Rekayasa Mekanika

Aerodynamic Characteristics of Amphibian Aircraft Using Computational Fluid Dynamics (CFD) Method

2023-09-19T03:18:27+00:00

Aerodynamics is the study of the flow field and the forces caused by relative motion between the aircraft (aircraft body or other parts) and the surrounding air. The study of aerodynamics involves calculating the speed, temperature and pressure that occur due to the relative motion of an object in the air. The pressure and frictional forces acting at every point on the surface of an object cause lift, drag, and side forces. One way to calculate the aerodynamic characteristics of the aircraft is by using the CFD method. Computational fluid dynamics or CFD is the analysis of systems involving fluid flow, heat transfer and related phenomena such as chemical reactions by means of computer-based simulations. The goal to be achieved is to determine the correlation of the lift coefficient and drag coefficient of the seaplane, it is necessary to carry out a CFD simulation. The research methodology was carried out using Computational Fluid Dynamics (CFD) simulations at speeds of 20 m/s, 40 m/s and 60 m/s and Angle of Attack 0°, 5°, 10°, 15°, 20°, 25° dan 30°. The simulation results show that the lowest value is at AoA 0^° and the highest is at AoA 30°. for each speed, but at a speed of 20 m/s the highest value is at AoA 25°because at AoA 30° the value decreases causing a stall . value increases with each variation of speed and angle of attack.

Comparison of Volume Fraction of Carbon Tow/Epoxy Composites Between Vacuum Infusion Manufacturing and Filament Winding Methods

2023-09-19T03:53:24+00:00

Several methods can be applied in composite manufacturing, including the vacuum infusion and filament winding methods. In order to apply this method in the manufacture of composites, it is necessary to know which produces composites with a good target ratio of fiber and resin, namely 60%/40%. The aim of this research is to compare the manufacturing methods that produce the distribution of fibers and resins that are close to the target. The composites in this study used a carbon tow reinforcement material with a matrix, namely araldite LY5052 epoxy resin and aradur 5052 CH hardener. In composite manufacturing, there are three stages, namely molding preparation, process manufacturing, and demolding. Then SEM photo observations were made on the specimen pieces from the composite results with three different locations. Of the two methods, vacuum infusion produces SEM photos with denser fiber distribution than filament winding and voids produced in the filament winding manufacturing method. The volume fraction of the test on the vacuum infusion sample with an average yield of 56.79% and 54.01% for filament winding.

The Effect of Vacuum Condenser Pressure on Steam Turbine Generator Performance

2023-09-19T03:59:28+00:00

Condenser is an main equipment on power steam electricity system generator. Condenser is an head exchanger that functions as a phase changer from the steam turbine output into water, which is where water results condensation the will pumped to HRSG for used back. Vacuum condenser working for speed up the condensation process in the condenser. PT. PLN (Persero) UPDK keramasan is generator electricity consists of 2 units from gas and steam power plant with power by gas turbine generator of ± 27 MW and a steam turbine generator of ± 13 MW so that the total each unit is 40 MW. This research to determine of effect vaccum condenser pressure of condenser with power turbine, and efficiency thermal. calculation obtained at a vacuum condenser pressure of 15,41 kPa at a turbine power was 9681 kW, and obtain efficiency thermal was 20,39%. On pressure vacuum condenser 15,09 kPa at a turbine power was 9602 kW, and obtain efficiency thermal was 20,24%.

Maintenance of Cutting Return Bends Machine

2023-09-19T04:04:36+00:00

The cutting return bend machine itself adopts a programmable logic controller for the interface control center between man and machine for its operation. With the characteristics of high-level optimization, speed, comfortable operation, high precision, reliable performance and attractive appearance. For the use of the cutting return bend machine itself, which is used for the production of u-shaped tubes which will later be used for the manufacture of evaporators and condensors. Maintenance also includes all necessary actions to be able to maintain and maintain product quality so that there is no damage or disruption to the machine so that producing products can achieve the targets as desired by the company. From the observations made, it is found that the problems that occur in the cutting return bend machine at PT. Panasonic Manufacturing Indonesia are damage to the mandrell, stripper,and problem with the bending mechanism. The solution of these problems are need to maintenance of the machine, which is corrective maintenance, preventive maintenance, predictive maintenance, and even emergency maintenance.

Failure Analysis of Turbine with Vibration Analysis Method

2023-09-19T04:09:23+00:00

In the operation of the turbine, various problems can occur which cause damage, one of which is caused by vibration. Vibration analysis is one of the supporting factors to minimize excessive vibrations in the turbine. Predictive maintenance activities in the form of conditional monitoring vibration or vibration monitoring of actual conditions are carried out to determine the symptoms of damage to the turbine. Measurements were carried out using VibeXpert II based on ISO 18016-5 standards with operating conditions of 70 MW turbine load and 500RPM rotation measured on the DE Turbine and NDE Generator. The highest value is in the horizontal DE Turbine 77.04 µm (pk-pk) and 104 µm (pk-pk) on the NDE Generator. This value is already in the acceptable zone to operate in the long term. The results of spectrum analysis that can be identified as the cause of the vibrations that occur are indications of unbalance on the DE Turbine and Overhung on the NDE Generator.

Performance Analysis of Centrifugal Feed Pumps

2023-09-19T04:17:57+00:00

To support the optimization of operations at a refinery, a tool is urgently needed that can help process crude oil into a product. The centrifugal feed pump P-100/4 is a pump that operates in a distillation unit where the distillation unit functions to process oil from crude oil into products such as residue, diesel ph, diesel, kerosene, naptha and petrasol. The centrifugal feed pump P-100/4 aims to pump crude oil from tanks 101 and 102 to provide feed to furnace 5, before entering the crude oil furnace which is preheated in heat exchangers 1,2,3 to 4. The P-100/4 feed centrifugal pump is driven by a motor. In this paper more focused on the operation and maintenance of centrifugal pump P-100/4 feed. This data collection method is carried out by conducting interviews with field supervisors, and observing the pump unit directly, and other supporting books. The results obtained are: With a good and correct pump operator system and with capable and skilled operators, the pump operation will always be in good condition, and the life of the pump will be longer. The NPSHa value of the P. 100/4 mash pump meets the operating specifications, which is greater than the NPSHr. So the P.100/4 pump does not experience cavitation so the pump work is very stable. The efficiency price of the P. 100/4 feed pump is 68.40%