Papers by Keyword: Velocity

Abstract: Four different riser pipe exit configurations were modelled and the flow across them analysed using STAR CCM+ CFD codes. The analysis was limited to exit configurations because of the length to diameter ratio of riser pipes and the limitations of CFD codes available. Two phase flow analysis of the flow through each of the exit configurations was attempted. The various parameters required for detailed study of the flow were computed. The maximum velocity within the pipe in a two phase flow were determined to 3.42 m/s for an 8 (eight) inch riser pipe. After thorough analysis of the two phase flow regime in each of the individual exit configurations, the third and the fourth exit configurations were seen to have flow properties that ensures easy flow within the production system as well as ensure lower computational cost. Convergence (Iterations), total pressure, static pressure, velocity and pressure drop were used as criteria matrix for selecting ideal riser exit geometry, and the third exit geometry was adjudged the ideal exit geometry of all the geometries. The flow in the third riser exit configuration was modelled as a two phase flow. From the results of the two phase flow analysis, it was concluded that the third riser configuration be used in industrial applications to ensure free flow of crude oil and gas from the oil well during oil production.

Abstract: A simple numerical model has been generated for developing a code of Smoothed Particle Hydrodynamics (SPH) method. Those will be modified and used for future research. In this computational research domain is a square that consists of a real particle and virtual particle as the boundary treatment. In the initial condition, particle occupies a certain position. Circular flow has been generated by a rotating vertical cylinder to produce shear velocity to the real particle. The particles movement has been observed during time integration. A physical model has been constructed to compare the numerical model. The movement of real particles on the numerical model agrees with the movement of water particles on the physical model.

Abstract: The performance of a Plate fin radiator in terms of heat transfer rate and coolant side pressure drop depends significantly on the distribution of coolant through its passages. Uneven flow through the passages i.e. flow maldistribution, can cause local hot spots in the radiator due to high coolant flow in some passages. The flow maldistribution among the passages can be reduced to a large extent by proper optimisation of the header. The present paper investigates the method to optimise the header of a 680 kW radiator to reduce the maldistribution in its passages using Computational Fluid Dynamics (CFD). The analysis was simplified by considering the porous media instead of simulating the exact fin configuration in the radiator. The maximum and absolute values of flow maldistribution factor were considered in this study to determine the effectiveness of the header with respect to flow maldistribution. The flow maldistribution factor was determined based on the individual velocity of coolant in a passage and the average velocity of coolant in all the passages. The methods used for optimisation were rounding the header inlet, tapering the header partially, changing the position of the taper and modifying the end portion of the header. In this paper two parameters, viz., flow maldistribution parameter and absolute maldistribution parameter were considered to measure the maldistribution of a radiator. Due to these optimisations in the header, the maximum and absolute values of maldistribution reduced up to 18% and 45% respectively.

Abstract: Oilwell cementing is part of completing a well prior to production. As a casing is installed after a section of the well is drilled, cement is pumped downhole. Reservoir fluid such as oil which may encroach into the wellbore due to naturally fractured or unconsolidated formation would mix with the cement pumped downhole. Recent studies have shown that the presence of oil affect cement quality to an extent where the cement compressive strength is greatly reduced. Early detection of possible oil contamination into cement may prevent well integrity problem. With intense application of acoustic principle into wellbore, however, not many references available to detect the presence of oil in cement system using this principle. This study investigates whether acoustic waves can detect oil in cement. Class G cement is mixed with both water and brine where crude oil is then added to the mixture. The resulting slurry were cured using High Pressure High Temperature (HPHT) curing chamber at 120°C and 4,000 psi for 24 hours and is then cored into 1-inch cylinder. SonicViewer-SX is used to propagate acoustic waves through the core sample where the transit time is recorded and analyzed. It is found that oil can be detected in cement using acoustic waves since oil-filled samples have slower P-waves and S-waves velocities than cement-filled samples. The case is also proven when water is replaced by brine as the mixing fluid which oil-filled samples have lower P-waves and S-waves velocities to that of cement-filled samples.

Abstract: To increasing the efficiency research a single cylinder linear engine with spring system has been done. Issues raised in the study was the analysis of air flow into the combustion chamber in a single cylinder linear engine, with a spring system for its return cycle. Solidworks has been used to design and simulation as well. This study compared the fluid flow in the combustion chamber between the conventional engine and linear combustion engine. The parameters used are the engine speeds 1000 rpm, 4000 rpm and 4500 rpm. The speeds is chosen because has been predicted that the inlet port on the linear engine can not work properly. Results of analysis that has been done appears average pressure of conventional has a higher value than the linear combustion engine. The same thing happened in velocity, in the average value of the conventional engine is higher than the linear combustion engine.

Abstract: A detailed work based on the second-order ordinary differential equation is presented to solve oscillation in the trajectory projectile motion of cricket ball for damped alternating external force ( ) problems. This paper purpose to compute the distance time depends horizontal and the distance time depends vertical. The parabolic path of trajectories for a projectile motion of cricket ball increase oscillation with the value of parameter and is the storm force.

Abstract: This paper reports on experimental work that has been undertaken to investigate the flexural strength performance of fly ash-based geopolymer (FG) concrete. The FG concrete was prepared using low calcium class F fly ash with high silicate content. The flexural strength properties of FG were assessed using modulus of rupture test up to the age of 360 days. Compressive strength and Ultrasonic Pulse Velocity (UPV) tests were also performed to corroborate the flexural strength test results. The results showed that the FG concrete demonstrates a comparable compressive strength and velocity to OPC concrete. Hewever, the flexural strength of FG concrete exhibited a better performance compared to that OPC concrete. The measured flexural strength of FG concrete also exhibited a higher value compared to the predicted one using ACI 318M-08 standard. The relationship between flexural strength with compressive strength demonstrated a similarity behavior to that OPC concrete. Thus, it can be concluded that the use of the ACI standard can be applied conservatively to determine the flexural strength of fly ash-based geopolymer concrete.

Abstract: The paper deals with stepper motor control using microcontroller ATmega8-16PU. In the paper are mentioned two ways of control, namely full-step mode and half-step mode control. At first, bipolar stepper motor is introduced. Next, there is created measuring stand consisting of bipolar stepper motor with one step angle 1.8° and encoder with 360 CPR. During the experiment were measured angular velocities by I/O measuring card MF624 cooperating with Matlab/Simulink. The results show differences between used two stepping modes of motor.

Abstract: The paper proposes to realize a simulative analysis following the theoretical notions regarding the hydraulic jump, at flow of fluids through open channels, when open a plane penstock, which is located in a trapezoidal channel. A penstock is formed from a plan panel with upright movement in supports, with the possibility of adjustment a fluid flow by means of a handling device.

Abstract: The colloidal borescope can be used for measuring groundwater flow directions and velocity. It is an integrated high-resolution flux gate compass with a high-magnification colloid-imaging camera that can measure flow at selected depths within a well. In this study, the colloidal borescope was used to determine flow direction and measure velocity during a pumping test for the riverbank filtration study in Jenderam Hilir, Selangor. During each measurement, the instrument, which monitored the movement of the suspended particles, was inserted into a well at a particular depth (screen well). The relative flow direction was determined by plotting the trajectory and speed of colloidal particles across the screen with AquaLITE Software, which determined the horizontal speed of the particles and flow speed. The groundwater flow pattern was dtermined at four boreholes in the study area, and the groundwater flow velocities were found ranging from 0.72 to 2.45 x (10^-4) m/s. The direction of the groundwater flow at boreholes monitoring well 02 (MW02) and monitoring well 19 (MW19) was moved toward borehole pumping well (PW). The groundwater flow at monitoring well 01 (MW01) was moving toward the northwest of the study site which was parallel with the Langat river. The groundwater flow in borehole monitoring well A (MWA) was toward the southern part of the study site and was not affected by the pumping test activities at borehole monitoring well 03 (MW03).