The Design and Performance of High-Pressure Injectors as Gas Jet Boosters

1970 ◽  
Vol 185 (1) ◽  
pp. 755-766 ◽  
Author(s):  
M. L. Hoggarth
Keyword(s):  
High Pressure ◽  
Distribution System ◽  
Theoretical Study ◽  
Distribution Networks ◽  
Operating Conditions ◽  
Optimum Operating ◽  
One Dimensional ◽  
And Performance ◽  
Optimum Working ◽  
Working Point

Injectors have a large potential application as jet boosters in gas distribution networks by using the gas from high-pressure supplies to boost the pressure of gas from low-pressure holders to that required by the distribution system. A theoretical study of the design and performance of injectors for this purpose is described. A one-dimensional theory which takes friction into account is proposed for predicting the performance of injectors with driving pressure ratios up to 14:1. Optimization of the theoretical equations is carried out so that the most suitable dimensions can be chosen for any specified performance. Alternatively, the best operating conditions for a given geometry may be predicted. Experimental results compared well with predictions from the proposed theory particularly in the region close to the optimum working point. Where deviations did occur these are explained by the excessive recirculation of the driving gas at the inlet to the mixing throat, when operated away from the optimum working point at low injection ratios and high pressure lifts. By moving the driving nozzle closer to the inlet of the throat and dispensing with the inlet cone, marked improvements in performance could be obtained at these off-optimum operating conditions.

scholarly journals Data-driven Adaptive Thresholding Model for Real-time Valve Delay Estimation in Digital Pump/Motors

2020 ◽  
Author(s):  
Abdallah Chehade ◽  
Farid Breidi ◽  
Keith Scott Pate ◽  
John Lumkes
Keyword(s):  
High Pressure ◽  
Real Time ◽  
Domain Knowledge ◽  
Operating Conditions ◽  
Delay Model ◽  
Hydraulic Systems ◽  
Pressure Transducers ◽  
Statistical Behavior ◽  
Shift Detection ◽  
And Performance

Valve characteristics are an essential part of digital hydraulics. The on/off solenoid valves utilized on many of these systems can significantly affect the performance. Various factors can affect the speed of the valves causing them to experience various delays, which impact the overall performance of hydraulic systems. This work presents the development of an adaptive statistical based thresholding real-time valve delay model for digital Pump/Motors. The proposed method actively measures the valve delays in real-time and adapts the threshold of the system with the goal of improving the overall efficiency and performance of the system. This work builds on previous work by evaluating an alternative method used to detect valve delays in real-time. The method used here is a shift detection method for the pressure signals that utilizes domain knowledge and the system’s historical statistical behavior. This allows the model to be used over a large range of operating conditions, since the model can learn patterns and adapt to various operating conditions using domain knowledge and statistical behavior. A hydraulic circuit was built to measure the delay time experienced from the time the signal is sent to the valve to the time that the valve opens. Experiments were conducted on a three piston in-line digital pump/motor with 2 valves per cylinder, at low and high pressure ports, for a total of six valves. Two high frequency pressure transducers were used in this circuit to measure and analyze the differential pressure on the low and high pressure side of the on/off valves, as well as three in-cylinder pressure transducers. Data over 60 cycles was acquired to analyze the model against real time valve delays. The results show that the algorithm was successful in adapting the threshold for real time valve delays and accurately measuring the valve delays. 

Two-Dimensional Performance Analysis and Design of MHD Channels

1981 ◽  
Vol 103 (2) ◽  
pp. 307-314 ◽  
Author(s):  
E. Doss ◽  
H. Geyer ◽  
R. K. Ahluwalia ◽  
K. Im
Keyword(s):  
Operating Conditions ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Channel Geometry ◽  
One Dimensional ◽  
Analysis And Design ◽  
Voltage Drops ◽  
And Performance ◽  
Carry Over ◽  
Mhd Channel

A two-dimensional model for MHD channel design and analysis has been developed for three different modes of operation: velocity, Mach number, and pressure. Given the distribution of any of these three parameters along the channel, the channel aspect ratio, and the channel operating conditions, the MHD channel geometry can be predicted. The developed two-dimensional design model avoids unnecessary assumptions for surface losses and boundary layer voltage drops that are required in one-dimensional calculations and, thus, can yield a better prediction of MHD channel geometry and performance. The subject model includes a simplified treatment for possible arcing near the electrode walls. A one-dimensional model for slag flow along the channel walls is also incorporated. The effects of wall temperature and slag carry-over on channel performance are discussed.

Experimental and Numerical Analysis of the Secondary Flow Across the Interphase Balance Drum of a High Pressure Back-to-Back Centrifugal Compressor

2017 ◽  
Author(s):  
Carmine Carmicino ◽  
Francesco Maiuolo ◽  
Emanuele Rizzo
Keyword(s):  
Experimental Data ◽  
High Pressure ◽  
Numerical Analysis ◽  
Pressure Distribution ◽  
Centrifugal Compressor ◽  
Operating Conditions ◽  
Local Pressure ◽  
Flow Angle ◽  
One Dimensional ◽  
Honeycomb Seal

With the major aim of gathering information on the machine lateral stability in high pressure-high density conditions, and of assessing the prediction capabilities of the in-house design tools and overall process, a back-to-back centrifugal compressor has been instrumented and tested in several operating conditions. The present paper focuses on the secondary flows across the interphase balance drum of the back-to-back compressor, where the sealing is accomplished with a honeycomb seal. The compressor interphase section has been instrumented with dedicated special probes for the clearance measurement associated to pressure and flow angle probes in order to characterize pressure distributions and swirl variations depending on the specific operating range. The experimental data acquired over the machine operation have been compared with a three-dimensional steady-state numerical analysis results obtained from the simulation, carried out with a Reynolds averaged Navier-Stokes (RANS) approach, of the flowfield in the complex interphase secondary system composed by the impeller cavities and the honeycomb seal. This paper addresses the comparison between numerical results and experimental data, which allowed the matching of models with experiments in terms of pressure distribution and the complex flowfield. Finally, all the data have been used to validate an in-house one-dimensional flow network solver for pressure distribution and leakage flow calculations along cavities and seals. Results have shown a general good agreement between measured data and calculation output. In particular, computational fluid dynamic analysis provided detailed pressure and velocity distributions that allowed gaining insight in the physics of such a complex region. The one-dimensional model has been demonstrated to be a fast and reliable tool to well predict local pressure variations inside cavities and seals and, consequently, the residual axial thrust.

scholarly journals High pressure experimental and theoretical study of the quasi-one-dimensional sulfides AV6S8(A = In, Tl)

2008 ◽  
Vol 121 (3) ◽  
pp. 032013 ◽  
Author(s):  
H D Hochheimer ◽  
C F Miclea ◽  
P Modak ◽  
A K Verma ◽  
R S Rao ◽  
...  
Keyword(s):  
High Pressure ◽  
Theoretical Study ◽  
One Dimensional

Exergy Analysis for the Performance of Solar Collectors

1983 ◽  
Vol 105 (2) ◽  
pp. 163-167 ◽  
Author(s):  
M. Fujiwara
Keyword(s):  
Performance Evaluation ◽  
Pressure Drop ◽  
Exergy Analysis ◽  
Operating Conditions ◽  
Exergy Loss ◽  
Optimum Operating ◽  
Solar Collectors ◽  
Optimum Control ◽  
Friction Process ◽  
And Performance

The optimum control and performance evaluation of solar collectors are analyzed from the standpoint of exergy. The pressure drop inside the collector is introduced to the analysis using the Hottel-Whillier model. By treating the friction process as exergy loss, the optimum operating conditions are presented in a simple statement. The maximum capability of collectors is determined and expressed by a relationship among the collector parameters and the environment in which they operates.

Experimental and numerical investigations of aerodynamic behavior of a three-stage high-pressure turbine at different operation conditions

2011 ◽  
Vol 226 (6) ◽  
pp. 1535-1549
Author(s):  
S Abdelfattah ◽  
M T Schobeiri
Keyword(s):  
High Pressure ◽  
Three Dimensional ◽  
Critical Discussion ◽  
Numerical Results ◽  
Operating Conditions ◽  
Steam Turbines ◽  
High Pressure Turbine ◽  
Numerical Investigations ◽  
Operation Conditions ◽  
And Performance

Using the Reynolds-averaged Navier–Stokes-based numerical methods to simulate the flow field, efficiency and performance of high-pressure turbine components of multi-stage steam turbines result in substantial differences between the experimental and the numerical results pertaining to the individual flow quantities. These differences are integrally noticeable in terms of major discrepancies in aerodynamic losses, efficiency, and performance of the turbine. As a consequence, engine manufacturers are compelled to frequently calibrate their simulation package by performing a series of experiments before issuing efficiency and performance guaranty. The aim of this article is to investigate the cause of the aforementioned differences by utilizing a three-stage high-pressure research turbine with three-dimensional compound lean blades as the platform for experimental and numerical investigations. Experimental data were obtained using interstage aerodynamic measurements at three measurement stations, namely, downstream of the first rotor row, the second stator row, and the second rotor row. Detailed measurements were conducted using custom-designed five-hole probes traversed in both circumferential and radial directions. Aerodynamic measurements were carried out within a rotational speed range of 1800–2800 r/min. Numerical simulations were performed utilizing a commercially available computational fluid dynamics code. A detailed mesh of the three stages was created and used to simulate the corresponding operating conditions. The experimental and numerical results were compared following a critical discussion relative to differences mentioned above.

scholarly journals Assessment of bacterial diversity in western Accra, Ghana, drinking water samples

2019 ◽  
Vol 9 (4) ◽  
pp. 644-661
Author(s):  
Gertrude Ecklu-Mensah ◽  
Sammy T. Sackey ◽  
Hilary G. Morrison ◽  
Mitchell L. Sogin ◽  
Leslie G. Murphy ◽  
...  
Keyword(s):  
Drinking Water ◽  
Bacterial Community ◽  
Bacterial Diversity ◽  
Distribution System ◽  
Water Distribution ◽  
Bacterial Community Composition ◽  
Distribution Networks ◽  
Minimum Entropy ◽  
Storage Unit ◽  
And Performance

Abstract The design and performance characteristics of municipal drinking water systems can profoundly influence public health. To assess the operational attributes of an Accra, Ghana drinking water distribution system, high-throughput 454 pyrosequencing was employed to characterize its bacterial community composition. Samples from the waterworks and four household sources (one household tap and three polytank storage units) were analyzed within one of the Accra's distribution networks over a 4-month period. Samples provided between 9,059 and 20,076 reads (average = 13,056) that represented a broad range of bacterial diversity, including rare genera. Minimum Entropy Decomposition (MED) analysis showed that the sequences described four major assemblages. Assemblages 1 and 2 dominated the waterworks and household tap samples while polytank storage unit samples, with one exception, contained assemblages 3 or 4. The considerable bacterial taxonomic difference between different sources suggests that contamination and/or selective growth shapes bacterial community structures after treatment at the waterworks. Of particular interest are the major differences between the polytank samples following storage and the tap/waterworks samples, suggesting that water storage (stagnation) can select for unique microbial populations.

scholarly journals Protection Coordination of Properly Sized and Placed Distributed Generations–Methods, Applications and Future Scope

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2672 ◽  
Author(s):  
Sunny Katyara ◽  
Lukasz Staszewski ◽  
Zbigniew Leonowicz
Keyword(s):  
Distribution System ◽  
Power Flow ◽  
Distribution Networks ◽  
Operating Conditions ◽  
System Stability ◽  
Distributed Generations ◽  
High Penetration ◽  
Multi Agent ◽  
Utility Network ◽  
Abnormal Operating Conditions

The radial distribution networks are designed for unidirectional power flows and are passive in nature. However, with the penetration of Distributed Generation (DG), the power flow becomes bidirectional and the network becomes active. The integration of DGs into distribution network creates many issues with: system stability, protection coordination, power quality, islanding, proper placement and sizing etc. Among these issues, the two most significant are optimal sizing and placement of DGs and their protection coordination in utility network. The proper coordination of relays with high penetration of DGs placed at optimal location increases the availability and reliability of the network during abnormal operating conditions. This research addresses most of the available methods for efficient sizing and placement of DGs in distribution system (numerical, analytical and heuristic) as well as the developed protection coordination techniques for utility networks in the presence of DGs (Artificial Intelligence (AI), adaptive and non-adaptive, multi-agent, hybrid). This paper indicates the possible research gaps and highlights the applications possibilities and methods’ limitations in the area of DGs.

scholarly journals Removal of 4-Nitrophenol from Aqueous Solution by Using Polyphenylsulfone-Based Blend Membranes: Characterization and Performance

Membranes ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 171
Author(s):  
Ali Amer Yahya ◽  
Khalid T. Rashid ◽  
Maryam Y. Ghadhban ◽  
Noor Edin Mousa ◽  
Hasan Shaker Majdi ◽  
...  
Keyword(s):  
Pore Size ◽  
Cross Section ◽  
Feed Solution ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Operational Variables ◽  
Blend Membranes ◽  
Dope Solution ◽  
And Performance ◽  
The Impact

Among many contaminants in wastewater, organic phenol compounds presented a major concern to endanger the water resources safety. In the present study, blend nanofiltration (NF) membranes comprising polyphenylsulfone (PPSU) and polyethersulfone (PES) were prepared via the non-induced phase separation and their performance was examined against 4-Nitrophenol (4-NP). The PES ratio in the dope solution was varied from 6 to 9 wt.% to probe the impact of PES on the retention and permeation characteristics of the final membranes. A series of experimental tools were employed to estimate the characteristics of the membranes, including surface and cross-section, hydrophilicity, pore size and pore size distribution. Performance evaluation of the NF membranes was conducted considering two operational variables; pH and initial feed solution. About 99% removal of 4-NP along with 6.2 L/m2.h.bar was achieved at the optimum operating conditions as revealed by optimization and mathematical modelling.

scholarly journals A Chance-Constrained Multistage Planning Method for Active Distribution Networks

Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4154
Author(s):  
Nikolaos Koutsoukis ◽  
Pavlos Georgilakis
Keyword(s):  
Distribution System ◽  
Net Present Value ◽  
Distribution Networks ◽  
Planning Method ◽  
Chance Constrained Programming ◽  
Expansion Plan ◽  
Total Investment ◽  
And Performance ◽  
Constrained Programming ◽  
Active Distribution Networks

This paper introduces a multistage planning method for active distribution networks (ADNs) considering multiple alternatives. The uncertainties of load, wind and solar generation are taken into account and a chance constrained programming (CCP) model is developed to handle these uncertainties in the planning procedure. A method based on a k-means clustering technique is employed for the modelling of renewable generation and load demand. The proposed solution methodology, which is based on a genetic algorithm, considers multiple planning alternatives, such as the reinforcement of substations and distribution lines, the addition of new lines, and the placement of capacitors and it aims at minimizing the net present value of the total operation cost plus the total investment cost of the reinforcement and expansion plan. The active network management is incorporated into planning method in order to exploit the control capabilities of the output power of the distributed generation units. To validate its effectiveness and performance, the proposed method is applied to a 24-bus distribution system.

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