Impact behaviour of aluminum particles upon aluminum, magnesium, and titanium substrates using high pressure and low-pressure cold spray

This study is focused on the impact and residual stress behaviour of aluminum component repair using aluminum powder via two different types of cold spray processes; high pressure cold spray (HPCS) and low-pressure cold spray (LPCS). It has been carried out via smoothed particle hydrodynamics simulations, comparing aluminum substrate with other lightweight materials such as titanium and magnesium. The obtained results have shown that the impact behaviour is influenced by velocity, porosity, deformation behaviour, flattening ratio, total energy and maximum temperature. The aluminum particles impacting on aluminum substrates using LPCS is slightly deformed, with the smallest flattening ratio leading to less pore formation between the particles. This has subsequently resulted in good coating quality. Furthermore, HPCS has contributed greatly to the deposition of particles on the heavier and harder substrate, such as titanium substrate. Thus, the overall result indicates that LPCS is better for repairing aluminum component compared to HPCS

Characterization of Crude Palm Oil (CPO), corn oil and waste cooking oil for biodiesel production

Biodiesel production is the reaction of raw oils with mixing and heating within catalyst and methanol. The raw oils usually come from vegetable oils and animal fats. Vegetable oils are a promising feedstock for biodiesel production since they are renewable in nature. Nevertheless, the physical properties of biodiesel pose some acute problems when used in an unmodified engine. It is important to diesel and biodiesels because it impacts components such as the fuel pump. Therefore, this paper intends to investigate the properties of biodiesel samples in terms of viscosity, density, flash point and acid values at different bio lipids and different mixing time. The evaluation is carried out on the three types of biodiesels: CPO, corn oil, and waste cooking oil. Methanol was chosen over the others for the transesterification process because it was cheaper. The esterification process, which reduces the amount of free fatty acids in the crude oil, will be performed with the help of an acid catalyst. Alkaline catalysts, in contrast, are used for the transesterification process. The comparison of all the samples shows that CPO is the better biodiesel than the other due to the physical properties of kinematic viscosity, density and flashpoint

File And Pc-Based CNC Controller Using Integrated Interface System (I2S)

STEP file is known as a CAD neutral file which stands for Standard for the Exchange of Product model data for the next generation of data model between CAD/CAM and CNC system. It contains three-dimensional data in ISO 10303-21 format which ultimately all CNC programs can recognize. Now however, not all documents in the STEP file are appropriate for programming CNC G-Code. This paper explicates the design, development and testing of an Integrated Interface System (I2S) using knowledge discovery approach. The objective of this study is to provide helps for understanding the STEP-NC machining operation protocol. The system provides function of reading and extracting applicable data related with the machining functions from STEP file, that eventually write file format Geometrical Code (G-Code – ISO 6983) as an output file. G-Code is known as one of the low-level programming languages in CNC system. The sample of machined block designs from 3D CAD modeler where the features need to be machined from a blank workpiece and saved in the STEP neutral file format. In this work, the simulation in the Mach3 software and physical machining using 3-axis CNC milling machine installed with PC-based CNC controller has been validated

A comprehensive review of the influences of nanoparticles as a fuel additive in an internal combustion engine (ICE)

Nanofluid is a colloidal mixture consisting of nano-sized particles dispersed in a liquid medium. It improves heat transfer properties and promotes high energy efficiency in a wide spectrum of engineering applications. In recent years, particularly in the automotive industry, the addition of nanofluid in diesel/biodiesel as an additive for ICE has become an attractive approach to promote enhanced combustion efficiency and emission reduction due to their superior thermophysical properties. Many researchers have previously demonstrated that the addition of nanoparticles in diesel/biodiesel fuel improved the overall engine combustion characteristics. As a whole, this study aims to summarize the recent research findings related to the effect of nanoparticles on the fuel properties and engine combustion efficiency. Furthermore, different types of additive blended with varying fuel properties are also compared and discussed. Lastly, the advantages and prospects of using nanofluid as an additive fuel are summarized for future research opportunities

Piston surface pressure of piston- cylinder system with finite piston speed

Understanding the thermodynamics' fundamental are important for the advance of energy and environmental technologies. The study aims to derive an expression of the average pressure on the piston surface, pps in an adiabatic piston-cylinder system during an irreversible process with finite piston speed using the kinetic molecular theory. Expressions for the average pressure on the piston surface, pps are derived from the change of momentum and change of energy. The Maxwell- Boltzmann distribution is used to estimate the gas molecule velocities. The piston surface pressure obtained from the change of momentum is 37.18% lower than that obtained by the previous study. The piston surface pressure obtained from the change of energy is 26.94% lower than that obtained by the previous study

Numerical analysis for irreversible processes in a piston-cylinder system

A numerical analysis for the irreversible process in an adiabatic piston-cylinder system has been conducted. Axisymmetric compressible momentum and energy equations were solved numerically to obtain the state quantities of the system using the laminar flow model. The numerical method is based on the combined Implicit Continuous-fluid Eulerian technique and the Arbitrary-Lagrangian-Eulerian method. The computations were performed for a single compression process and a single expansion process with the piston velocities of ±1 m/s, ±2 m/s, ±4 m/s, ±6 m/s, ±8 m/s and ± 10 m/s and for cyclic compression and expansion processes with sinusoidal velocity variation. It is found that the piston velocity has effects on the state quantities of the piston-cylinder system and it experienced an irreversible process when the piston moved with an infinite velocity. However, the process can be treated as a polytropic process and the polytropic exponent is approximately equal to the adiabatic exponent, n ≈ γ when the piston velocity is less than ±10 m/s. In the cyclic process of 10,000 rpm, the internal energy increases 0.037% of the compression work in each cycle

A review of passive methods in microchannel heat sink application through advanced geometric structure and nanofluids: Current advancements and challenges

Microchannel heat sink (MCHS) is an advanced cooling technique to fulfil the cooling demand for electronic devices installed with high-power integrated circuit packages (microchips). Various microchannel designs have been innovated to improve the heat transfer performance in an MCHS. Specifically, the utilisation of nanotechnology in the form of nanofluid in an MCHS attracted the attention of researchers because of considerable enhancement of thermal conductivity in nanofluid even at a low nanoparticle concentration. However, a high-pressure drop was the main limitation as it controls the MCHS performance resulted from heat transfer augmentation. Therefore, this study aimed to critically summarise the challenges and limitations of both single and hybrid passive methods of MCHS. Furthermore, the performance of nanofluid as a coolant in the MCHS as affected by the type and concentration of nanoparticle and the type of base fluid was reviewed systematically. The review indicated that the hybrid MCHS provides a better cooling performance than MCHS with the single passive method as the former results in a higher heat transfer rate with minimal pressure drop penalty. Besides that, further heat transfer performance can be enhanced by dispersing aluminium dioxide (Al2O3) nanoparticles with a concentration of less than 2.0% (v/v) in the water-based coolant

A review of passive methods in microchannel heat sink application through advanced geometric structure and nanofluids: Current advancements and challenges

AbstractMicrochannel heat sink (MCHS) is an advanced cooling technique to fulfil the cooling demand for electronic devices installed with high-power integrated circuit packages (microchips). Various microchannel designs have been innovated to improve the heat transfer performance in an MCHS. Specifically, the utilisation of nanotechnology in the form of nanofluid in an MCHS attracted the attention of researchers because of considerable enhancement of thermal conductivity in nanofluid even at a low nanoparticle concentration. However, a high-pressure drop was the main limitation as it controls the MCHS performance resulted from heat transfer augmentation. Therefore, this study aimed to critically summarise the challenges and limitations of both single and hybrid passive methods of MCHS. Furthermore, the performance of nanofluid as a coolant in the MCHS as affected by the type and concentration of nanoparticle and the type of base fluid was reviewed systematically. The review indicated that the hybrid MCHS provides a better cooling performance than MCHS with the single passive method as the former results in a higher heat transfer rate with minimal pressure drop penalty. Besides that, further heat transfer performance can be enhanced by dispersing aluminium dioxide (Al2O3) nanoparticles with a concentration of less than 2.0% (v/v) in the water-based coolant

The effect of triangular cavity shape on the hybrid microchannel heat sink performance

Rapid development in the electronic industry witnesses many tremendous advanced technologies which work with high power density. As a result, an advanced cooling technique, namely, microchannel heat sink (MCHS) is required to fulfil the current cooling demand due to unpredicted increment of power density in a high-density microchip. A microchannel heat sink performance can be enhanced by improving the working fluid properties and or improving the design of cooling passage that contributes to the augmentation of heat transfer rate. In this paper, the optimization of hydrothermal performance was conducted by studying the effect of triangular cavity pitch location (Cavity 1, CV1: 60 µm; Cavity 2, CV2: 100 µm; Cavity 3, CV3: 140 µm) on fluid flow and heat transfer characteristic in the hybrid microchannel heat sink (Triangular cavity with rectangular rib microchannel heat sink, TC-RR MCHS). The result revealed that the TC-RR MCHS with the triangular cavity pitch location of 140 µm (CV3) showed superior performance over other pitch locations (CV1 and CV2) for all the Reynolds number (Re number). The optimum Performance Factor, PF, achieved by CV3 pitch location was 1.76 at Re number of 350. It indicates that the proposed design with CV3 is suitable for the technology that requires less pumping power consumption

Numerical analysis for irreversible processes in a piston-cylinder system

A numerical analysis for the irreversible processes in an adiabatic piston-cylinder system was conducted using the Lam & Bremhorst low Reynolds number turbulence model (LB1) modified for compressible flows by Sarkar and Balakrishnan (LB1S model). Two-dimensional compressible momentum equation and energy equation which includes the substantial derivative of pressure and the viscous dissipation terms were solved numerically to obtain the state quantities of the system. The computations were performed for a single compression process with constant piston velocity, up=-10 m/s and for cyclic compression and expansion processes with sinusoidal velocity variation. The selected rotation speed ranges from 1000 to 50,000 rpm. The computations were performed for 10 cycles. It was found that the sinusoidal piston velocities have effects on the state quantities of the piston-cylinder system and it experienced an irreversible process when the piston moved with a finite velocity. For the case of single compression process, the flow was laminar when the piston velocity was below 10 m/s. In the cyclic processes, the flow was turbulent when the rotation speed is in the range from 2000 to 50,000 rpm. However, for the case of 2000 rpm, the flow was laminar only at the first cycle. This is due to the turbulent viscosity that is lower than dynamic viscosity (1.862×10-5 Pa s). It was found increasing the rotation speed will increase the value of the turbulent viscosity. In the cyclic processes for the cases N = 1000, 10,000 and 50,000 rpm, the internal energy increased by 0.003%, 0.028% and 0.289% of the compression work in each cycle, respectively