scholarly journals Radial turbine sound and noise characterisation with acoustic transfer matrices by means of fast one-dimensional models

2019 ◽  
pp. 146808741988942
Author(s):  
Antonio Torregrosa ◽  
Luis Miguel García-Cuevas ◽  
Lukas Benjamin Inhestern ◽  
Pablo Soler
Keyword(s):  
Mean Value ◽  
Operating Conditions ◽  
Design Stage ◽  
Transfer Matrices ◽  
Efficient Manner ◽  
One Dimensional ◽  
Engine Design ◽  
Lookup Tables ◽  
Single Entry ◽  
Radial Turbines

Estimating correctly the turbine acoustics can be valuable during the engine design stage; in fact, it can lead to a more optimised design of the silencer and aftertreatment, as well as to better prediction of the scavenging effects. However, obtaining the sound and noise emissions of radial turbocharger turbines with low computational costs can be challenging. To consider these effects in a time-efficient manner, the acoustic response of single-entry radial turbines can be characterised by means of acoustic transfer matrices that change with the operating conditions. Exploiting the different time-scales of the acoustic phenomena and the change in the operating point of the turbine, lookup tables of acoustic transfer matrices can be computed. Then, the obtained characterisation can be used in mean-value engine models. This article presents a method for generating these lookup tables by means of fast one-dimensional simulations of thoroughly validated fidelity, in terms of both acoustics and extrapolation capabilities. Due to the inherent behaviour of radial turbines, the number of computations needed to fill the lookup tables is relatively small, so the method can be used as a simple preprocessing phase before mean-value simulation campaigns.

Investigation on the Degree of Reaction in Twin Scroll Radial Turbines at Different Operating Conditions for Turbocharging Applications

2019 ◽  
Author(s):  
Carlo Cravero ◽  
Davide De Domenico ◽  
Andrea Ottonello
Keyword(s):  
High Performance ◽  
Mean Value ◽  
Operating Conditions ◽  
Axial Thrust ◽  
Degree Of Reaction ◽  
Radial Turbine ◽  
Wide Range ◽  
Partial Admission ◽  
Rotor Losses ◽  
Radial Turbines

Abstract Frequently in turbocharging radial turbine studies, some assumptions have to be done in order to make 1D matching calculations as easy as possible and to develop simulation approaches that can be useful for different purposes, like axial thrust prediction. One of these assumptions concerns the degree of reaction, which is often considered constant and equal to the value 0.5. In standard radial turbines design the velocity triangles are set by the target to keep a mean degree of reaction of 50%, in order to obtain low rotor losses and to minimize the exit swirl to get lower losses in the exhaust diffuser. From the experience gained on radial turbines operating in a wide range of conditions, it is evident that: the degree of reaction presents large variations along a given isospeed (especially at low rotational speed) and the mean value is far from 0.5 (particularly true in high performance applications). In the present work a method for the representation of the degree of reaction for radial turbine is suggested. The approach has been developed onto a twin scroll radial turbine for turbocharging, considering a large dataset of operating conditions (at both equal and partial admission). The discussion and the method suggested are based on a rich database from experimental data and numerical simulations developed by the authors on the 3D configuration of the turbines under investigation.

A Direct Performance Comparison of Vaned and Vaneless Stators for Radial Turbines

2006 ◽  
Vol 129 (1) ◽  
pp. 53-61 ◽  
Author(s):  
S. W. T. Spence ◽  
R. S. E. Rosborough ◽  
D. Artt ◽  
G. McCullough
Keyword(s):  
Performance Comparison ◽  
Performance Model ◽  
Operating Conditions ◽  
One Dimensional ◽  
Turbine Performance ◽  
Radial Turbine ◽  
Surface Finishes ◽  
The Impact ◽  
Radial Turbines ◽  
Extensive Performance

An extensive performance investigation has been conducted on a radial turbine with three different vaneless volutes and three corresponding vaned stators. Previously published comparisons have been based on turbines with unmatched flow rates, meaning that the impact of stator losses was not isolated from rotor and exit losses. Each vaned stator configuration tested in this investigation matched the flow rate of the corresponding vaneless volute to within 1%. The volutes and the vaned stators were all machined in order to achieve high quality and comparable surface finishes. At all operating conditions, the vaneless volutes were shown to deliver a significant efficiency advantage over the vaned stators. However, the vaneless volute turbines did not demonstrate any greater tolerance for off-design operating conditions than the vaned stator configurations. Full performance data are presented for the six different turbine configurations tested and a one-dimensional turbine performance model is evaluated as a means of predicting and extrapolating turbine performance.

Numerical Simulation of Stirling Engines Using an Unsteady Quasi-One-Dimensional Approach

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Niklas Andersson ◽  
Lars-Erik Eriksson ◽  
Martin Nilsson
Keyword(s):  
Oscillatory Flow ◽  
Computer Code ◽  
Operating Conditions ◽  
Wall Friction ◽  
Smoothing Algorithm ◽  
Dimensional Approach ◽  
One Dimensional ◽  
Flow Equations ◽  
Engine Design ◽  
Stirling Engines

An existing computer code for solving the quasi-one-dimensional (Q1D) flow equations governing unsteady compressible flow in tubes with smoothly varying cross section areas has been adapted to the simulation of the oscillatory flow in Stirling engines for engine design purposes. By utilizing an efficient smoothing algorithm for the area function that preserves the total volume of the tube, it has been possible to achieve a highly accurate and fully conservative numerical scheme. Submodels for wall friction and heat transfer have been added, enabling the simulation of gas heaters, gas coolers, and regenerators. The code has been used for the modeling of an α-type Stirling engine and validated for a range of operating conditions with good results.

scholarly journals Managing energy performance in buildings from design to operation using modelling and calibration

2021 ◽  
pp. 014362442110083
Author(s):  
Nishesh Jain ◽  
Esfand Burman ◽  
Dejan Mumovic ◽  
Mike Davies
Keyword(s):  
Best Practice ◽  
Good Practice ◽  
Energy Performance ◽  
Operating Conditions ◽  
Design Stage ◽  
Performance Gap ◽  
Actual Performance ◽  
Simulation Tools ◽  
Calibration Protocol ◽  
Covering Design

To manage the concerns regarding the energy performance gap in buildings, a structured and longitudinal performance assessment of buildings, covering design through to operation, is necessary. Modelling can form an integral part of this process by ensuring that a good practice design stage modelling is followed by an ongoing evaluation of operational stage performance using a robust calibration protocol. In this paper, we demonstrate, via a case study of an office building, how a good practice design stage model can be fine-tuned for operational stage using a new framework that helps validate the causes for deviations of actual performance from design intents. This paper maps the modelling based process of tracking building performance from design to operation, identifying the various types of performance gaps. Further, during the operational stage, the framework provides a systematic way to separate the effect of (i) operating conditions that are driven by the building’s actual function and occupancy as compared with the design assumptions, and (ii) the effect of potential technical issues that cause underperformance. As the identification of issues is based on energy modelling, the process requires use of advanced and well-documented simulation tools. The paper concludes with providing an outline of the software platform requirements needed to generate robust design models and their calibration for operational performance assessments. Practical application The paper’s findings are a useful guide for building industry professionals to manage the performance gap with appropriate accuracy through a robust methodology in an easy to use workflow. The methodological framework to analyse building energy performance in-use links best practice design stage modelling guidance with a robust operational stage investigation. It helps designers, contractors, building managers and other stakeholders with an understanding of procedures to follow to undertake an effective measurement and verification exercise.

Experimental assessment of the rotor outlet flow in a twin-entry radial turbine by means of Laser Doppler Anemometry

2021 ◽  
pp. 146808742110344
Author(s):  
José Galindo ◽  
Andrés Omar Tiseira ◽  
Luis Miguel García-Cuevas ◽  
Nicolás Medina
Keyword(s):  
Laser Doppler Anemometry ◽  
Effective Area ◽  
Laser Doppler ◽  
Flow Ratio ◽  
One Dimensional ◽  
Radial Turbine ◽  
Single Entry ◽  
Outlet Flow ◽  
Dimensional Models ◽  
Number Of Particles

The current paper presents the validation of some hypotheses used for developing a one-dimensional twin-entry turbine model with experimental measurements. A Laser Doppler Anemometry (LDA) technique has been used for measuring the axial Mach number and for counting the number of particles downstream of the rotor outlet. These measurements have been done for different mass flow ratio (MFR) and reduced turbocharger speed conditions. The flow coming from each turbine entry does not fully mix with the other within the rotor since, downstream of the rotor, they can still be differentiated. Thus, the hypothesis of studying twin-entry turbines as two separated single-entry turbines in one-dimensional models is corroborated. Moreover, the rotor outlet area corresponding to each flow branch has linear trends with the MFR value. Therefore, the rotor outlet effective area used for one-dimensional models should vary linearly with the MFR value.

CFD Investigation of Downhole Natural Gas Separation Efficiency in the Churn Flow Regime

2021 ◽  
Author(s):  
Charles Okafor ◽  
Patrick Verdin ◽  
Phill Hart
Keyword(s):  
Natural Gas ◽  
Flow Regime ◽  
Gas Separation ◽  
Separation Efficiency ◽  
Operating Conditions ◽  
Analytical Models ◽  
Design Stage ◽  
Average Error ◽  
Multiphase Model ◽  
Churn Flow

Abstract Downhole Natural Gas Separation Efficiency (NGSE) is flow regime dependent, and current analytical models in certain conditions lack accuracy. Downhole NGSE was investigated through 3D Computational Fluid Dynamics (CFD) transient simulations for pumping wells in the Churn flow regime. The Volume of Fluid (VOF) multiphase model was considered along with the k – ε turbulence model for most simulations. A mesh independence study was performed, and the final model results validated against experimental data, showing an average error of less than 6 %. Numerical simulation results showed that the steady state assumption used by current mathematical models for churn flow can be inaccurate. Several key parameters affecting the NGSE were identified, and suggestions for key improvements to the widely used mathematical formulations for viscous flow provided. Sensitivity studies were conducted on fluid/geometric parameters and operating conditions, to gain a better understanding of the influence of each parameter on NGSE. These are important results as they equip the ESP engineer with additional knowledge to maximise the NGSE from design stage to pumping operations.

Damping Behavior of Blades From Small Radial Turbines

2015 ◽  
Author(s):  
David Hemberger ◽  
Dietmar Filsinger ◽  
Hans-Jörg Bauer
Keyword(s):  
Numerical Analysis ◽  
Dynamic Properties ◽  
Forced Response ◽  
Operating Conditions ◽  
Fe Model ◽  
Structural Damping ◽  
Aerodynamic Damping ◽  
Damping Behavior ◽  
Aerodynamic Properties ◽  
Radial Turbines

Next to excitation forces and the dynamic properties of mistuned structures the damping behavior is a key feature to evaluate the dynamic turbine blade response and thus the HCF life of a bladed disk (blisk). Just as the determination of the mistuning properties and the assessment of the vibration excitation, the evaluation of damping is also subject to uncertainty especially considering the wide operating range of a small radial turbine of a turbocharger. Since the total damping is composed of material damping, structural damping and aerodynamic damping, which are affected by parameters, like the eigenform of the vibration, the magnitude of the vibration amplitude and aerodynamic properties, the total damping can be strongly dependent on the operating conditions. The study at hand provides results from investigations that allow estimating the contribution of aerodynamic damping on the total damping. Experimental and numerical analysis of radial turbines from turbochargers for vehicular engines with variable turbine inlet vanes were performed. Measurements under different environmental conditions such as at rest and during operation, as well as unsteady CFD calculations and, coupled flow and structural calculations were carried out. A change in total damping could be found depending on the density of the surrounding gas by vibration measurements in operation on the hot gas test bench. But it was also shown that the total damping is decisively influenced by the mistuning of the structure. On one side the structural damping is varied by the variation in mistuned blade vibration amplitudes and otherwise the aerodynamic damping is influenced by the different inter blade phase angles (IBPA ) due to the mistuning, which is a symptom of geometric differences and material inhomogeneity in the wheels. Finally, the estimated total damping values were utilized in forced response calculations using a mistuned FE-model of a real turbine and excitation forces from unsteady CFD calculation. The magnitudes of the measured vibration amplitudes were compared with results from numerical analysis to validate the numerical model with focus on the investigation about the total damping. The deviation between the results was ±10% for different eigenforms and excitation orders.

scholarly journals Material Origins of Accelerated Operational Wear of RD-33 Engine Blades

2020 ◽  
Author(s):  
Adam Kozakiewicz ◽  
Stanislaw Jóźwiak ◽  
Przemysław Jóźwiak ◽  
Stanisław Kachel
Keyword(s):  
Chemical Composition ◽  
Construction Material ◽  
Operating Conditions ◽  
Design Stage ◽  
Strength Analysis ◽  
Jet Engine ◽  
Emergency Situations ◽  
Low Pressure Turbine ◽  
Propulsion Unit ◽  
Selection Of

The structural and strength analysis of the material used to construct such an important engine element as the turbine is of great significance, both at the design stage as well as during tests and expertises related to emergency situations. Bearing in mind the conditions above mentioned, the paper presents the results of research on the chemical composition, morphology and phased structure of the metallic construction material used to produce the blades of the high and low pressure turbine of the RD-33 jet engine, which is the propulsion unit of the MiG-29 aircraft. The data obtained as a result of the material tests of the blades allowed, on the basis of the analysis of chemical composition and phased structure, to determine the grade of the alloy used to construct the tested elements of the jet engine turbine. The structural stability of the material was found to be lower in comparison with engine operating conditions, which manifested itself as a clear decrease in the resistance properties of the blade material. The results obtained can be used as a basis for analyzing the life span of an object or a selection of material replacements, which enable to produce the analyzed engine element.

scholarly journals Reliable simple zonal method of the furnace thermal calculation

2005 ◽  
Vol 9 (2) ◽  
pp. 45-55
Author(s):  
Vladan Ivanovic
Keyword(s):  
Energy Consumption ◽  
Flue Gas ◽  
Thermal Load ◽  
Operating Conditions ◽  
Thermal Calculation ◽  
Gas Temperature ◽  
Zonal Method ◽  
One Dimensional ◽  
Furnace Performance ◽  
Steam Boilers

The calculation of the furnace in the industrial and power boilers is the most important and the most responsible part of the thermal calculation, and it has important influence on the rationalization of energy consumption. In the paper one-dimensional zonal method of the furnace thermal calculation of steam boilers is presented. It can successfully define disposition of flue gas temperature and specific thermal load of screen walls with height of the furnace in case of uneven deposits distribution which vary in size and quality. Its greatest use is for comparing furnace performance under various operating conditions.

scholarly journals Hydrodynamic and hydrostatic forces as factors affecting tailing dump stability

2021 ◽  
Vol 44 (1) ◽  
pp. 63-72
Author(s):  
D. Sh. Sharipov
Keyword(s):  
Research Methods ◽  
Operating Conditions ◽  
Design Stage ◽  
Tailing Dump ◽  
Initial Development ◽  
Technical Problems ◽  
Factors Affecting ◽  
Deformation Processes ◽  
Tailing Dams ◽  
The Impact

The study of the processes occurring deep in the earth's crust has always been a relevant research topic. The results of these studies allowed development and safe mining of mineral deposits in various conditions. The growth in the consumption of extracted resource and the increase in the scale of mining are forcing enterprises to search for the solutions to complex engineering and technical problems, one of which is the problem of displacement of rock masses and the earth's surface in industrial production-affected areas including tailings dams. The purpose of this study is to improve the operation safety of tailing dams. The object of the study is embankment dams of dressing plant tailing dumps. The subject of the study is deformation processes occurring in dam bodies and slope surfaces. The main research methods used in the work are: the study of safe operation methods for tailing dams based on the operating conditions of Uchalinskoye tailing dump using the modern methods of stability assessment, analysis and generalization of domestic and foreign experience, as well as the study of current methods of geomechanical monitoring of deformation processes – engineering and geological, geophysical, mine surveying and hydrogeological ones. The article describes geographic, hydrographic, climatic, geological and mining operation conditions of the tailing dump of Uchalinsky GOK (Ore Mining and Processing Plant) JSC. The influence of hydrodynamic and hydrostatic forces on embankment tailing dam stability is substantiated. Based on the data obtained and the research methods used, it is concluded that hydrodynamic and hydrostatic forces are fundamental destructive factors affecting dams. The results of these studies can be applied at the design stage of hydraulic structures, since they will supplement theoretical knowledge about the impact of liquid waste on the safety of tailing dams and earth-filled dams, as well as allow detecting deformation processes at their initial development stage and making decisions on their elimination.

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