Journal of Mechanical Engineering and Sciences

Advancements, challenges, and implications for navigating the autonomous vehicle revolution

Md Naeem Hossain — 2024-06-28

The deployment of self-driving cars has significantly impacted society, offering several benefits such as better passenger safety, convenience, reduced fuel consumption, minimised traffic congestion and accidents, cost savings, and improved reliability. With the development of automated driving systems, autonomous vehicle technology has progressed from human-operated vehicles to conditional automation, utilising an array of sensors to constantly observe their surroundings for potential hazards. However, it is crucial to highlight that full autonomy has not yet been reached, and there are several problems involved with this revolutionary technology. This article explores the advancements, challenges, and implications inherent in the widespread adoption of autonomous vehicles. Recent advancements in sensor technology (cameras, RADARs, LiDARs, and ultrasonic sensors), artificial intelligence, the Internet of Things, and blockchain are just some of the topics covered in this article regarding autonomous vehicle development. These advancements are critical to evolving and incorporating autonomous vehicles into the transportation ecosystem. Furthermore, the analysis emphasises the considerable problems that must be overcome before self-driving cars can be widely adopted. These difficulties include security, safety, design, performance, and accuracy. Focused solutions such as increasing cybersecurity protections, refining safety standards, optimising vehicle design, enhancing performance capabilities, and assuring correct perception and decision-making are proposed to tackle these challenges. Lastly, autonomous cars have great promise for transforming transportation systems and improving a wide range of areas of our lives. Nevertheless, successful implementation requires overcoming existing difficulties and pushing technological innovation’s limits. By solving these problems and capitalising on artificial intelligence, the Internet of Things, and blockchain breakthroughs, we can navigate the autonomous car revolution and realise its full potential for a safer, more efficient, and sustainable future.

Computational fluid dynamics-based study on the heavy crude oil-water emulsion flow through sudden expansion, contraction and 90° bend

Arun Jana — 2024-06-28

Oil-in-water emulsion (O/W) can be prepared to transport heavy crude oil (HCO) through a pipeline effectively with reduced viscosity and pumping power. Various pipe fittings such as bend, elbow, sudden contraction, sudden expansion of pipe etc., are sometimes essential in the design of such pipelines. Energy losses take place due to skin and form friction during pipe flow. The determination of friction loss, which results in pressure losses, in pipes and fittings is crucial for the proper estimation of pumping power required for pipeline transport of the emulsions. The present study represents a numerical simulation of the emulsion flow through sudden expansion, contraction and 90° bend in the pipeline using a mixture model considering the prepared emulsion as a pseudo-homogeneous liquid. O/W emulsion was prepared at the optimum conditions of viscosity and stability with 25 %v/v water, 75 %v/v HCO and 4.5 % w/vsurfactant PS-81. The effect of parameters like average mixture velocity on pressure drop and pressure loss coefficient for various pipe fittings has been studied as laminar flow using ANSYS Fluent 2019 R3. The estimated value of the loss coefficient for the expansion, Ke, is 0.2313, and the loss coefficient for the contraction, K_c, is 3. Higher values of loss coefficient for contraction are due to higher pressure drop. For a 90° bend, as the average mixture velocity, and hence Reynolds number, increases, the pressure loss coefficient decreases. Within the range of velocity considered in the present study, an increase in pressure drop has been observed for sudden contraction, whereas a slight rise in pressure drop was found for sudden expansion. A nearly linear increase in pressure drop has been observed for a 90° bend. Pressure loss data caused by such pipe fittings are helpful in predicting additional pressure drops caused by them and, hence, an increase in pumping cost.

The behaviour of ternary hybrid nanofluid: Graphene oxide, Aluminium oxide, Silicon dioxide in heat transfer rate

F. M. Hanapiah — 2024-06-28

The miniaturization in the design of the electronic system became inevitable due to the rapid advancement and development of technology. This has imposed challenges to the thermal management capability as the heat flux density has increased tremendously due to a smaller heat transfer surface. Nanofluids adoption in electronic cooling seems to be an alternative way for better heat dissipation. This research explores the feasibility of ternary hybrid nanofluids GO: Al₂O₃: SiO₂ in water with different volume concentrations and mixture ratios in a serpentine cooling plate. In this research, 0.01% GO + Al₂O₃: SiO₂, 0.006% GO + Al₂O₃: SiO₂, and 0.008% GO + Al₂O₃: SiO₂ in mixture ratios of 10:90 and 20:80 (Al₂O₃: SiO₂) were studied. The result showed that 0.01% GO + Al₂O₃: SiO₂ (10:90) nanofluids displayed the highest enhancement of heat transfer coefficient with 1.1 times higher as compared to the base fluid. This was then followed by 0.008% GO + Al₂O₃: SiO₂ (10:90) and 0.006% GO + Al₂O₃: SiO₂ (10:90) with 1.03 times and 0.87 times higher heat transfer coefficient enhancement consecutively as compared to the base fluid. In term of mixture ratios, GO in 10:90 (Al₂O₃: SiO₂) performed better than 20:80. To assess the feasibility of adoption, the advantage ratio (AR) was conducted to measure both heat transfer enhancement and pressure drop effect. The AR analysis showed that at the lower Reynolds, Re number region, the 0.01% GO + Al₂O₃: SiO₂ (10:90) ternary hybrid nanofluids was proven to be the most feasible due to a higher ratio of heat transfer enhancement over the pressure drop penalty.

Empowering industrial automation labs with IoT: A case study on real-time monitoring and control of induction motors using Siemens PLC and Node-RED

A. H. Embong — 2024-06-28

This initiative discusses the utilization of the Internet of Things (IoT) to enable smart control and monitoring of multiple devices in an industrial automation lab. The traditional manual approach of overseeing device performance in the industrial sector is prone to errors and lacks scalability and efficiency. The investigation compares Node-Red and Labview and proposes a design for remote control and monitoring. The process involves Node-Red, Siemens S7-1200 PLC, Sinamics V20 and an induction motor. Key steps include configuring frequency data exchange between Node-RED and the PLC, allocating frequencies based on an ID communication protocol, and using PLC data to power the induction motor via the Variable Frequency Drive (VFD). An experimental setup aims to validate the system’s applicability and functionality by comparing theoretical data with experimental results. The study included a no-load test to observe motor shaft operation and a variable load setup where the motor was subjected to varying loads. Real-time monitoring of speed and torque adjustments was facilitated by the control unit. The no-load test revealed an average slip of 0.06 for the motor, with a direct voltage-frequency relationship. In the variable load test, the motor maintained a consistent voltage-to-frequency ratio, while current behaviour varied across different load ranges. By leveraging IoT connectivity using Siemens PLC S7-1200, this project demonstrates real-time data collection and analysis using Node-RED, Google Firebase, Google Sheets, and remote-control capabilities, leading to improved operational efficiency, reduced downtime, and increased productivity. The article emphasizes the significance of IoT in industrial automation labs and highlights its potential to revolutionize device control and monitoring, particularly focusing on the analysis of induction motors. The main challenge was to interface the devices to create an interconnected robust system, which was successfully overcome by implementing various IoT protocols. The system generated promising results, confirming IoT’s potential in industrial automation.

Numerical and experimental investigation for swing-up control of an inverted pendulum using Arduino microcontroller

M. M. Donatoni — 2024-06-28

The Inverted Pendulum is a classic control problem, it has non-linear dynamics, is underactuated and naturally unstable. Thus, the development of a system capable of controlling it goes through challenges such as modeling, design requirements and implementation of the control hardware. This work proposes the swing-up of the linear inverted pendulum using energy method with adjustable parameters, followed by its stabilization by an LQR controller. This work demonstrates how the system can be implemented using an Arduino microcontroller for acquisition of state variables and control commands. Furthermore, as a highlight, the implemented algorithm indicates a way to stabilize the sampling frequency, making the derivative process stable in the applied hardware, making control optimized. The applied method was efficient to perform the swing-up, consistent with the simulations and as effective as what is seen in the literature.

Numerical study of thermal and hydrodynamic characteristics of turbulent flow in hybrid corrugated channels with different wave profiles

D. Uysal — 2024-06-28

The geometry of the wave profiles used in corrugated channels affects the flow and thermal characteristics. It is possible to increase thermal and hydraulic performance by simply changing the groove profile’s shape without using any additional energy. Therefore, this numerical study focused on the flow and thermal performance of different groove profiles in hybrid corrugated channels. The study was conducted using the finite volume method (FVM) with the standard k-ε turbulence model. The study consisted of three different hybrid corrugated channel flows created by combining the rectangular groove profile and the circular, trapezoidal, and triangular-shaped groove profiles separately. In addition, the numerical results were compared with the rectangular corrugated duct and the straight duct. The corrugated surfaces were kept constant at T_w = 380 K. Nusselt number, friction factor, and performance factor were calculated for different Reynolds numbers (2000 ≤ Re ≤ 10000). Images of flow and temperature contours were presented to demonstrate the effects of groove profiles. According to the numerical findings, the combination of the rectangular groove profile with other groove profiles significantly improved the heat transfer without any significant increase in pressure drop. The thermal performance was significantly affected by Re and the hybrid groove profiles. The rectangular-circular and rectangular-trapezoidal hybrid corrugated channels showed similar behaviors in terms of hydraulic and thermal attitude. It was determined that heat transfer in rectangular-circular and rectangular-trapezoidal hybrid groove profiles improved 4.38 times compared to straight ducts at Re = 8000 and 1.23 times compared to rectangular corrugated ducts at Re = 2000.

Effect of the Mn and Cr contents on the oxidation and creep resistance at 1100°C of cast cantor–based HEAs

P. Berthod — 2024-06-28

Cast High Entropy Alloys (HEAs) derived from the Cantor’s composition may represent alternative substitutional solutions to the superalloys which are constituted for more than half of the critical elements nickel and cobalt. Recently, MC–alloyed HEAs constituted by a Cantor’s type matrix associated to an efficient interdendritic network of MC carbides, have demonstrated promising creep resistance at elevated temperatures. Regrettably, they also show poor high temperature oxidation resistance. This bad oxidation behavior is possibly due to the deleterious effect of manganese and to a too low content in chromium. New alloys were elaborated and tested in oxidation at 1100°C with thermogravimetry follow–up and metallographic characterisation, and their creep behavior was controlled. With less Mn and more Cr than the original alloys, these new alloys demonstrated significant progress in oxidation resistance. These changes in chemical compositions did not modify their creep resistances which were globally maintained, for the carbide-free alloy as well as for the MC-containing ones. These Mn-decreased and Cr-increased MC-containing alloys can be considered as low-cost alternative to polycrystalline Ni or Co-based superalloys for working in moderate conditions of corrosive fluids and applied mechanical stresses.

Navier-Stokes-ω model with slip and friction boundary conditions at high Reynolds numbers

Ö. Ilhan — 2024-06-28

The no-slip boundary condition is indeed a fundamental concept in fluid dynamics, especially for flows at lower Reynolds numbers where viscous effects dominate. However, inertial effects become more significant at higher Reynolds numbers, and the no-slip condition might not accurately represent the behavior of the fluid near the boundary. In such cases, partial slip or slip boundary conditions become more relevant as they take into account the slip between the fluid and the boundary. This study offers the presentation of numerical experiments for a 2-dimensional channel flow, through a step Navier-Stokes-ω model at high Reynolds numbers. The slip boundary conditions with friction is used in these numerical tests, namely along the step and on the lower and upper walls. The impact of the friction coefficient on the flow characteristics is illustrated. Especially for large Reynolds numbers, the effect of the friction coefficient on the flow region is examined. In the numerical tests, the Crank-Nicolson method is used for time discretization, while the Galerkin finite element method is applied for space discretization. It can be observed that as the coefficient of friction decreased, the eddies are further away from the step and moved towards the outer flow. In addition, the size of the eddies are larger for small coefficients of friction. For
Re = 5000, the reattachment length calculated on a fine mesh at time T = 50 is close to the step. For Re = 10000, the reattachment lengths determined for different friction coefficients on both meshes are very similar, with eddies forming just behind the step. Similarly, for Re = 15000 and β = 0.0001, the reattachment lengths calculated on the fine mesh are farther from the step. Conversely, for other values of β, the reattachment lengths are close to the step. The results are explained according to flow physics.

Numerical analysis of the thermal state of a cylindrical body cooled by an internal fluid flow

V. Yessaulkov — 2024-06-28

Mechanical engineering has its own specifics when it comes to describing the thermal state of cylinders. The heating and cooling of bodies with a cylinder surface as their heat exchange area can be considered an important technical task that requires appropriate mathematical foundation. The purpose of this work is to construct a mathematical description of the thermal state of a thermally massive cylinder cooled by a liquid passing through a coaxially located channel. The study proposed a one-dimensional mathematical model for the numerical study of the thermal state of a thermally massive cylinder cooled by a liquid passing through a coaxially arranged channel inside the body under consideration. The mesoscopic modeling scale is the basis of the mathematical model, which employs the mathematical approach of Markov chains theory. The numerical evaluation of cooling scenarios in the flow and looping mode of the cooling fluid movement is carried out. The operability of the mathematical model was investigated by performing a series of numerical experiments. The numerical experiments with the model have shown the possibility of a qualitatively consistent analysis of possible cooling scenarios and their significant differences. The qualitative reliability of the results allows us to consider the proposed model as a reliable scientific basis for describing more complex cooling systems used, for example, in transport technologies and processes.

Large eddy simulation of passive noise reduction in subsonic jets by using chevrons

K. Tewari — 2024-06-28

Chevrons are widely used passive noise reduction devices that have emerged as an significant breakthrough for aicraft industry in enabling substantial noise reduction without sacrificing thrust. However, the conventional testing of different chevron designs necessitates costly experimental facilities. This challenge can be circumvented through computational validation using CFD. Hence, this study employs a hybrid computational aeroacoustics approach to assess the viability of chevrons as a passive noise reduction technique within free subsonic jets using the commercial CFD software StarCCM+. Two sets of numerical simulations performed with and without chevrons applied at the end of the nozzle were examined. The dynamic Smagorinsky model was utilized to resolve the sub-grid scale stresses in these simulations of turbulent flows, which were run using large eddy simulation at an exit Mach number of 0.75. Using Ffowcs Williams Hawkings acoustic equations and the Fourier transform, the far-field analysis was performed on the acquired flow field to calculate the jet noise distribution in terms of the Sound Pressure Levels (SPL). The simulation results for free jets show good agreement with the published experimental data in terms of capturing the mean flow field and the acoustic levels in farfield. The simulations with chevrons show a reduction of approximately 2-3 dB in the farfield which results from a reduction in low-frequency mixing noise due to the creation of vortices in the shear layers. This result substantiates the capability of the computational aeroacoustics technique to evaluate chevron designs for effectively mitigating jet noise, particularly at high Mach numbers.