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The effect of Weber number on the dynamic contact angle of single impacting droplet onto inclined hot surface has been studied experimentally. The Weber number variations are 10, 30 and 60. To adjust the Weber number variations, the droplet injector is modified at various height. In the present study, stainless steel is placed as heated material while the surface temperature is adjusted at the desired temperature, they are 100°C - 220°C controlled by the data logger. The droplet phenomena was recorded by high-speed video camera with frame rate 4000 fps and attached with the macro lens. The objectives of this studied are to understand the regime phenomenon, the time variations, and other important parameters of a droplet impacting onto an inclined surface. It was found that (1) the regime of droplet phenomena has specific models for each range of temperature, (2) The increase of Weber number decreases of contact time at temperature 200°C and 220°C, (3) The increase of Weber number increases the spreading ratio significantly at 200°C and 220°C, (4) The increase of Weber number will have significantly affected to result of advancing and receding contact angle are presented. [ABSTRACT FROM AUTHOR]

Enhancing heat transfer performance in condensation provides challenge since working fluid in condensation system almost have low surface tension which more difficult to provide droplet on the surface than high surface tension fluid. Providing droplet is believed as one of the method for increasing heat transfer since droplet offers small condensate with high contact angle and leads to roll off easier than thin film condensate. Whereas the conventional method for low surface tension fluid problem is by using extended area to enhance the heat transfer. Practically, the hydrophobic surface coating to induce droplet on the surface is easier than extended area method. Unfortunately, hydrophobic surface coating does not always show good performance to induce droplet especially for low surface tension fluid. The wettability of surface holds important role to determine the mode of condensation, dropwise or filmwise condensation. Beside of that, the surface tension of working fluid also influences the mode of condensation since leading to adhesive force. Here, the analysis of surface wettability and surface tension of fluid for producing droplet would be investigated. [ABSTRACT FROM AUTHOR]

Dissolution mass transfer inside porous media is important in various hydrogeology applications. However, the effect of particle size to the dissolution mass transfer remains an unsolved issue. One of the limitation of studying this phenomenon is the limitation in measurement technology. Direct observation of the trapped phase inside porous media cannot be observed directly. In this work, we utilized micro-tomography measurement technology to observe the trapped phase inside the porous media. The same shape of particle size was used but the size and the distribution was varied to demonstrate the change in particle size characteristics of the porous media. We found that the mass transfer coefficient decrease significantly (about one order of magnitude) at some threshold value of particle size. We believe that the reason behind it is the appearance of the bypassing phenomena during the dissolution process. [ABSTRACT FROM AUTHOR]

Unmanned Aerial Vehicle is a type of aircraft that has a very wide application. In this study, numerical calculations were performed using ANSYS Fluent software to find the effects caused by the implementation of the area rule theory to the fuselage of a surveillance Unmanned Aerial Vehicle (UAV). The area rule theory usually used on the transonic aircraft while the surveillance UAV is a very low speed aircraft. The study was conducted by varying four prototype of UAV fuselage with different volume distributions on the area around the wing without varying other part such as wing, tail, etc. The study was conducted using the k-omega SST viscous model (k-ω SST) with the mission profile having a distance of 200 km, a ceiling of 500 m, and a speed of 20.8333 m/s. Mesh is made of polyhedral with a very good standard of skewness quality and mesh orthogonal quality. The results of this study indicate that the implementation of the area rule theory to the fuselage of a surveillance UAV didn't affect the drag force that occur on the aircraft, but the implementation of the theory increased the lift force occur on the aircraft, although it's not significant. [ABSTRACT FROM AUTHOR]

Sediment from the environmental damage and erosion in the watershed will settle in the bottom of the reservoir. It can reduce the capacity of the reservoir. Airlift pump technology is one effective method for lifting the sediment from the reservoir. The airlift pump has a simple working principle, the pressurized air is injected into a riser pipe containing water, so those air bubbles are created. Air bubbles move upward and it will lift the around liquid due to interface friction. In this present experimental study, the airlift pump was designed by the transparent acrylic pipe with 3.4 m length, and 56 mm inner diameter. Air and water were the working fluid. The water column in the riser pipe was set-up corresponds to the submergence ratio from 0.5 to 0.68, and the superficial gas velocity was changed from 0.00677 to 0.677 m/s. The mouth bell suction head was placed on the lower end of the riser pipe to mounting the two injectors. It was placed on the lower end of the suction head with the 45° direction of the horizontal and opposite output direction to produce the swirl flow. A high-speed camera was used to record the flow pattern. As the results, we know that the higher the submergence ratio, the greater the superficial water velocity at the same of the superficial gas velocity. It is implying the greater the efficiency and effectiveness of the pump. The swirl flow at the suction head is generated when QG>2.8 m3/hr. The consecutive slug becomes the main factor in the existence of the pulsation effect when the pump is operated. The variation of superficial gas velocity is the dominant effect of change in the flow pattern than the variation of the submergence ratio. [ABSTRACT FROM AUTHOR]

In lifting fluid and sediment by using upward force injected by gas through upriser, airlift pump has certain flow characteristics. The Airlift pump flow characteristics had been explored in the previous studies, yet those studies only focused on two phase airlift pump. For this reason, the recent study aimed at revealing the flow characteristics of three phase airlift pump. These characteristics was observed experimentally for different particle diameter by using liquid and gas as working fluid. When the airlift pump was operated by using solid material, the flow occurring in the upriser pipe was three phases. The current airlift pump experiment used a compressor to inject gas on the injector. The internal diameter of the upriser pipe of 56 mm and the total height of 3400 mm. This experiment was conducted on variable particle diameter mesh 24-20 and 16-12. The variation of air discharge given were 60 l/min, 70 l/min, and 80 l/min with atmospheric conditions. The research matrix was obtained by combining two variables. The experimental results indicated that (1) the velocity of air discharge has significant effects in lifting the particles as gas hold up occurring was greater, (2) the greater the air discharge was given, the greater gas hold up occurring in the flow, (3) the higher the air discharge was given, the higher upriser gradient, so the lifting capability became greater since the great pressure opposed the gravity, (4) the small particle diameter was used in the air lift pump system, the greater the lifting particle due to greater friction between particles and water. [ABSTRACT FROM AUTHOR]

Airlift pump can be used as an alternative to lift the sediment from the the water. The airlift pump employed in this study was a conventional type that used a compressor on the injector system. This study aimed to determine the characteristics of the airlift pump in a three-phase flow. In the experiments, the sludge used was solid spherical particles with 1.43 mm as the particle average diameters. The experiment operated upriser pipe with an inner diameter 56 mm and 3.4 m height. The submergence ratio of the upriser in water was: 0.5, 0.62, and 0.74, while the supplied air flow rate was 60 l/min, 70 l/min, and 80 l/min under atmospheric conditions. The research matrix was obtained by combined two variables, which were the submergence ratio and the airflow rate. Further, it was used to determine the effect on the flow rate of discharge solid particles, the flow rate of discharge water, and the pressure gradient. Visual observation was utilized to determine the behavior of the three-phase liquid-gas-solid flow in the pipe. The results were acquired from visual observations that depicted the flow regime occurrence, slug, churn, and annular. Moreover, the measurement results of the flow rate and pressure gradient discovered that in the submergence ratio and the injected air flow rate had a significant influence on the flow characteristics. [ABSTRACT FROM AUTHOR]

To design a radial compressor there are many geometry parameters that must be considered. Leading edge shape, trailing edge shape and of course the shape of the unit blade itself. Geometry parameters of the impeller defined by its operation condition. Radial compressor with high rotational velocity (high rpm) will have more looked down leading edge than radial compressor that works in the lower rpm regime. The radial compressor with high pressure ratio usually has more radial trailing edge than radial compressor with low pressure rise. In the designing radial compressor rotor, or its commonly known as impeller, we can define the blade leading edge by using relative velocity and tangential velocity. Defining blade leading edge usually more easier than defining traling edge section. There are several consideration before we can define trailing edge shape of the impeller. Number of blade, flow angle out from the impeller and radius outer impeller are some things that need to included in the calculation. In this study will be assessed the effect of trailing edge shape (based on the beta angle) to the radial compressor performance especially on isentropic efficiency and the pressure rise, CPR. By using CFD, Computational Fluid Dynamic, will be predicted and compare the trend line in every single model of impeller trailing edge. With this study, hopefully. could make a kind of margin how far we can tolerate deviation in at the trailing edge when we do the manufacturing process. [ABSTRACT FROM AUTHOR]

Gas lift is one of the most popular artificial lift methods available in the oil and gas industry. It relies on reducing fluid density, henceforth reducing the pressure gradient along the wellbore and eventually enables liquid to be lifted at ease. As Indonesia's oil fields are reaching mature state, optimization in artificial lift method is one of the most feasible actions and it carries lower risk compared to injecting foreign substance into the reservoir. Previous efforts in optimizing gas lift design has been revolving around the application of Gas Lift Performance (GLP) curves, where changes in oil recovery is monitored as a function of gas injected. As established as this method nowadays, it still carries a heavy burden when dynamic pressure and rate changes should accounted in a very small time step. Therefore, the application of mechanistic modeling can be an alternative to reduce complexity in modeling dynamic GLP curves. This research presents a novel extension of Flow Pattern Map (FPM) as a function of tubing size in order to map optimum injection gas rate. A new correlation is also presented as a correction factor for highly utilized tubing sizes in oil and gas industry, therefore increasing the versatility of FPM application in gas lift optimization. [ABSTRACT FROM AUTHOR]

Particle separation is an important stage in industry, especially in chemical and mineral industry. Some common methods in separation are filtration, gravitation and centrifugal (cyclone). A new method of separation, namely fluidized bed, needs to be explored because it produces low pressure drop and high efficiency. Experiment was performed using bio-solar (diesel fuel) as fluid and silica gel with radius 0.8 mm and 3 mm as solid particle. The goal of experiment is obtaining maximum separation of small particle (0.8 mm) and maintaining minimum separation for big particle (3 mm). Fluid velocity is ranging from 0.034 – 0.118 m/s where the slowest velocity is still above minimum fluidization velocity for small particle, and the maximum velocity is still smaller than terminal velocity of big particle. There are 3 (tree) outlet height of fluidized bed, namely: 0.3, 0.6 and 0.9 meter. According experiment result, the increase of velocity will slightly increase pressure drop but it highly increases separation percentage. An optimum separation occurs on velocity of 0.118 m/s and outlet 0.9 meter where separation efficiency of small particle as high as 98 percent and big particle separation is less than 2 percent. [ABSTRACT FROM AUTHOR]

Lymphedema caused by the damage and/or blockage of lymph flow resulted in the accumulation of protein-rich- fluid in the interstitium. To prevent the chronic phase of Lymphedema, the diagnosis for the earlier stage (Stage 0-I) of Lymphedema is needed. Unfortunately, the early stage of Lymphedema cannot be diagnosed clinically. For that purpose, we developed a simplified 2-D CFD model of capillary fluid exchange in a cross-section of the human upper limb to predict albumin (protein) and fluid (water) distribution in the interstitium (subcutaneous tissue) which is related to the mechanism and characteristic of the early stage of Lymphedema. Our model shows the distribution and total amount of albumin and water as a function of space and time. The filtration from blood capillaries increased the amount of water and albumin in the interstitium that induced the enhancement of interstitium pressure. The increasing of interstitium pressure served as a driving force for the lymphatic system to initiate the absorption mechanism. The impaired of the lymphatic system would cause the absorption mechanism did not work properly which will result on water and albumin accumulation in the interstitium. Water and albumin temporary accumulation indicated the occurrence of Stage 0-I Lymphedema. [ABSTRACT FROM AUTHOR]

This study aims to visualize the non-premixed flames in a radial flow burner equipped with swirl vanes and to analyze the stability of flames. The study was carried out using concentric pipes, an air pipe 2 inch in diameter and a fuel pipe 6 mm in diameter. Fuel was injected through 3 holes with diameter of 1.5 mm. The fuel used is LPG and the air is supplied from a blower with a speed range of 3.8-6.6 m/s. The air passed a swirl vane with angles Ø=10°, 30°, 50°. The stability limits of the flame at fixed air velocities were obtained by increasing the fuel velocity until the flame blowed out. The fuel velocity were then plotted into a flame stability diagram. Furthermore, structures of the flame were visualized from ignition until the flame blows out using video camera with 240 fps. The results show that in general larger angle of the swirl vane increases levels of flame stability. At relatively low air speeds, the swirl with Ø=50° shows the broadest stability limits compared to Ø=10° and 30°. While at higher air velocity the stable flame area of the swirl with Ø=50° is narrower compared to Ø=30°. At the blade angle Ø=10° and Ø=30 ° increase in air velocity causes an expansion in flame stability, whereas at Ø=50° increase in air velocity causes a decrease in flame stability. [ABSTRACT FROM AUTHOR]

Water tunnel (WaTu) visualization techniques have been in high demand to analyze aerodynamic characters in the delta-aircraft model because of clearer and more detailed results. The visualization was used to observe the aerodynamic characteristic of the rolled-up vortex phenomenon on delta-wing. The difference in fluid and flow parameters became an issue of the accuracy of the results. Therefore, testing parameters need to be analyzed so that the results of the WaTu test have been able to represent the real conditions. This research has varied the velocity to investigate the delta-wing aerodynamic characteristics using GAMA water tunnel. The results were compared with computational fluid dynamics (CFD) results based on WaTu and real (subsonic) conditions, as well as several other references. The results showed a similarity in the vortex breakdown location (VBL) at all flow rates in the WaTu and CFD. The CFD results also showed that the coefficient of pressure (Cp) on the wing had the same results in all tests, both based on WaTu and real conditions. Likewise, for a lift and drag coefficient (Cl-Cd), values for all states approached the same amount with a difference of less than 5%. Finally, the uses of the WaTu method has been able to represent the actual conditions in vortex dynamics cases in delta aircraft with the optimum velocity to produce the best visualization around 0.1 m/s. [ABSTRACT FROM AUTHOR]

Engine performance is a major factor in an automotive competition, including Student Formula SAE (FSAE). One aspect that influence the improving engine performance is the intake system. One of the FSAE regulation atates that all vehicle must use 20 mm resistor o their intake system. With this regulation, the supply of air that enter the engine is very limited. To improve the engine performance, the use of plenum is the intake system can be one of it's solution. The author analyzes the effect of plenum geometry towards the powertrain performance of the seventh generation of Bimasakti car (BM7). BM7 use KTM 450 SX-F, a single-cylinder, 450 cc engine as their prime mover. There are 4 design of plenum that became the independent variable on this research. One of those is the actual design of plenum that has been installed in BM7, the other 3 is a new design that shaped up base on the objective of the research. All those design will be simulated using Ricardo WAVE software and flow simulations using ANSYS software were also conducted to study the flow forms in plenum. The result of this research shows that the used of author's plenum design can increase the maximum power by 7.26% and maximum torque by 20.96% compared to the BM7's actual plenum. From fluid flow simulation, the author know that in some designs, there is amount of air that still move inside the plenum that rub the other air and causes pressure loss. [ABSTRACT FROM AUTHOR]

This study is aimed to obtain the optimal aerodynamics design for the student class formula car for the needs of the Formula Student Japan SAE competition, especially for dynamics events. To achieve these objectives, the following study steps are taken: evaluation of previous design, formulation of design concepts, referring event rules, designing, numerical simulations using CFD software packages, analysis, optimizing, and finalizing designs. Optimizing the undertray performance and analyzing the effect of DRS system is the main focus in this series of studies. The results show that the coefficient of lift is decreasing relatively with an increased undertray inlet angle. The lowest Cl value reached 0.203 with delta 24.25% at 20o undertray inlet. Drag force decreased drastically with the DRS system usage, up to 87% from 101.66 N to 12.86 N at 0o airfoil angle of attack. [ABSTRACT FROM AUTHOR]

An experimental study of the effect of the resonator length on the performance of standing wave thermoacoustic (SWTE) engine has been presented. Three different resonators length with an opened end were tested. SWTE consists of several main parts, which are a Hot Heat Exchanger (HHX), a Cold Heat Exchanger (CHX), a resonator pipe, and a stack. CHX and HHX were made of copper with 4 cm length. The stack was 3 cm lamination made of stainless steel wire mesh screens with a mesh number of 10. The resonator pipe was made of stainless steel with an inner diameter of 52.5 mm and we were varied to 630 cm, 1020 cm, and 1410 cm. We used battery charger which has power of 231 W to supply heat power into SWTE. This experiment proved that the SWTE with resonator length 630 cm generated the sound with the smallest onset temperature difference and the shortest time to reach the onset condition, those were 200oC and 1310 s, respectively. It also produced the highest pressure amplitude of 5.272 kPa, the highest acoustic power of 20.6 W, and the highest efficiency of 8.9%. [ABSTRACT FROM AUTHOR]

A close-open thermoacoustic engine was designed, constructed, and tested by using air as working gas. The stack was made of a pile stainless 316 wire mesh with length of 30 mm. In this study, performance and absorption incidental sound energy were investigated by changing the stack porosity. Experimental results show that stack porosity was significantly influence onset temperature, pressure amplitude and acoustic intensity due to viscous losses. The engine achieved a steady working frequency of 87 Hz. Maximum acoustic intensity that can be achieved is 1387 W/m2. Absorption sound power decreases when the hydraulic radius is reduced to the same value as thermal penetration depth. It increases when the thermal penetration depth is greater than hydraulic radius. [ABSTRACT FROM AUTHOR]

Besides the stack, the parameter can convert the heat energy into sound wave, the other parameters are tilted angles and resonator length which also have to be researched. The aim for the research is to obtain an acoustic intensity greater so that the performance of standing-wave thermoacoustic engine is increased. It is affected by tilted angles because the natural convection will be different every tilted angle within thermoacoustic core while the resonator length will mainly affect the frequency of the thermoacoustic engine. The heat transfer characteristics within it are investigated under 3 tilt angles including, - 90°, 0°, and 90°, and also resonator length 390, 780, and 1170 mm. In this study, the acoustic intensity is calculated by the two sensors method. It is found that the pressure amplitude tends to increase with decreasing tilted angles and resonator length. The frequency increases when the resonator length is extended. Nevertheless, it is only has little affected by different tilted angles. Therefore, the acoustic intensity is increased when the tilted angles and resonator length are decreased. [ABSTRACT FROM AUTHOR]

This experimental study is aimed to increase the water fraction (watercut) output in LLCC by installing a baffle in order to prevent oil flow through underflow. The experiment was conducted with several inlet velocities with a constant inlet oil fraction. The usage of the baffle is to induce oil droplet coalescence. Two baffles were used in this experiment : a 1-level baffle and 2-level baffle with a 200 mm height. The baffles induced oil droplet coalescence as the droplets attached on the baffle surface. The coalescence resulted in an increasing droplet size until a point at where the buoyancy forces resulted in detachment of the droplet from the baffle and movement of the droplet upward into the overflow. Thus, the baffles reduced the amount of oil droplets moving downwards into the underflow and increased the watercut in the underflow. It was obtained that the usage of baffles could increase the watercut value in underflow up to 5% at the split-ratio of 5-30% and the maximum value of watercut is almost 100% at split-ratio 60% or more. [ABSTRACT FROM AUTHOR]

This study aims to understand the mechanism of oil-water separation process inside Liquid-Liquid Cylindrical Cyclone (LLCC) and the effect of operating parameters to the separation characteristics. Some experimental runs have been designed and commissioned, then the results from both experiments and visualization data are presented. General characteristics of separation process and flow behavior in the LLCC were explained in the form of qualitative observation and quantitative explanation. For the experimental runs, the LLCC was tested under the wide range of operating parameters such as inlet mixture velocity, split-ratio, and different inlet oil volumetric concentration. The acquired data include overflow oil volume fraction. [ABSTRACT FROM AUTHOR]

The experimental studies on flow pattern of adiabatic gas-liquid two-phase flow in horizontally oriented mini-channel were conducted. The test section was a 1.6 mm inner diameter glass pipe. The range of gas and liquid superficial velocities were 0.025 - 66.3 m/s and 0.033 - 4.935 m/s, respectively. The working fluids were air and glycerol aqua solution in various percentage, 0%, 20%, 40%, and 60% indexed by W, G20, G40, and G60, respectively. The flow pattern data were obtained by analyzing the video images, captured by using the high-speed camera. As a result, it was found that the flow patterns observed in the present study were bubbly, plug, slug-annular, annular, and churn, while the stratified flow was not appeared. In the flow pattern map, the change of liquid viscosity affects to the shift of the transition line between flow pattern, particularly slug-annular to annular and slug-annular and annular to churn flow. [ABSTRACT FROM AUTHOR]

The standing-wave thermoacoustic prime mover is a device to convert heat into work in the form of sound. It is one of the most potential applications for a thermoacoustic prime mover to utilize low-grade heat source to drive a refrigerator or electrodynamic linear alternator. Low efficiency of the device becomes interesting to be studied; it is because of no optimum heat exchange between the channel wall and the working gas that occur in the stack. The stack is the main part of the thermoacoustic prime mover in where the thermoacoustic energy conversion process takes place. The ωτ parameter is regarded as a nondimensional parameter determining the efficiency of the heat exchange in the stack and it depends on the hydraulic radius of the stack. This experiment was carried out by changing the hydraulic radius of the stack to control the value of ωτ. The stack was made of a pile stainless steel wire mesh because it is easier to vary the hydraulic radius than another kind of stack. The length of the resonator is 1.28 m and air at atmospheric pressure is used to fill the resonator as the working gas. Experimental results show that ωτ affecting the onset temperature difference, frequency, pressure amplitude, and acoustic power. Finally, ωτ parameter is a useful property which is needed to be considered to enhance the performance of thermoacoustic prime mover. [ABSTRACT FROM AUTHOR]

This study aims to determine the phenomena of water and oil separation and the performance of the Liquid- Liquid Cylindrical Cyclone (LLCC). The experiments were conducted with water and oil in a transparent LLCC separator that allows the visualization of the mixture. Series of experiments for various of inlet mixture velocity (Vm), inlet oil volume fraction (α), and split-ratio have been performed. Volume fraction of oil in the inlet were 0.06 (6%), 0.1 (10%), and 0.15 (15%). The examined inlet mixture velocity variations were 1.0 m / s, 1.5 m / s, and 2.0 m / s. Splitratio was made in the range 25-70%. The watercut in underflow were the variables measured. The experimental results show that the LLCC was able to separate water and oil and produced free water with concentration up to 98%. By increasing the value of the split-ratio, watercut in underflow increase and reached the optimum point. Optimal split-ratio observed is between 60% and 70% depend on the inlet oil volume fraction. [ABSTRACT FROM AUTHOR]