scholarly journals Low-pressure nozzle with aerodynamic fuel atomization

2020 ◽  
Vol 65 (3) ◽  
pp. 357-364
Author(s):  
S. S. Tihonchik ◽  
N. I. Puchko
Keyword(s):  
Gas Turbine ◽  
Flow Rate ◽  
Flow Simulation ◽  
Internal Flow ◽  
Maximum Flow ◽  
Low Pressure ◽  
Computer Design ◽  
Fuel Atomization ◽  
Stage Of Development ◽  
Pressure Nozzle

A research was carried out with the construction of a model of a low-pressure nozzle with aerodynamic fuel atomization, which shows the advantages of nozzles of this type. In order to reduce the time at the stage of development and calculations, modern computer design systems were used. The research was carried out in the Flow Simulation module of the SolidWorks software package, which allows you to calculate and build a model of the internal flow around the nozzle using already known parameters. These parameters were set through the program conditions panel: fuel consumption per second; air flow rate at the inlet to the nozzle; static pressure in the combustion chamber. The calculations performed by the module made it possible to evaluate the manufacturability of the design, as well as the internal processes of mixing fuel with air. To determine the quality of fine dispersion of the fuel atomization, a model of the velocity field was calculated over the entire section of the nozzle, from which it can be seen that the maximum flow rate of the fuel is achieved in the outlet channels of the fuel atomizer of the nozzle. The results obtained indicate the operation of the low-pressure principle while maintaining high-quality fuel atomization. The use of low-pressure nozzle with aerodynamic fuel atomization is possible in modern gas turbine engines of civil aircraft, as well as in gas turbine.

Comprehensive Fall Velocity Study on Continuous Flow Plungers

2021 ◽  
pp. 1-20
Author(s):  
Ozan Sayman ◽  
Eduardo Pereyra ◽  
Cem Sarica
Keyword(s):  
Drag Coefficient ◽  
Flow Rate ◽  
Continuous Flow ◽  
Gas Flow ◽  
Flow Simulation ◽  
Maximum Flow ◽  
Wall Effect ◽  
Liquid Holdup ◽  
Fall Velocity ◽  
Influential Parameters

Summary The objective of this study is the experimental and theoretical investigation of the fall mechanics of continuous flow plungers. Fall velocity of the two-piece plungers with different sleeve and ball combinations and bypass plungers are examined in both static and dynamic conditions to develop a drag coefficient relationship. The dimensionless analysis conducted included the wall effect, inclination, and the liquid holdup correction of the fall stage. A fall model is developed to estimate fall velocities of the ball, sleeve, and bypass plungers. Sensitivity analysis is performed to reveal influential parameters to the fall velocity of continuous flow plungers. In a static facility, four sleeves with different height, weight, and outer diameter (OD); three balls made with different materials; and a bypass plunger are tested in four different mediums. The wall effect on the settling velocity is defined, and it is used to validate the ball drag coefficient results obtained from the experimental setup. Two-phase flow experiments were conducted by injecting gas into the static liquid column, and the liquid holdup effect on the drag coefficient is observed. Experiments in a dynamic facility are used for liquid holdup and deviation corrections. The fall model is developed to estimate fall velocities of the continuous flow plungers against the flow. Dimensionless parameters obtained in the experiments are combined with multiphase flow simulation to estimate the fall velocity of plungers in the field scale. Reference drag coefficient values of plungers are obtained for respective Reynolds number values. Experimental wall effect, liquid holdup, and inclination corrections are provided. The fall model results for separation time, fall velocity, total fall duration, and maximum flow rate to fall against are estimated for different cases. Sensitivity analysis showed that the drag coefficient, the weight of plungers, pressure, and gas flow rate are the most influential parameters for the fall velocity of the plungers. Furthermore, the fall model revealed that plungers fall slowest at the wellhead conditions for the range of gas flow rates experienced in field conditions. Lower pressure at the wellhead had two opposing effects; namely, reduced gas density, thereby reducing the drag and gas expansion that increased the gas velocity, which in turn increased the drag. Estimating fall velocity of continuous flow plungers is crucial to optimize ball and sleeve separation time, plunger selection, and the gas injection rate for plunger-assisted gas lift (PAGL). The fall model provides maximum flow rate to fall against, which is defined as the upper operational boundary for continuous flow plungers. This study presents a new methodology to predict fall velocity using the drag coefficient vs. Reynolds number relationship, wall effect, liquid holdup, deviation corrections, and incorporating multiphase flow simulation.

scholarly journals DNA Printing Integrated Multiplexer Driver Microelectronic Mechanical System Head (IDMH) and Microfluidic Flow Estimation

Micromachines ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 25
Author(s):  
Jian-Chiun Liou ◽  
Chih-Wei Peng ◽  
Philippe Basset ◽  
Zhen-Xi Chen
Keyword(s):  
Mechanical System ◽  
Flow Rate ◽  
Pulse Width ◽  
Flow Distribution ◽  
Internal Flow ◽  
Maximum Flow ◽  
Maximum Flow Rate ◽  
Driving Voltage ◽  
Generation Process ◽  
Injection Nozzle

The system designed in this study involves a three-dimensional (3D) microelectronic mechanical system chip structure using DNA printing technology. We employed diverse diameters and cavity thickness for the heater. DNA beads were placed in this rapid array, and the spray flow rate was assessed. Because DNA cannot be obtained easily, rapidly deploying DNA while estimating the total amount of DNA being sprayed is imperative. DNA printings were collected in a multiplexer driver microelectronic mechanical system head, and microflow estimation was conducted. Flow-3D was used to simulate the internal flow field and flow distribution of the 3D spray room. The simulation was used to calculate the time and pressure required to generate heat bubbles as well as the corresponding mean outlet speed of the fluid. The “outlet speed status” function in Flow-3D was used as a power source for simulating the ejection of fluid by the chip nozzle. The actual chip generation process was measured, and the starting voltage curve was analyzed. Finally, experiments on flow rate were conducted, and the results were discussed. The density of the injection nozzle was 50, the size of the heater was 105 μm × 105 μm, and the size of the injection nozzle hole was 80 μm. The maximum flow rate was limited to approximately 3.5 cc. The maximum flow rate per minute required a power between 3.5 W and 4.5 W. The number of injection nozzles was multiplied by 100. On chips with enlarged injection nozzle density, experiments were conducted under a fixed driving voltage of 25 V. The flow curve obtained from various pulse widths and operating frequencies was observed. The operating frequency was 2 KHz, and the pulse width was 4 μs. At a pulse width of 5 μs and within the power range of 4.3–5.7 W, the monomer was injected at a flow rate of 5.5 cc/min. The results of this study may be applied to estimate the flow rate and the total amount of the ejection liquid of a DNA liquid.

Thermal Performance of High-Flow Single-Phase Liquid-Cooled Heat Sinks

2012 ◽  
Author(s):  
Ildar F. Akhmadullin ◽  
Randall D. Manteufel ◽  
Christopher Greene
Keyword(s):  
Thermal Resistance ◽  
Flow Rate ◽  
Heat Sink ◽  
Heat Removal ◽  
Internal Flow ◽  
Maximum Flow ◽  
High Flow ◽  
Repeated Measurements ◽  
Heat Sinks ◽  
Flow Rates

Experimental measurements are reported for high-flow liquid-cooled heat sinks designed for cooling electronics components such as a CPU. The flow rate is up to 2 GPM with internal flow passage length scales on the order of 0.1 to 1.0 mm in the primary heat transfer region. Of the designs tested, three achieved maximum flow rates with pressure drops of less than 1.5 psi. Two have lower maximum flow rates because of higher internal flow resistance. In the experiments, particular attention is given to sources of experimental uncertainty and the propagation of uncertainty through the calculations to reported thermal resistance, R (°C/W). Analysis includes bias and precision errors for direct measurement of temperature, flow rate, and pressure drop. Additionally, a separate thermocouple calibration test is reported to establish measurement uncertainties for the system. Main emphasis is made to the error propagation in thermal resistance calculations of each heat sink and measurement of heat removal rate from the CPU. Data is used to determine the standard error for R which ranges up to about 0.05 °C/W with the maximum for one heat sink up to 0.07 °C/W. Averaging of repeated measurements at the same flow rate without accounting for the range of the original data will result in lower uncertainties in the reported results.

scholarly journals Experimental validation of theoretical calculation and numerical simulation for optimization of divers’s breathing apparatus

2018 ◽  
Vol 23 (1) ◽  
pp. 53-59
Author(s):  
Tamara Stanciu ◽  
Andrei Scupi ◽  
Dumitru Dinu
Keyword(s):  
Numerical Simulation ◽  
Theoretical Calculation ◽  
Flow Rate ◽  
Gas Flow ◽  
Experimental Testing ◽  
Volume Flow Rate ◽  
Flow Simulation ◽  
Maximum Flow ◽  
Open Circuit ◽  
Breathing Apparatus

Abstract In order to optimize the breathing apparatus in the open circuit for divers, theoretical calculus and numerical simulation of resistances specific to the potential flow of gas through the studied circuit were made. Respiratory gas flow simulation through three constructive versions of the second stage pressure reducer intake mechanism was done after modeling the respiratory air circuit through the two main restrictors: the first variable (between the seat and the piston) and the second fixed (the hole in the cylindrical piston). The results regarding the theoretical calculation and numerical simulation have been validated by experimental testing of two of the studied models. Experimental measurements were made on a tester at the Diving Center of Constanta's Hyperbaric Laboratory. The volume flow rate of supplied respiratory gas was recorded, together with the inspire depression that opens the mechanism, until the maximum flow rate for each constructive version. After validating the results of the theoretical calculation and numerical simulation on the two models, the conclusion is the same: the resistance decreases if the geometry of the cylindrical hole in the piston (the second fixed restrictor) changes in a conical hole

A Study on Back Flow Structure in a 2-Bladed Helical Inducer at a Partial Flow Rate

2009 ◽  
Author(s):  
Satoshi Watanabe ◽  
Naoki Inoue ◽  
Koichi Ishizaka ◽  
Akinori Furukawa ◽  
Jun-Ho Kim
Keyword(s):  
Flow Field ◽  
Flow Rate ◽  
Flow Simulation ◽  
Internal Flow ◽  
Back Flow ◽  
Rate Region ◽  
Numerical Studies ◽  
The Difference ◽  
Throat Section ◽  
Suction Performance

The attachment of inducer upstream of main impeller is an effective method to improve the suction performance of turbopump. However, various types of cavitation instabilities are known to occur even at the designed flow rate as well as in the partial flow rate region. The cavitation surge occurring at partial flow rates is known to be strongly associated with the inlet back flow. In the present study, in order to understand the detailed structure of internal flow of inducer, we firstly carried out the experimental and numerical studies of non-cavitating flow, focusing on the flow field near the inlet throat section and inside the blade passage of a two bladed inducer at a partial flow rate. The steady flow simulation with cavitation model was also made to investigate the difference of the flow field between in the cavitating and non-cavitating conditions.

Outcome of Buccal Mucosal Graft Urethroplasty in Long Segment Anterior Urethral Stricture

2020 ◽  
Vol 19 (2) ◽  
pp. 64-68
Author(s):  
Mrinmoy Biswas ◽  
Sudip Das Gupta ◽  
Mohammed Mizanur Rahman ◽  
Sharif Mohammad Wasimuddin
Keyword(s):  
Urethral Stricture ◽  
Flow Rate ◽  
Surgical Outcome ◽  
Simple Technique ◽  
Anterior Segment ◽  
Maximum Flow ◽  
Anastomotic Site ◽  
Buccal Mucosal Graft ◽  
Male Patients

Objective: To assess the success of BMG urethroplasty in long segment anterior urethral stricture. Method: From January 2014 to December 2015, twenty male patients with long anterior segment urethral stricture were managed by BMG urethroplasty. After voiding trial they were followed up at 3 month with Uroflowmetry, RGU & MCU and PVR measurement by USG. Patients were further followed up with Uroflowmetry and PVR at 6 months interval.Successful outcome was defined as normal voiding with a maximum flow rate >15ml /sec and PVR<50 ml with consideration of maximum one attempt of OIU after catheter removal. Results: Mean stricture length was 5.2 cm (range 3-9 cm) and mean follow-up was 15.55 months (range 6-23 months). Only two patients developed stricture at proximal anastomotic site during follow-up. One of them voided normally after single attempt of OIU. Other one required second attempt of OIU and was considered as failure (5%). Conclusion: BMG urethroplasty is a simple technique with good surgical outcome. Bangladesh Journal of Urology, Vol. 19, No. 2, July 2016 p.64-68

Research on an axial-mounted dual magnetostrictive material rods-based electro-hydrostatic actuator

2021 ◽  
pp. 1045389X2110145
Author(s):  
Yuchuan Zhu ◽  
Chang Liu ◽  
Yunze Song ◽  
Long Chen ◽  
Yulei Jiang ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Flow Rate ◽  
Flow Distribution ◽  
Maximum Flow ◽  
Magnetostrictive Material ◽  
Simulation Techniques ◽  
Motion State ◽  
New Type ◽  
Output Characteristics ◽  
Active Rectification

In this paper, an electro-hydrostatic actuator driven by dual axial-mounted magnetostrictive material rods-based pumps (MMPs) with a new type of active rectification valve is designed in the current study. Based on flow distribution of the active rectification valve and driving energy provided by two MMPs, the actuator can output continuous and bidirectional displacement. By establishing a mathematical model of the actuating system, using simulation techniques, the change rule of hydraulic cylinder’s motion state caused by different driving signals are studied and analyzed. Test equipment platform is constructed in the laboratory to test the output characteristics and confirm the feasibility of the new concept. The experimental results indicate that the maximum flow rate can reach approximately 2.7 L·min−1, while the operating frequency is 180 Hz.

Numerical investigation of non-uniform flow in twin-silo combustors and impact on axial turbine stage performance

2021 ◽  
pp. 095765092199394
Author(s):  
Hafiz M Hassan ◽  
Adeel Javed ◽  
Asif H Khoja ◽  
Majid Ali ◽  
Muhammad B Sajid
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Internal Flow ◽  
Large Temperature ◽  
Clear Understanding ◽  
Gas Temperature ◽  
Turbine Stage ◽  
Flow Angle ◽  
Axial Turbine ◽  
Stage Performance

A clear understanding of the flow characteristics in the older generation of industrial gas turbines operating with silo combustors is important for potential upgrades. Non-uniformities in the form of circumferential and radial variations in internal flow properties can have a significant impact on the gas turbine stage performance and durability. This paper presents a comprehensive study of the underlying internal flow features involved in the advent of non-uniformities from twin-silo combustors and their propagation through a single axial turbine stage of the Siemens v94.2 industrial gas turbine. Results indicate the formation of strong vortical structures alongside large temperature, pressure, velocity, and flow angle deviations that are mostly located in the top and bottom sections of the turbine stage caused by the excessive flow turning in the upstream tandem silo combustors. A favorable validation of the simulated exhaust gas temperature (EGT) profile is also achieved via comparison with the measured data. A drop in isentropic efficiency and power output equivalent to 2.28% points and 2.1 MW, respectively is observed at baseload compared to an ideal straight hot gas path reference case. Furthermore, the analysis of internal flow topography identifies the underperforming turbine blading due to the upstream non-uniformities. The findings not only have implications for the turbine aerothermodynamic design, but also the combustor layout from a repowering perspective.

scholarly journals On the Scope of Lagrangian Vortex Methods for Two-Dimensional Flow Simulations and the POD Technique Application for Data Storing and Analyzing

Entropy ◽  
2021 ◽  
Vol 23 (1) ◽  
pp. 118
Author(s):  
Kseniia Kuzmina ◽  
Ilia Marchevsky ◽  
Irina Soldatova ◽  
Yulia Izmailova
Keyword(s):  
Flow Simulation ◽  
Internal Flow ◽  
Reynolds Numbers ◽  
Circular Cylinders ◽  
Vortex Methods ◽  
Flow Simulations ◽  
Additional Information ◽  
Two Dimensional Flow ◽  
Different Shapes ◽  
Problem Formulations

The possibilities of applying the pure Lagrangian vortex methods of computational fluid dynamics to viscous incompressible flow simulations are considered in relation to various problem formulations. The modification of vortex methods—the Viscous Vortex Domain method—is used which is implemented in the VM2D code developed by the authors. Problems of flow simulation around airfoils with different shapes at various Reynolds numbers are considered: the Blasius problem, the flow around circular cylinders at different Reynolds numbers, the flow around a wing airfoil at the Reynolds numbers 104 and 105, the flow around two closely spaced circular cylinders and the flow around rectangular airfoils with a different chord to the thickness ratio. In addition, the problem of the internal flow modeling in the channel with a backward-facing step is considered. To store the results of the calculations, the POD technique is used, which, in addition, allows one to investigate the structure of the flow and obtain some additional information about the properties of flow regimes.

scholarly journals Research on the impact of ship traffic flow on the restricted channel segment of the middle Yangtze River based on traffic wave theory

2021 ◽  
Vol 3 (8) ◽  
Author(s):  
Ting Liu ◽  
Gabriel Lodewijks
Keyword(s):  
Traffic Flow ◽  
Flow Rate ◽  
Flow Simulation ◽  
Wave Theory ◽  
Flow Density ◽  
List Type ◽  
Ship Traffic ◽  
Traffic Wave ◽  
The Impact ◽  
Channel Segment

Abstract Abstract On the basis of the influence of dry season on ship traffic flow, the gathering and dissipating process of ship traffic flow was researched with Greenshields linear flow—density relationship model, the intrinsic relationship between the ship traffic congestion state and traffic wave in the unclosed restricted channel segment was emphatically explored when the ship traffic flow in a tributary channel inflows, and the influence law of multiple traffic waves on the ship traffic flow characteristics in unclosed restricted segment is revealed. On this basis, the expressions of traffic wave speed and direction, dissipation time of queued ships and the number of ships affected were provided, and combined with Monte Carlo method, the ship traffic flow simulation model in the restricted channel segment was built. The simulation results show that in closed restricted channel segment the dissipation time of ships queued is mainly related to the ship traffic flow rate of segments A and C, and the total number of ships affected to the ship traffic flow rate of segment A. And in unclosed restricted channel segment, the dissipation time and the total number of ships affected are also determined by the meeting time of the traffic waves in addition to the ship traffic flow rate of segments. The research results can provide the theoretical support for further studying the ship traffic flow in unclosed restricted channel segment with multiple tributaries Article Highlights The inflow of tributaries' ship traffic flows has an obvious impact on the traffic conditions in the unenclosed restricted channel segment. The interaction and influence between multiple ship traffic waves and the mechanism of generating new traffic waves are explained. The expression of both dissipation time of queued ships and the total number of ships affected in the closed and unclosed restricted channel segment are given.

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