Optimisation of a Side Inlet for H2 Entry into an Ultrasonic Spray Pyrolysis Device

An ultrasonic spray pyrolysis (USP) device consists of an evaporation and two reaction zones of equal length, into which an aerosol with a precursor compound enters, and where nanoparticles are formed in the final stage. As part of this research, we simulated the geometry of a side inlet, where the reaction gas (H2) enters into the reaction tube of the device by using numerical methods. Mixing with the carrier gas (N2) occurs at the entry of the H2. In the initial part, we performed a theoretical calculation with a numerical simulation using ANSYS CFX, while the geometries of the basic and studied models were prepared with Solidworks. The inlet geometry of the H2 included a study of the position and radius of the inlet with respect to the reaction tube of the USP device, as well as a study of the angle and diameter of the inlet. In the simulation, we chose the typical flows of both gases (N2, H2) in the range of 5 L/min to 15 L/min. The results show that the best geometry is with the H2 side inlet at the bottom, which the existing USP device does not allow for. Subsequently, temperature was included in the numerical simulation of the basic geometry with selected gas flows; 150 °C was considered in the evaporation zone and 400 °C was considered in the other two zones—as is the case for Au nanoparticle synthesis. In the final part, we performed an experiment on a USP device by selecting for the input parameters those that, theoretically, were the most appropriate—a constant flow of H2 5 L/min and three different N2 flows (5 L/min, 10 L/min, and 15 L/min). The results of this study show that numerical simulations are a suitable tool for studying the H2 flow in a UPS device, as the obtained results are comparable to the results of experimental tests that showed that an increased flow of N2 can prevent the backflow of H2 effectively, and that a redesign of the inlet geometry is needed to ensure proper mixing. Thus, numerical simulations using the ANSYS CFX package can be used to evaluate the optimal geometry for an H2 side inlet properly, so as to reconstruct the current and improve future USP devices.

Using a Deflector and Crest Design to Make a Safe Spillway Operation

Floods are an important hazard throughout the world. The origins of some floods are a dam failure, hydraulic structure failure as well as an improper performance of the spillway. Among these, shaft spillways are known as a flood drainage system in dams, which is submerged by increasing the level of the reservoir, so that reduces the spillway efficiency and causes over topping. Investigations show that using deflector and aeration in shaft spillways will cause the flow pattern to improve. In this study, it has been tried to experiment on the impact of a deflector located in the throat and inlet geometry of the crest on the improvement of the hydraulic performance of the shaft spillway, and decrease to some extent the hazard induced by lack of timely drainage of floods in dam reservoirs. In order to investigate the deflector effect, three constriction specimens in shaft throat with constriction area to shaft area ratio (Ad/Ai) of respectively 0.75, 0.5 and 0.25 were considered as scenarios. In each scenario, the conditions of the flow passing through 12 different specimens of spillway with Crown Wheel inlets were tested and the results were compared with the flow conditions in crown wheel spillways without deflector (reference model). The results showed that the use of deflector has an important role in reducing vortex flows and stabilizing changes in the water level of the reservoir, and also increases the discharge coefficient of the flow. The studies on reference models also showed that Crown Wheel inlets (C.W.) improved shaft spillway performance, with C.W. spillways having an average discharge coefficient of 32% higher than shaft spillways. Finally, considering optimal deflector factors and C.W. geometry, an optimal model was proposed for flood reservoir conditions.

ARBITRARY GENERATION OF VERY LONG, AND TSUNAMI-LIKE WAVES USING AN OPTIMZED PUMP-DRIVEN METHOD

Tsunami remain a focal point of coastal engineering research, particularly when interacting with near-shore bathymetry and coastal developments. A recent push in experimentation involving long waves has led to novel methods, to generate and accurately control long waves in laboratories. This work showcases a recent implementation of a pump-driven long wave generation, with novel control strategies, an optimized inlet geometry, and an extra-wide and uniquely long propagation flume with the overall aim to provide the latest insight into experimental long wave generation.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/ZR0r88i2ev0

Effect of Axial Casing Groove Geometry on Rotor-Groove Interactions in the Tip Region of a Compressor

The present experimental study expands an ongoing effort to characterize the interactions of axial casing grooves (ACGs) with the flow in the tip region of an axial turbomachine. In recent work, we have tested a series of grooves with the same inlet geometry that overlaps with the rotor blade leading edge, but with different exit directions. Two geometries have stood out: The U grooves, which have an outflow in the negative circumferential direction (opposing the blade motion) are the most effective in suppressing stall, achieving as much as 60% reduction in stall flowrate, but cause a 2% decrease in efficiency around the best efficiency point (BEP). In contrast, the S grooves, which have an outflow in the positive circumferential direction, achieve a milder improvement in stall suppression (36%) but do not degrade the performance near BEP. This paper focuses on explaining these trends by measuring the flow in the tip region and within the U and S grooves. The stereo-PIV (SPIV) measurements are performed in the JHU refractive index matched facility, which allows unobstructed observations in the entire machine. Data has been acquired in two meridional planes that intersect with the grooves at different locations, and two radial planes (z, θ), the first coinciding with the blade tip, and the second, with the tip gap. For each plane, data has been acquired at fourteen rotor orientations relative to the grooves to examine the rotor-grooves interactions. At low flow rates, the inflow into both grooves peaks periodically when the blade pressure side (PS) faces the entrance (downstream side) to the grooves. This inflow rolls up into a large vortex that remains and lingers within the groove long after the blade clears the groove. The outflow depends on the shape of the groove. For the S groove, the outflow exits at the upstream end of the groove in the positive circumferential direction, as designed. In contrast, for the U grooves, the fast radially and circumferentially negative outflow peaks at the base of the U. The resulting jet causes substantial periodic variations in the flow angle near the leading edge of the rotor blade. Close to the BEP, the chordwise location of primary blade loading moves downstream, as expected. The inflow into the grooves occurs for a small fraction of the blade passing period, and most of the tip leakage vortex remains in the main flow passage. For the S grooves, the rotor-groove interactions seem to be minimal, with little (but not zero) inflow or outflow at both ends, and minimal changes to the flow angle in the passage. In contrast, for the U groove, the inflow into and outflow from the groove reverse direction (compared to the low flowrate trends), entering at the base of the U, and exiting mostly at its downstream end, especially when the blade is not near. The resulting entrainment of secondary flows from the groove into the passage are likely contributors to the reduced efficiency at BEP for the U grooves.

Liquid-Cooling System of an Aircraft Compression Ignition Engine: A CFD Analysis

The present work deals with an analysis of the cooling system for a two-stroke aircraft engine with compression ignition. This analysis is carried out by means of a 3D finite-volume RANS equations solver with k- ϵ closure. Three different cooling system geometries are critically compared with a discussion on the capabilities and limitations of each technical solution. A first configuration of such a system is considered and analyzed by evaluating the pressure loss across the system as a function of the inlet mass-flow rate. Moreover, the velocity and vorticity patterns are analyzed to highlight the features of the flow structure. Thermal effects on the engine structure are also taken into account and the cooling system performance is assessed as a function of both the inlet mass-flow rate and the cylinder jackets temperatures. Then, by considering the main thermo-fluid dynamics features obtained in the case of the first configuration, two geometrical modifications are proposed to improve the efficiency of the system. As regards the first modification, the fluid intake is split in two manifolds by keeping the same total mass-flow rate. As regards the second configuration, a new single-inlet geometry is designed by inserting restrictions and enlargements within the cooling system to constrain the coolant flow through the cylinder jackets and by moving downstream the outflow section. It is shown that the second geometry modification achieves the best performances by improving the overall transferred heat of about 20% with respect to the first one, while keeping the three cylinders only slightly unevenly cooled. However, an increase of the flow characteristic loads occurs due to the geometrical restrictions and enlargements of the cooling system.

Experimental study of circular inlets effect on the performances of Gas-Liquid Cylindrical Cyclone separators (GLCC)

The gas-liquid cylindrical cyclone (GLCC) separators is a fairly new technology for the oil and gas industry. The current GLCC separator, a potential alternative for the conventional one, was studied, developed, and patented by Chevron company and Tulsa University (USA). It is used for replacing the traditional separators that have been used over the last 100 years. In addition, it is significantly attracted to petroleum companies in recent years because of the effect of the oil world price. However, the behavior of phases in the instrument is very rapid, complex, and unsteady, which may cause the difficulty of enhancing the performance of the separation phases. The multiple recent research shows that the inlet geometry is probably the most critical element that influences directly to the performance of separation of phases. Though, so far, most of the studies of GLCC separator were limited with the one inlet model. The main target of the current study is to deeply understand the effect of different geometrical configurations of the circular inlet on performances of GLCC by the experimental method for two phases flow (gas-liquid). Two different inlet configurations are constructed, namely: One circular inlet and two symmetric circular inlets. As a result, we propose the use of two symmetric circular inlets to enhance separator efficiency because of their effects.

Evaluation of variable pitot inlet concepts for transonic and supersonic civil aviation

Purpose This paper aims to describe the selection of the ideal variable inlet concept group by using results of aerodynamic investigations, system safety analyses and integration studies. Design/methodology/approach Aerodynamic and functional inlet requirements are explained and variable inlet concept groups are introduced. The concept evaluation by means of a weighted point rating is presented. The respective concept groups are analysed and evaluated regarding economic, functional and safety requirements. Findings By means of this evaluation, the concept group that adjusts the inlet geometry by rigid segment repositioning is identified as most suitable concept group. Originality/value The early selection of the most suitable concept group enables more detailed subsequent concept investigations, potentially enabling the technology of variable inlets for future commercial aircraft.

Influence of Inlet Geometry on the Efficiency of 1 MW Steam Turbine

The process of the design of the 1 MW steam turbine includes designing the stator and rotor blades, the steam turbine inlet and exit, the casing and the rotor. A turbine that operates at rotation speeds other than 3000 rpm requires a gearbox and generator with complex electronic software. This article analyses the efficiency of eight turbine variants, including seven inlet geometries and three stages of stator as well as an eight variant with one of the inlets, all three stages and an outlet.This article analyses the efficiency of 8 turbine variants, including four spiral inlet geometries and tree stages in a 1 MW steam turbine. In the article, inlets and 1st stator blades of various geometries were analysed to obtain maximal turbine efficiency. Changing the inlet spiral from one pipe to two pipes increased the turbine efficiency. The geometry of the blades and turbine inlets and outlet was carried out using Design Modeller. The blade mesh was prepared in TurboGrid and inlet in ANSYS Meshing.