Effect of Swirl Gas Injection on Bubble Characteristics in a Bubble Column

Swirling gas injection is a well-known technique to improve mass transfer in bubble columns. It can be used to create small bubbles with a high surface area-to-volume ratio, which is beneficial for mass transfer. Swirl gas injection can also be used to create a more uniform bubble size distribution and improve the mixing of gas and liquid in the column. This study aims to determine the impact of swirl gas injection on bubble properties, including bubble shape, size, and velocity. A bubble detection approach has been developed for quick and precise determination of bubble size distributions in gas-liquid systems. Advanced digital image processing, including edge detection and bubble edge recognition, is used in this method. The experiment is conducted in a bubble column at a height of 57 cm and 61 cm. The column had a ring sparger and was made of Plexiglas. Tap water was used as the liquid, while air from an air compressor was utilized as the gas phase. The shape, size, population, and velocity of the bubble are measured using a high-speed digital camera. According to this study, the average bubble size reduced as the impeller speed increased, while the population of bubbles increased when the sparger rotation speed increased from 30 to 150 rpm

The Development of a Preliminary Design for a TidalEnergy Plant

Renewable energy sources are considered a part of the future of energy production in Malaysia. The main objectives of this research are to append a new energy extraction technique that harvests energy from tides and to develop a preliminary design for a tidal energy plant at Kuching Barrage. Knowing the diameter of the turbine, the dimensions of the powerhouse are achieved in conjunction with site conditions. The centerline should be at least below the low water tide so that the tide is at all times guaranteed to be submerged. Based on this, the powerhouse has a 24.61m length, is about 100m in distance across, and its elevation is 36.39m. The construction is located downstream and the centerline habitation at -1.15 and below LSD. The calculated tidal energy plant is comprised of four bulb-type turbines installed at each barrage gate. The bulb-type turbine blades would face the sea site with 11.32m length of the draft tube. This study detailed feasibility study can be implemented

Parallel Computation of Electric Potential in the EHD Ion-Drag Micropump and the Performance Analysis of the Parallel System

The numerical solution of a computationally intensive model becomes more complex in terms of execution time required by a single processor. To speedup the computation, a suitable parallel computing architecture is required. This paper attempts to achieve a fast finite difference solution of electric potential in an EHD ion-drag micropump. A 2D Poisson’s equation is solved on a cluster of low cost computers using MATLAB. Numerical solution is obtained for the different mesh refinements and then the execution time, communication time, speedup and efficiency of parallel system are analyzed. The results showed that the speedup and efficiency of the system increases by increasing the grid points. The results also reveal that for each data size there is an optimum number of workers for obtaining the parallel numerical solution in minimum processing time

Fabrication of Flexible Microfluidic Strain Sensor by Laser Micromachining for Hand Motion Tracking

Various types of strain sensors have been developed for providing reliable monitoring of human health. Microfluidic strain sensors is favourable for such an application due to its outstanding performance under a variety of three-dimensional deformations on the basis of elastic channel deformation. In this study, we report for the first time laser-machined micro-channels on fabricated epoxy substrate. Fabrication of flexible microfluidic sensor using soft clear epoxy is investigated. A ratio of 100:30 of epoxy resin-to-hardener results in a flexible and elastic epoxy layer. Laser micromachining (ablation) technique at varying parameters is conducted using Taguchi Experimental Design. Low number of passes for both kerf depth and kerf width gives an optimum response, while laser power and laser cutting speed differs for kerf width and kerf depth. Microstructure imaging is carried out using scanning electron microscopy for heat-affected zone examination

Degradation of a dielectric barrier discharge plasma actuator

Dielectric barrier discharge is vulnerable to ion bombardment, radical species or ultraviolet radiations that can be emitted by plasma filaments in air under atmospheric pressure. In our experiments, traces of degradation on the actuator surface can be observed by naked eye after the discharge operation. The degradation could come from the non-uniformity of the electric field. Despite the degradation marks, some scratches due to the corona discharge process can be seen on the dielectric surface. The parametric study in this study reveals that the degradation on the actuator panel is subjected to a failure rate that increases with the cumulative time of plasma operation and the magnitude of supplied voltage. Besides, this study suggests that the severity of degradation can be lessened for a symmetric and larger gap design plasma actuator, since the concentration for the ion bombardment can be weakened at a particular discharge area

Effect of Number of Electrodes on Electrical Performance of Surface Dielectric Barrier Discharge Plasma Actuator

Dielectric barrier discharge (DBD) represent their wide application in controlling aerodynamic flow by plasma actuators. Their effectiveness is affected by the shape, type size, and thickness of electrodes. This paper investigates the influence of the number of electrodes on the electrical functioning of surface DBD plasma actuator. For this purpose, five different configurations of plasma actuator with varying electrodes number from 4 to 8 are tested. The gap between the electrodes and the length and width of each electrode remains constant in all these configurations. It was found that on increasing the number of electrodes and the applied frequency (1 kHz to 5 kHz) the value of maximum withstand voltage was decreased. However, the discharge power was increasing slightly on increasing the number of electrodes. This slight change in discharge power resulted in the significant plasma formation on the surface of the plasma actuator, the effect was visually captured by a CCD camera

Determination of Potential Tidal Power Sites at East Malaysia

Tidal range energy is one of the most predictable and reliable sources of renewable energy. This study’s main aim is to determine potential sites for tidal range power in East Malaysia, by analyzing tidal range distributions and resources and the feasibility of constructing barrages. Investigation was conducted in 34 sites, estimating their potential energy outputs and studying their areas for constructing barrages. Only 18 sites were marked as appropriate for constructing a tidal range energy extraction barrage. The highest potential power was found in Tanjung Manis, and its maximum capacity was calculated as 50.7kW. The second highest potential of tidal power extraction was found in Kuching Barrage at Pending, where an energy harvester could produce electric power up to 33.1kW

Tidal energy assessment with hydrodynamic modelling

The increasing demand for sustainable energy generation brings a need for tidal current energy resource exploration around the globe. Hydrodynamic modelling is an essential aspect to explore macro tidal sites. In the current research paper, a 2D hydrodynamic model is set up by utilizing the numerical application of Delft3D. The model is validated against the database results and the two macro tidal sites are identified along the coastline of Sarawak, Malaysia. The maximum available kinetic energy flux at the identified location is 0.6 kW/m2, during peak neap tide hours. This stands as a sound justification to have a detailed tidal energy assessment study in this area in future research