ANALISIS LAJU ALIRAN MASSA FLUIDA DINGIN TERHADAP EFEKTIVITAS PENUKAR KALOR SHELL AND TUBE DESTILLASI MINYAK ATSIRI CENGKEH (Syzygium aromaticum)

Shell and tube type heat exchanger is a component of clove essential oil distillation apparatus using hot steam as hot fluid and water as a cold fluid, each flowing in opposite directions. The distillation system in the field still uses a condenser or straight pipe heat exchanger, where the temperature of the hot fluid that comes out is still considered high enough so that the indication of effectiveness is not optimal. To optimize the effectiveness, a shell and tube heat exchanger is designed with a numerical method based on Fluent CFD using a hexagonal pipe geometry in tube layouts of 30°, 60°, 45°, and 90° inline and staggered arrangement and counter flow type. This study varied the cold mass flow rate (ṁc) = 0.052; 0.059; 0.083; 0.1; 0.12 Kg/s, while the mass flow rate of the hot fluid is constant. The simulation results obtained that the maximum effectiveness occurred at a mass flow rate of 0.052 kg/s of 5.45% staggered layout and the minimum occurred at a mass flow rate of 0.12 kg/s of 4.01% on an inline layout. The results of this research are also expected to help the community which can be used for various essential oils.

Particle behavior in a turbulent flow within an axially corrugated geometry

In this numerical study particle behavior inside a sinusoidal pipe geometry is analyzed. The 3D geometry consists of three identical modules, with a periodic boundary condition applied to the flow in the stream wise direction. The incompressible, turbulent gas flow is modeled using a Large Eddy Simulation (LES) approach. Furthermore, the particle dynamics are simulated using a Lagrangian point force approach incorporating the Stokes drag and slip correction factor. Four different sizes of particles, corresponding to a Stokes number less than unity, are considered along with two different inflow conditions: continuous and pulsatile. The pulsatile inflow has an associated flow frequency of 80 Hz. The fluid flow through the sinusoidal pipe is characterized by weak flow separation in the expansion zones of the sinusoidal pipe geometry, where induced shear layers and weak recirculation zones are identified. Particle behavior under the two inflow conditions is quantified using particle dispersion, particle residence time, and average radial position of the particle. No discernible difference in the particle behavior is observed between the two inflow conditions. As the observed recirculation zones are weak, the particles are not retained within the cavities for a long duration of time, thereby reducing their likelihood of agglomerating.

Laser Scanning and Parametrization of Weld Grooves with Reflective Surfaces

This paper presents a novel weld groove parametrization algorithm, which is developed specifically for weld grooves in typical stub and butt joints between large tubular elements. The procedure is based on random sample consensus (RANSAC) with additionally proposed correction steps, including a corner correction step for grooves with narrow root weld, and an iterative error elimination step for improving the initially obtained data fit. The problem of curved groove sides (due to the pipe geometry) is attributed and solved. In addition, the procedure detects and eliminates several types of data noise due to laser line reflections. The performance of the procedure is studied experimentally using small-scale test objects, which have been ground using typical industrial power tools to achieve a realistic level of reflections. The execution times and data fit errors of the proposed procedure are compared to a procedure based on a more conventional RANSAC approach for line segment detection.

Research of Spherical Capsule Feeding System in Hydraulic Pipelines

Feeding the material to be transported in the hydraulic pipelines to the system is a subject open to research. The shape, size and density of the material gain importance in the selection of feeding systems. Finding the pressure drops that occur in the flow of spherical ice capsules with water is the basis of the research. However, before the measurements were made, preliminary research was carried out on feeding the capsules to the system during the installation of the experimental set-up. In the experimental study with solid particles with the diameter ratios (0.8) and densities (960 kg/m3) with smaller dimensions (d=0.014m), a pipe construction was obtained in which the solid particles are easily fed into the hydraulic pipeline. Experimental study revealed that lower than predicted pressures occur at the point where solid particles are fed into the pipe. This result means a greater pressure drop than the pressure drops obtained in the venturimeter zone with the same diameter ratio. In this article includes a step-by-step method and a sample pipe geometry for studies that require a low pressure zone in hydraulic pipelines. The pipe geometry designed in this study will form a model for the supply systems in the pipelines. The low pressure region is provided with a pipe and flow arrangement without consuming energy.

Perspective on the Response of Turbulent Pipe Flows to Strong Perturbations

Pipe flow responds to strong perturbations in ways that are fundamentally different from the response exhibited by boundary layers undergoing a similar perturbation, primarily because of the confinement offered by the pipe wall, and the need to satisfy continuity. We review such differences by examining previous literature, with a particular focus on the response of pipe flow to three different kinds of disturbances: the abrupt change in surface condition from rough to smooth, the obstruction due to presence of a single square bar roughness elements of different sizes, and the flow downstream of a streamlined body-of-revolution placed on the centerline of the pipe. In each case, the initial response is strongly influenced by the pipe geometry, but far downstream all three flows display a common feature, which is the very slow, second-order recovery that can be explained using a model based on the Reynolds stress equations. Some future directions for research are also given.

Enhancing Acoustic Emission Characteristics in Pipe-Like Structures with Gradient-Index Phononic Crystal Lens

Phononic crystals have the ability to manipulate the propagation of elastic waves in solids by generating unique dispersion characteristics. They can modify the conventional behavior of wave spreading in isotropic materials, known as attenuation, which negatively influences the ability of acoustic emission method to detect active defects in long-range, pipe-like structures. In this study, pipe geometry is reconfigured by adding gradient-index (GRIN) phononic crystal lens to improve the propagation distance of waves released by active defects such as crack growth and leak. The sensing element is designed to form a ring around the pipe circumference to capture the plane wave with the improved amplitude. The GRIN lens is designed by a special gradient-index profile with varying height stubs adhesively bonded to the pipe surface. The performance of GRIN lens for improving the amplitude of localized sources is demonstrated with finite element numerical model using multiphysics software. Experiments are conducted using pencil lead break simulating crack growth, as well as an orifice with pressured pipe simulating leak. The amplitude of the burst-type signal approximately doubles on average, validating the numerical findings. Hence, the axial distance between sensors can be increased proportionally in the passive sensing of defects in pipe-like geometries.

Enhancing cavitation intensity in co-flow water cavitation peening with organ pipe nozzles

Co-flow water cavitating jets induce compressive residual stress through cavitation impacts produced by the collapse of the cavitation cloud. Co-flow water cavitation peening causes minimal surface alteration compared to conventional processes such as shot peening, which is a major advantage. However, enhancement of cavitation intensity for co-flow water cavitation peening nozzles is required for practical applications requiring greater process capability. Scaling of co-flow cavitation peening nozzles to achieve greater cavitation intensity requires higher flow rates, thus requiring pumps of higher capacities. In contrast, organ pipe geometry nozzles can enhance cavitation intensity without significant increase in pump capacity and have been used in deep sea drilling applications. The objective of this work is to study the effects of organ pipe inner jet nozzle geometry on co-flow water cavitation intensity and peening performance relative to a standard (unexcited) inner jet nozzle geometry through experiments on aluminum alloy Al 7075-T651. Nozzle performance is characterized via extended mass loss and strip curvature tests, high-speed visualization of the cavitation cloud, analysis of impulse pressures, and through-thickness residual stress measurements. It is found that the optimum organ pipe inner jet nozzle geometry enhances the mass loss and peak strip curvature by 61% and 66%, respectively, compared to the unexcited inner jet nozzle. Residual stress measurements show that the organ pipe inner jet nozzle produces deeper compressive residual stresses in the material than the unexcited inner jet nozzle.

Field measurements on a large natural sand boil along the river Po (Italy)

Sand boils are the surface manifestation of an erosion process, known as backward erosion piping, which may take place beneath river embankments during high-water events. The risk of embankment failure greatly increases in locations affected by sand boils. Numerous studies have been carried out, mainly at the laboratory scale, providing significant advancements in this field. Nonetheless, there is still a gap between research and practice that needs to be filled.This study presents a set of field measurements carried out on a large sand boil reactivated near the toe of an embankment along the river Po (Italy). Hydraulic heads, velocity and discharge, concentration and pipe geometry were measured as a function of the water level in the river during the November 2018 flood. The collected data are compared to predictions of a theoretical model which provides the head loss in the vertical pipe. Furthermore, the local exit gradients, as deduced from measurements, are discussed, together with the operational critical gradients adopted in current design practice.The collected data provide important input parameters for the calibration of analytical and numerical models, typically implemented to investigate the sand boil evolution and then to assess the backward erosion piping risk at real scale.

Dent Screening Criteria Based on Dent Restraint, Pipe Geometry and Operating Pressure

A safety advisory (2010-01), issued by the National Energy Board (NEB) in June 2010, referenced two incidents which were a result of a fatigue crack failure that occurred within shallow dents [1]. The dents in both instances were less than 6% (of the OD). Currently, there is no consensus on how shallow dents or shallow dents with stress concentrators, as called by the ILI tool, are assessed and acted upon. BMT Canada Ltd. (BMT) was contracted by the Canadian Energy Pipeline Association (CEPA) to develop a definition for shallow dents, and two levels of screening method for the integrity assessment of shallow restrained dents and unrestrained dents. These two levels are known as CEPA Level 0 and CEPA Level 0.5 dent integrity assessment techniques that may be applied without finite element modelling or detailed calculations. The BMT dent assessment finite element (FE) modeling method was used to develop an extensive database of dents for different pipe geometries (OD/t), indenter shapes, pipe grades, and indentation depths. The results of the FE modelling were used to develop trends for the stress magnification factors (KM) across the range of pipes and dents modelled. These trends are used as the basis for the Level 0 and Level 0.5 dent screening and assessment approaches that can be used for both unrestrained dents and shallow restrained dents. The results show that for low OD/t pipe geometry and/or low spectrum severity indicator (SSI) [2] dent fatigue life may not pose an integrity threat. These dent screening approached have been adopted in the API Recommended Practice 1183 Dent Assessment and Management, that is currently under development.