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A micro turbine are tiny gas turbines that can generate both electricity and heat. It has small capacities that vary from 25 kW to 250 kW. This article aims to determine the value of enthalpy, entropy, energy and exergy in each state, which is then used to calculate percentage of efficiency and exergy destruction on each component. The research result shows that, the largest percentage of efficiency is in the startup component burner and the smallest efficiency is found in the steam reformer. Meanwhile, in exergy destruction, the steam reformer is a component that has exergy the largest destruction, and the startup burner has the smallest exergy destruction. The results of the analysis process show that the optimal mass flow rate is one of the keys to designing a heat exchanger. Where, pressure drop, and convection coefficient increase with increasing flow rate mass. However, the optimal mass flow rate is also highly dependent on heat exchanger dimensions. [ABSTRACT FROM AUTHOR]

The energy and exergy analysis of the Riau Andalan Pulp and Paper (RAPP) Pangkalan Kerinci are described in this article. This article's main goals are to study the system components independently and to locate and quantify the locations with the greatest energy and exergy losses. The analysis with the first law and second law of thermodynamics which are able to observe comprehensively the irreversibility of each component in the system is carried out due to the low efficiency of the steam power plant. The investigation is performed with the actual data obtained from the plant. From the evaluation results, the Pump II Component has the highest Exergetic Efficiency (95%), while the Feed Water Tank (FWT) component has the lowest Exergetic Efficiency (30.68%). The Boiler component has the largest exergy destruction value (454.2548 MW), while the Pump component has the smallest exergy destruction value (0.0006 MW). Next, the FWT component has the largest Exergy Destruction Ratio value (69.32%), while the Pump I component has the smallest Exergy Destruction Ratio (0.79%) at the steam power plant. In addition, the investigation of the ambient temperature effects on the performance of the plant was also carried out. From the results that have been investigated, the ambient temperature significantly affects the performance of each component. Some components are at their best performance when the ambient temperature reaches 23°C and the condenser has the lowest efficiency when the environmental pressure in the power plant reaches 1.5 bar (64.8%) [ABSTRACT FROM AUTHOR]

This study discusses the fluidic oscillator using computational methods. The analysis was carried out in a transient state with the URANS equation. The turbulence model used is k-ω SST. The fluidic oscillator was analyzed by varying the size of the fluidic oscillator by doubling the baseline and reducing its size by half. The analysis was carried out using the magnitude velocity curve to time changes, velocity profiles, and fluid flow contours. Based on the results of the velocity analysis at two points, it can be concluded that the fluidic oscillator can produce an oscillating fluid flow with a maximum velocity of almost eight times the inlet velocity. Meanwhile, the velocity profile in the feedback channel is alternately positive and negative due to the backflow phenomenon. In the mixing chamber, an adverse velocity profile can also be found, indicating the mixing flow's presence. Based on the magnitude velocity analysis results, it can be concluded that changing the dimensions by increasing the size of the fluidic oscillator does not produce significant changes. Meanwhile, the velocity profile on the feedback channel shows a significant change in model 3. The velocity contour shows that at t=4 s, the fluid from fluidic oscillator model 1 has lost its oscillator effect. However, this is not the case with the model 2 and 3 fluidic oscillators. [ABSTRACT FROM AUTHOR]

The aerodynamic characteristics of MPV vehicles were studied to obtain comprehensive information. The study was conducted computationally using the RANS equation on the k-ω SST turbulence model. The three vehicles selected in this study are Vauxhall Zafira C Tourer, Volkswagen Touran, and Mazda MPV II 2.3. These vehicles were chosen because they are quite in demand in Indonesia. Each vehicle was analyzed at three different speed variations, namely 20 km/h, 50 km/h, and 100 km/h. This research aims to study the characteristics of the drag coefficient (Cd) of several MPV vehicles. In addition, this study also analyzes the effect of changes in speed on the drag coefficient and its causes. The result of this research is that when viewed from the Cd point of view, the Volkswagen Touran has the smallest drag among the other two vehicles. From the Cd point of view, it can be seen that the Volkswagen Touran has the smallest drag, i.e., 0.75620101 at 20 km/h, 0.782 at 50 km/h, and 0.786 at 100 km/h. It was found that at a speed of 20 km/h, the Volkswagen Touran is still the best because the Cd is small and the power is small at 60,3126 hp. Then at a speed of 50km/h from the point of view of drag and power, the Volkswagen Touran vehicle is superior because the Cd produced is the smallest, and the average power is not much different from each other. At a speed of 100 km/h, the Volkswagen Touran is still superior because of its smallest drag and slightly less power when compared to other vehicles. Overall, when viewed from the Cd and power, the Volkswagen Touran is a superior MPV car because the Cd produced is small, and the power is also efficient. [ABSTRACT FROM AUTHOR]

The energy crisis does not sound familiar today. Human dependence on conventional energy causes adverse effects such as greenhouse gas emissions and environmental pollution. Developing of new renewable energy as environmentally friendly energy is the solution to this problem. Many breakthroughs have been achieved regarding efficiency in developing new and renewable energy. The efficiency of the turbine blades is one of the most significant breakthroughs in achieving maximum performance. Therefore, this research was conducted as a breakthrough in achieving energy efficiency based on aerodynamic performance of airfoil. The computational Fluid Dynamics (CFD) method used to investigate the NACA 4415 airfoil with micro-cylinder adding. This study investigates the aerodynamic performance of airfoil with micro-cylinders with predetermined area and diameters. The variations of the micro-cylinder used are the installation of one micro-cylinder and the installation of two micro-cylinders. The Reynolds number used is 3×106 with an AoA variation of 0-30. The installation of micro-cylinders in this study reduces the aerodynamic performance of the NACA 4415 airfoil. The decrease in airfoil performance can be seen in the inhibited increase in Cl airfoil caused by an excessive increase in Cd. The stall on the micro-cylinder installation is also not able to be appropriately inhibited. However, the performance of airfoil with one micro-cylinder began to appear after the airfoil stalled. In which Cl in the airfoil with one micro-cylinder increased by 37.91%. Meanwhile, the Cl airfoil with two micro-cylinders increased by 25.64%. [ABSTRACT FROM AUTHOR]

This study uses a computational research method with a Computational Fluid Dynamics (CFD) approach. The governing equation used in this research is Reynolds Averaged Navier Stokes (RANS) with turbulence model. The type of airfoil used in this research is the NACA 4415 asymmetry airfoil. Airfoil testing is carried out on variations in Angle of Attack (AoA) and leading-edge models. The Angle of Attack tested in this paper is in the range of 0°-25°. The first modification of the airfoil is to make the airfoil's leading edge in the form of a spinner dolphin. The second modification is to shape the airfoil's leading edge like a rough-toothed dolphin. Modifications to the spinner dolphin proved to have better aerodynamic performance than the rough-toothed dolphin, although there was no significant difference. The optimum AoA achieved by the spinner dolphin is AoA = 8°. Based on the baseline comparison, the percentage of drag on the spinner dolphin was reduced by 5.6162. While on the rough-toothed dolphin, it decreased by 4.9116. [ABSTRACT FROM AUTHOR]

Synchronous motor technology is more energy-efficient and cost-effective. It significantly impacts the development of science, especially in the field of transportation and industrial engineering. A synchronous motor is a brushless DC motor (Brushless Direct Current) which is a motor that has good efficiency, is more reliable, and has a longer life. The magnetic field comes from permanent magnets in the rotor and coils in the stator. The brushless DC motor system refers to the concept of an electromechanical circuit with a responsive and energy-efficient drive system. The system is built through electromechanics, electronic circuits, sensor systems, logic circuits, or micro-control algorithms. This study aims to develop a new method for designing a practical and efficient Synchronous Motor using a computational model as a simulation medium for the research results to be obtained. The finite Element Method (FEM) is a numerical technique for determining electrical machines' electromagnetic parameters using the machine's geometric dimensions and material properties. The method used is the finite element method using the Ansys Electronic 2018 software. The motor has good performance with electric current in each phase around 1.5 kA and a magnetic field flux of 0.02 Wb. the speed of the synchronous motor remains constant at 13300 rpm, which produces an induced line voltage and an induced phase voltage at a value of a maximum of 249.72 (volts) and 124.93 (volts). [ABSTRACT FROM AUTHOR]