy savings in residential and commercial applications.

Research on Performances of Rotor Dehumidification for Ring Main Unit

2024-12-26T22:18:49+07:00

In view of the dehumidification problem of ring main unit, a dehumidification scheme using a small dehumidification rotor is proposed. A small dehumidification rotor device impregnated with polymer adsorbent was designed and manufactured. The experimental device adopts thermal balance calibration, and the error range is less than 3%. In order to further study the performances of the small dehumidifying rotor, the small dehumidifying rotor was tested by changing the regeneration temperature and speed under two air conditions of high temperature and high humidity and low temperature and high humidity. The test results show that it has good dehumidification effect under the two different environmental conditions. After a long time of on-site dehumidification test of the ring main unit, even if the relative humidity outside the ring main unit reaches more than 80%, the relative humidity inside the ring main unit remains below 65%, effectively solving the problem of condensation in the main unit.

Numerical Analysis of Confinement Phenomenon with Reflected Shock Waves by Opposing Wall

2025-01-12T18:55:32+07:00

We propose the shock wave confinement phenomenon as a new method for generating high-energy fields using shock waves. This study investigates the conditions for the shock wave reflection in a supersonic jets, essential for the shock wave confinement phenomenon. The parameters of this study are the pressure ratios of the high and the low-pressure chamber of the shock tube, which are 10.7, 22.6, 35.0 and 46.0, respectively. The results show that the increased pressure ratio causes the shock wave to be reflected in the jet. The non-dimensionalized thicknesses of the low acoustic impedance near the collision between the shock wave and the jet in the acoustic impedance considering the flow velocity are 1.5, 0.9, 0.6 and 0.2 when the pressure in the shock tube varies to 10.7, 22.6, 35.0 and 46.0 respectively. The thicknesses with low acoustic impedance show similar trends in the presence or absence of shock wave reflection. Therefore, the acoustic impedance, considering the flow velocity, can qualitatively explain the reflection of the shock wave to the jet.

Effect Triangular Baffles on Thermal- Hydraulic Optimization and Turbulent Flow CuO/ Water Nanofluid in 2D Channel Using Computational Fluid Dynamics Method

2025-02-15T22:13:13+07:00

In large-scale applications, fluid flow with baffles is a multifaceted phenomenon because it plays an important role in improving heat transfer and mixing in addition to other fluid dynamics processes. To achieve the required heat transfer, the design of triangular baffle models inside the channel is of great importance. In the present work, the effect of the inclusion of baffles in the upper and lower surface of a two-dimensional channel of a nanofluid flow (CuO+Water) with volumetric fractions (5%) steady-state single-phase turbulence with Reynolds number ranges of (7000-17000) is numerically studied. The channel is divided into three main sections, the first and the last are thermally insulated, and the second is subjected to a constant uniform heat flux of (30 kW/m²). Using the finite volume method of the Ansys Fluent program, all the equations governing the fluid flow inside the channel, including the conservation of mass, momentum, and heat energy, were solved using the turbulent k-ε for high Reynolds values. The numerical results of the current study indicated that the heat transfer rate gradually increases with an increase in the Reynolds number, while the friction factor gradually decreases with an increase in the Reynolds number, moreover, the values of the Nusselt number and the friction factor were affected by the height of the baffles, where the increase in height both increases gradually, it was also found that the height of (12 mm) gave the highest percentage of heat transfer enhancement with a value of (82.69%) compared to the other heights (2, 4, 6, 8 and 10 mm), which gave a ratio of (60.46, 70.01 and 80.65%), respectively. Finally, the pressure, temperature and velocity distribution of the nanofluid differed when the baffles were placed to disturb the passing flow compared to the normal empty channel.

Performance Estimation of Air Conditioner Using Water Cooled Condenser

2025-01-22T22:33:36+07:00

The objective of this research paper is to study the effect of using water for condenser cooling on the performance of an air conditioner. A condenser is immersed in a tank in which water is circulated through it. The air conditioner based on vapour compression refrigeration system is experimented with for different percentages of condenser immersion in a water tank. The result obtained is compared with that of a conventional air conditioner, which indicates that there is a rise in heat transfer of the condenser with an increase in water flow rate. The water cooled condenser exhibits better performance than the conventional air-cooled condenser. An increase in coefficient of performance of 11.6% is obtained when the three-fourth condenser is dipped in a water tank with a flow rate of 400 liter per hr.

Experimental insights into heat transfer mechanisms in a turbulent channel flow with inclined V-shaped baffles

2025-02-01T19:58:42+07:00

This study conducts an experimental analysis of heat transfer and pressure drop in a solar air preheater channel with an aspect ratio (AR) of 3.75:1, featuring inclined V-shaped baffles (I-VB) on one wall under continuous heat flux circumstances. The study focuses on the effects of the inclined angles on the heat transfer coefficient (h), pressure drop (DP) and thermal-hydraulic performance (THP). The inclined angles (q) explored include 0°, 45° and 90°, with attack angles (a) set at 45°, and Reynolds numbers (Re) varying from 6000 to 24,000. The experimental results show that the inclined angles significantly affect the temperature distribution, Nusselt number distribution, friction factor, and thermal-hydraulic performance. The heat transfer rates in channels with inclined V-shaped baffles (I-VB) at inclined angles of 0°, 45° and 90° are 13.95-53.46%, 165.29-361.08%, and 175.91-378.34% higher than those in a smooth channel, respectively. However, the corresponding pressure losses increase by 2.01-2.87, 10.42-13.37, and 15.03-19.91 times for these inclined angles. At all Reynolds numbers, the inclined V-shaped baffles with an inclined angle (θ) of 45° demonstrate superior thermal-hydraulic performance, reaching a peak value of 1.94 at a lower Reynolds number of 6000.

Impact of Biaxial Loading on the Buckling Delamination Mode of the Pzt+Metal+Pzt Sandwich Rectangular Thick Plate With Embedded Interface Cracks

2025-02-16T22:23:29+07:00

This research investigates the buckling delamination mode of embedded interface cracks in a PZT+Metal+PZT sandwich plate, utilizing the piecewise homogenous body model and the three-dimensional linearized theory of stability loss for piezoelectric materials. An interface rectangular crack is presumed to exist between the layers of the face and the core, with the plate subjected to bi-axial uniformly distributed compressive forces acting on the vertical sides of the rectangular sandwich plate. The surfaces of the analyzed interface cracks are presumed to possess negligible initial defects prior to loading, and the progression of these initial imperfections under bi-axial compressive forces is examined. Based on the initial imperfection criterion, the critical buckling pressures for local delamination caused by buckling of the rectangular plate around cracks are determined [1]. When the loading levels are beneath the critical threshold, the crack edges display surface wrinkles. This study seeks to examine and evaluate surface wrinkles about diverse geometric and material aspects.

A Comprehensive Analysis of Mechanical Metamaterial Types and Applications Along with Challenges and Current Emerging Trends in Research

2025-02-09T10:09:23+07:00

Mechanical metamaterials are a type of engineered materials that have micro and nano-scale structures, which are specifically designed to exhibit properties that are not typically found in natural or conventional materials. Unlike conventional materials, which have properties determined by the characteristics of the material itself, mechanical metamaterials obtain their mechanical behaviors from the specific organization of their substructures also known as unit cells. This study aims to provide a brief review of the mechanical properties of the mechanical metamaterials used for various industrial, medical, and robotic applications. Further, different types of mechanical metamaterials, such as lattice-based, topological, gradient, architected, Origami and Kirigami-inspired metamaterials, have been presented along with their applications in the field of soft robotics. Additionally, emerging trends and future directions point towards the development of more responsive, intelligent and sustainable mechanical metamaterials in the future.

Numerical Analysis to Study Thermal Performance of Single Pipe Heat Exchanger Using Combined Technique of Nanofluid and Baffles

2025-03-18T17:33:03+07:00

To enhance the performance of the thermal system, nanomaterials added with the basic working fluid have gained great attention in recent years as one of the practical solutions. However, to further improve the overall efficiency, common techniques were used, for example, fins and baffles or twisted tape with a nanofluid. The current study involves numerical simulation using the (Ansys Fluent) program to optimize the heat transfer rate and turbulent flow characteristics in a two-dimensional circular tube of a heat exchanger. Common optimization techniques were used, first, the inclusion of baffles with a square configuration along the axis of the fluid flow, and second, the addition of different nanomaterials (Al₂O₃ and CuO) with the basic working fluid with variable volume fractions (0.2 -1.2%). The surface of the upper and lower tubes is exposed to a uniform constant heat flux of (80 kW/m²). The effect of Reynolds numbers within the ranges (6000-30000) on the thermal characteristics of the heat exchanger tube has been studied numerically. The numerical results found that the heat transfer coefficient gradually increases with increasing Reynolds number ranges, hence the gradual increase in the Nusselt number. Moreover, compared to a smooth tube, the amount of Nusselt number increases using baffles and nanomaterial, where the ratio of the increase to the heat transfer rate when baffles are inserted is (80.82%), but when using nanomaterials (Al₂O₃ and CuO), respectively, is (83.64 and 82.501). The volume fraction ratios of the nanomaterials improved by the improvement compared to the first material (0, 0.2, 0.7 and 1.2%) appeared (80.82, 83.64, 84.124 and 84.63%) respectively. Finally, the friction factor is affected by the velocity of the fluid, which gradually decreases as the Reynolds number ranges increase.

Enhancement of Used Temple Oil Biofuel Blends Using Artificial Intelligence for Eco-Friendly Cities Medium Duty Commercial Vehicles in India

2025-03-14T14:01:01+07:00

The efficiency of bio-blends made from seeds for medium-duty urban commercial vehicles is the subject of a study whose results are presented in this article. The analysis took into account a number of variables, such as engine specifications, economic consequences, and production capacity. An artificial intelligence algorithm was trained to predict emission characteristics, combustion, and performance using experimental data. The findings showed that while brake-specific fuel consumption (BSFC) increased at full load, brake thermal efficiency (BTE) dropped for both diesel and bio-fuel combinations as engine speed increased. In particular, there was an 11.9% increase in BSFC when diesel was used instead of mixtures of biofuel and diesel. The bio fuel-diesel blends also reduced maximum cylinder pressure and NOx emissions, with maximum reductions of 9.8% and 22.2% at specific RPMs, respectively. Additionally, these blends significantly decreased emissions of carbon dioxide (CO₂) and smoke. Overall, biofuel blends provide substantial benefits by reducing exhaust pollutants and improving engine efficiency.

Microstructural and Mechanical Evaluation of Dissimilar AISI 304 and 430 Stainless Steel Welds Created with GMAW and ER308L Filler Metal

2025-04-09T23:18:22+07:00

The fusion of dissimilar materials—specifically AISI 430 Ferritic Stainless Steel (FSS) and AISI 304 Austenitic Stainless Steel (ASS)—was accomplished using the Gas Metal Arc Welding (GMAW) process, with ER308L serving as the filler material. The experimental design was based on the Taguchi approach, which used L27 Orthogonal Arrays to systematically alter welding parameters. The impact of these factors was assessed using Analysis of Variance (ANOVA). Mechanical properties such as tensile strength, hardness, and penetration depth were evaluated, revealing that the ultimate tensile strength reached 630.7 MPa of the welded samples. The hardness of weld zone peaked at 310 HV, exceeding the base metals due to martensitic transformation and grain refinement. Optimal welding parameters were determined at 190 A, 32 V and 40 cm/min. Microstructural investigations were conducted using Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray Spectroscopy (EDX), X-ray Diffraction (XRD), and Optical Microscopy. XRD presented dominant martensitic peaks at 44.88°, 65.34°, 82.06° and 99.52°, corresponding to (110), (200), (211) and (220) crystallographic planes. EDS revealed the phase transformation was significantly influenced by the diffusion of Cr (19.20 %), Ni (6.31 %) and C (4.52 %). The findings indicated the weld bead's shape as well as the consequences of microstructural changes. Constant current and voltage, faster welding rates resulted in increased penetration depth, and the weld zone was harder than both the base metal and the HAZ.

Classification of Regular Microreliefs of the Volumetric Class

2025-03-17T00:23:51+07:00

An analysis of the geometric features and functional purposes of different classes of regular microreliefs has been conducted. Some optimal geometric parameters for the grooves of regular microreliefs (cross-sectional and longitudinal shapes and sizes) have been determined to ensure optimal surface performance in friction pairs and facilitate relative reciprocating motion. A new classification of regular microrelief, called the volumetric class microrelief, has been presented. The groove of this microrelief and its constituent elements have been considered a basis for forming multiple microrelief options with different geometric parameters, constituent elements, and their mutual arrangement within the groove and within the microrelief. This approach will enable the creation of volumetric microreliefs, both regular and partially regular, with different functional purposes. Depending on the geometric features, these types of relief can be applied to surface elements subject to non-uniform wear at the locations of most significant dynamic loads (connecting rod liners, cylinder liner surfaces of internal combustion engines, etc.). The optimal shape of the cross-section of the microrelief grooves of the volumetric class is established under the condition of the maximum value of the residual groove area when the surface is worn by 50% of the groove depth. For a rectangular cross-sectional profile, the residual groove area relative to the initial one is 81%; for a triangular one, 50%; and for a semicircular one, 69%. The groove shape of the micro-relief has been justified using an analytical method. The main features of the classification of volumetric class microreliefs have been identified, dividing them into two groups: the first one, describing the specific geometry of the microrelief grooves, and the second one, describing the particular features of the mutual arrangement of these grooves, creating a unique pattern of microrelief on the surface.