Toward Affordable Uncertainty Quantification for Industrial Problems: Part II — Turbomachinery Application

2017 ◽  
Author(s):  
Tiziano Ghisu ◽  
Shahrokh Shahpar
Keyword(s):  
Uncertainty Quantification ◽  
Operating Conditions ◽  
High Fidelity ◽  
Jet Engine ◽  
Blade Shape ◽  
Shape Uncertainty ◽  
Polynomial Chaos Expansions ◽  
The Cost ◽  
The Impact ◽  
Bypass Ratio

Uncertainty Quantification (UQ) is an increasingly important area of research. As components and systems become more efficient and optimized, the impact of uncertain parameters (such as boundary and operating conditions, geometrical variations due to manufacturing or in-service deterioration, etc.) is likely to become critical. It is therefore fundamental to consider the impact of these uncertainties as early as possible during the design process, with the aim of producing more robust designs (less sensitive to the presence of uncertainties). The cost of UQ with high-fidelity simulations becomes therefore of fundamental importance. The companion part I paper presented an efficient approach for UQ based on Polynomial Chaos expansions, demonstrating its applicability to multi-fimensional uncertainty quantification problems. This paper focuses on the application of this approach to quantify the variability in the performance of two large bypass-ratio jet engine fans in the presence of shape uncertainty due to possible manufacturing processes. The impacts of shape uncertainty on the two geometries are compared, and sensitivities to the location of the blade shape variability are extracted. The mechanisms at the origin of the change in performance are analyzed in detail, as well as the differences between the two configurations. These results provide important information both for controling the manufacturing process, and for designing blades that are less sensitive to the presence of manufacturing uncertainties.

Affordable Uncertainty Quantification for Industrial Problems: Application to Aero-Engine Fans

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Tiziano Ghisu ◽  
Shahrokh Shahpar
Keyword(s):  
Uncertainty Quantification ◽  
Uncertainty Distribution ◽  
Blade Shape ◽  
Shape Uncertainty ◽  
Column Pivoting ◽  
The Cost ◽  
Sparse Grid Quadrature ◽  
The Impact ◽  
The Given ◽  
Bypass Ratio

Uncertainty quantification (UQ) is an increasingly important area of research. As components and systems become more efficient and optimized, the impact of uncertain parameters is likely to become critical. It is fundamental to consider the impact of these uncertainties as early as possible during the design process, with the aim of producing more robust designs (less sensitive to the presence of uncertainties). The cost of UQ with high-fidelity simulations becomes therefore of fundamental importance. This work makes use of least-squares approximations in the context of appropriately selected polynomial chaos (PC) bases. An efficient technique based on QR column pivoting has been employed to reduce the number of evaluations required to construct the approximation, demonstrating the superiority of the method with respect to full-tensor quadrature (FTQ) and sparse-grid quadrature (SGQ). Orthonormal polynomials used for the PC expansion are calculated numerically based on the given uncertainty distribution, making the approach optimal for any type of input uncertainty. The approach is used to quantify the variability in the performance of two large bypass-ratio jet engine fans in the presence of shape uncertainty due to possible manufacturing processes. The impacts of shape uncertainty on the two geometries are compared, and sensitivities to the location of the blade shape variability are extracted. The mechanisms at the origin of the change in performance are analyzed in detail, as well as the differences between the two configurations.

Direct Outer Ring Cooling of a High Speed Jet Engine Mainshaft Ball Bearing: Experimental Investigation Results

2010 ◽  
Author(s):  
Peter Gloeckner ◽  
Klaus Dullenkopf ◽  
Michael Flouros
Keyword(s):  
Power Dissipation ◽  
High Speed ◽  
Ball Bearing ◽  
Operating Conditions ◽  
Outer Ring ◽  
Outer Diameter ◽  
Propulsion Systems ◽  
Jet Engine ◽  
Power Loss Reduction ◽  
The Impact

Operating conditions in high speed mainshaft ball bearings applied in new aircraft propulsion systems require enhanced bearing designs and materials. Rotational speeds, loads, demands on higher thrust capability, and reliability have increased continuously over the last years. A consequence of these increasing operating conditions are increased bearing temperatures. A state of the art jet engine high speed ball bearing has been modified with an oil channel in the outer diameter of the bearing. This oil channel provides direct cooling of the outer ring. Rig testing under typical flight conditions has been performed to investigate the cooling efficiency of the outer ring oil channel. In this paper the experimental results including bearing temperature distribution, power dissipation, bearing oil pumping and the impact on oil mass and parasitic power loss reduction are presented.

Environmental liability and asset retirement obligations

2011 ◽  
Vol 51 (2) ◽  
pp. 697
Author(s):  
Michael Clark ◽  
John Claypool
Keyword(s):  
Oil And Gas ◽  
Operating Conditions ◽  
Federal State ◽  
Operating Life ◽  
Oil Companies ◽  
Oil And Gas Producers ◽  
State And Local ◽  
Well Abandonment ◽  
The Cost ◽  
The Impact

Oil companies, partnerships and entities developed for the exploration and/or production of hydrocarbons typically invest for a reasonably certain period of time, with the assets projected to have little or no value at the end of their life cycle. Historically, production facilities were decommissioned as cost effectively as possible, with limited consideration of the cost of this practice being factored into the initial costs or operating budgets, and the salvage value of the scrap metal was applied to cover the cost of the demolition. Today, most oil and gas producers are required to account for the estimated future cost of dismantling and removing facilities and equipment, as well as restoring land to its previous condition. The estimated costs for future dismantling, removal, and restoration are different to other costs associated with the acquisition and use of productive assets. The impact of potential environmental expenses associated with these practices typically occurs after an asset has ceased production. Planning for environmental costs for asset retirement obligations (AROs) is ideally conducted during the asset's operating life. This is so that compliance costs and other operating expenses are recorded consistently in conformance with accounting policies and regulations. Tentatively identified AROs include: asbestos, batteries, PCB transformers, underground or above ground storage tanks, well abandonment, waste impoundments, mercury, and other components of an active producing facility. Operators need to identify specific performance requirements that may impose obligations on their organisation. Federal, state and local requirements need be considered, as they apply to specific operating conditions.

scholarly journals Economics of an Additive Manufactured Heat Exchanger for Concentrating Solar Power

2022 ◽  
Author(s):  
Tracey Ziev ◽  
Erfan Rasouli ◽  
Ines Noelly-Tano ◽  
Ziheng Wu ◽  
Srujana Yarasi Rao ◽  
...  
Keyword(s):  
High Efficiency ◽  
Solar Power ◽  
Cost Model ◽  
Low Cost ◽  
Operating Conditions ◽  
Concentrated Solar Power ◽  
Future Technologies ◽  
The Cost ◽  
Alternative Current ◽  
The Impact

Developing low cost, high efficiency heat exchangers (HX) for application in concentrated solar power (CSP) is critical to reducing CSP costs. However, the extreme operating conditions in CSP systems present a challenge for typical high efficiency HX manufacturing processes. We describe a process-based cost model (PBCM) to estimate the cost of fabricating an HX for this application using additive manufacturing (AM). The PBCM is designed to assess the effectiveness of different designs, processes choices, and manufacturing innovations to reduce HX cost. We describe HX design and AM process modifications that reduce HX cost from a baseline of$780/kW-thto$570/kW-th. We further evaluate the impact of alternative current and potential future technologies on HX cost, and identify a pathway to further reduce HX cost to$270/kW-th.

A Fully Non-Adiabatic Flamelet Generated Manifold Model for High Fidelity Modeling of Turbulent Combustion in Gas Turbine Like Conditions

2020 ◽  
Author(s):  
Rakesh Yadav ◽  
Ishan Verma ◽  
Abhijit Modak ◽  
Shaoping Li
Keyword(s):  
Experimental Data ◽  
Gas Turbine ◽  
Turbulent Combustion ◽  
Gas Turbines ◽  
Turbulent Flame ◽  
Operating Conditions ◽  
High Fidelity ◽  
Mixture Density ◽  
Flamelet Generated Manifold ◽  
The Impact

Abstract Flamelet Generated Manifold (FGM) has proven to be an efficient approach to model turbulent combustion across different regimes of combustion. The manifolds are generally created by solving laminar premixed or opposed flow configurations. Gas turbine combustors often involve many strong non-adiabatic events such as multiple temperature boundaries, quenching from cooling and effusion holes, conjugate heat transfer, soot radiation interaction, phase change from spray and the modulation of inlet conditions. The adiabatic assumption of the underlying flamelet generation in the FGM is, therefore, prone to errors in the prediction of flame speed, liner temperatures, and pollutant formation. In this work, a novel approach to generate fully non-adiabatic manifold is proposed and validated. The FGM manifold is created using a series of non-adiabatic flamelets, each flamelet is solved in one-dimensional physical space. The non-adiabatic flamelets are generated with an optimal combination of freely propagating and burner stabilized flames. This hybrid method of the flamelet configuration allows modeling large heat gain and loss without encountering any unrealistic temperature in the flamelet solution. Such fully non-adiabatic flamelets are then convoluted to generate a five-dimensional Non-adiabatic Flamelet Generated Manifold (NFGM) Probability Density Function (PDF.). The average properties such as temperature, mixture density, species concentration, rate of reaction, etc. from PDF are then coupled with the CFD solution. The non-adiabatic flamelets and corresponding NFGM is implemented into ANSYS Fluent software version 2020R1. This approach is validated first for canonical cases, followed by gas turbine like conditions of swirl stabilized methane fueled turbulent flame, developed at DLR Stuttgart as the PRECCINSTA combustor. The experimental data for this combustor is available for multiple operating conditions. A stable operating point (φ = 0.83, P = 30 kW) is chosen. The proposed nonadiabatic NFGM is used with Stress blended eddy simulation (SBES). The current NFGM-SBES results are compared with experimental data as well as the previously published works. The impact of modeling heat release in flamelet is used to analyze the M-shape versus V-shape flame transition and the peaks of the carbon monoxide in mixing shear layers. The findings from the current work, in terms of accuracy, validity and best practices while modeling NFGM-SBES are discussed and summarized. The improved results of NFGM compared to adiabatic FGM are encouraging and provides a potential high-fidelity tool for accurate, yet efficient modeling of turbulent combustion inside gas turbines.

scholarly journals Coherent spin qubit transport in silicon

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
J. Yoneda ◽  
W. Huang ◽  
M. Feng ◽  
C. H. Yang ◽  
K. W. Chan ◽  
...  
Keyword(s):  
Fault Tolerant ◽  
High Fidelity ◽  
Nearest Neighbours ◽  
Quantum Processor ◽  
Spin Qubit ◽  
State Tomography ◽  
On Chip ◽  
The Cost ◽  
Silicon Based ◽  
The Impact

AbstractA fault-tolerant quantum processor may be configured using stationary qubits interacting only with their nearest neighbours, but at the cost of significant overheads in physical qubits per logical qubit. Such overheads could be reduced by coherently transporting qubits across the chip, allowing connectivity beyond immediate neighbours. Here we demonstrate high-fidelity coherent transport of an electron spin qubit between quantum dots in isotopically-enriched silicon. We observe qubit precession in the inter-site tunnelling regime and assess the impact of qubit transport using Ramsey interferometry and quantum state tomography techniques. We report a polarization transfer fidelity of 99.97% and an average coherent transfer fidelity of 99.4%. Our results provide key elements for high-fidelity, on-chip quantum information distribution, as long envisaged, reinforcing the scaling prospects of silicon-based spin qubits.

scholarly journals Uncertainty quantification in the design of wireless power transfer systems

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 391-396
Author(s):  
Yao Pei ◽  
Lionel Pichon ◽  
Mohamed Bensetti ◽  
Yann Le-Bihan
Keyword(s):  
Uncertainty Quantification ◽  
Wireless Power Transfer ◽  
Power Transfer ◽  
Wireless Power ◽  
Inductive Power Transfer ◽  
Variable Parameters ◽  
Material Parameters ◽  
Fast Prediction ◽  
Polynomial Chaos Expansions ◽  
The Impact

AbstractThe paper addresses the uncertainty quantification of physical and geometrical material parameters in the design of wireless power transfer systems. For 3D complex systems, a standard Monte Carlo cannot be directly used to extract statistical quantities. So, surrogate models based on Kriging or polynomial chaos expansions are built to study the impact of variable parameters on the radiated magnetic field and efficiency. Such fast prediction of uncertainties in the parameters of the system can improve the design of inductive power transfer systems taking into account human exposure recommendations and variability of the parameters.

Direct Outer Ring Cooling of a High Speed Jet Engine Mainshaft Ball Bearing: Experimental Investigation Results

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
Peter Gloeckner ◽  
Klaus Dullenkopf ◽  
Michael Flouros
Keyword(s):  
Power Dissipation ◽  
High Speed ◽  
Ball Bearing ◽  
Operating Conditions ◽  
Outer Ring ◽  
Outer Diameter ◽  
Propulsion Systems ◽  
Jet Engine ◽  
Power Loss Reduction ◽  
The Impact

Operating conditions in high speed mainshaft ball bearings applied in new aircraft propulsion systems require enhanced bearing designs and materials. Rotational speeds, loads, demands on higher thrust capability, and reliability have increased continuously over the last years. A consequence of these increasing operating conditions are increased bearing temperatures. A state of the art jet engine high speed ball bearing has been modified with an oil channel in the outer diameter of the bearing. This oil channel provides direct cooling of the outer ring. Rig testing under typical flight conditions has been performed to investigate the cooling efficiency of the outer ring oil channel. In this paper, the experimental results including bearing temperature distribution, power dissipation, and bearing oil pumping and the impact on oil mass and parasitic power loss reduction are presented.

scholarly journals Robust Aerodynamic Design of Nacelles for Future Civil Aero-Engines

2020 ◽  
Author(s):  
B. Deneys J. Schreiner ◽  
Fernando Tejero ◽  
David G. MacManus ◽  
Christopher Sheaf
Keyword(s):  
Design Method ◽  
Operating Conditions ◽  
Propulsive Efficiency ◽  
Multi Objective ◽  
Fuel Burn ◽  
Trade Offs ◽  
Specific Thrust ◽  
Aero Engines ◽  
The Impact ◽  
Bypass Ratio

Abstract As the growth of aviation continues it is necessary to minimise the impact on the environment, through reducing NOx emissions, fuel-burn and noise. In order to achieve these goals, the next generation of Ultra-High Bypass Ratio engines are expected to increase propulsive efficiency through operating at reduced specific thrust. Consequently, there is an expected increase in fan diameter and the associated potential penalties of nacelle drag and weight. In order to ensure that these penalties do not negate the benefits obtained from the new engine cycles, it is envisaged that future civil aero-engines will be mounted in compact nacelles. While nacelle design has traditionally been tackled by multi-objective optimisation at different flight conditions within the cruise segment, it is anticipated that compact configurations will present larger sensitivity to off-design conditions. Therefore, a design method that considers the different operating conditions that are met within the full flight envelope is required for the new nacelle design challenge. The method is employed to carry out multi-point multi-objective optimisation of axisymmetric aero-lines at different transonic and subsonic operating conditions. It considers mid-cruise conditions, end-of-cruise conditions, the sensitivity to changes in flight Mach number, windmilling conditions with a cruise engine-out case and an engine-out diversion scenario. Optimisation routines were conducted for a conventional nacelle and a future aero-engine architecture, upon which the aerodynamic trade-offs between the different flight conditions are discussed. Subsequently, the tool has been employed to identify the viable nacelle design space for future compact civil aero-engines for a range of nacelle lengths.

scholarly journals Optimal Design and Acoustic Assessment of Low-Vibration Rotor Blades

2016 ◽  
Vol 2016 ◽  
pp. 1-17 ◽  
Author(s):  
G. Bernardini ◽  
E. Piccione ◽  
A. Anobile ◽  
J. Serafini ◽  
M. Gennaretti
Keyword(s):  
Operating Conditions ◽  
Rotor Blades ◽  
Design Parameters ◽  
Blade Design ◽  
Genetic Optimization ◽  
Flow Conditions ◽  
Nonlinear Beam ◽  
Blade Shape ◽  
The Impact ◽  
Genetic Optimization Algorithm

An optimal procedure for the design of rotor blade that generates low vibratory hub loads in nonaxial flow conditions is presented and applied to a helicopter rotor in forward flight, a condition where vibrations and noise become severe. Blade shape and structural properties are the design parameters to be identified within a binary genetic optimization algorithm under aeroelastic stability constraint. The process exploits an aeroelastic solver that is based on a nonlinear, beam-like model, suited for the analysis of arbitrary curved-elastic-axis blades, with the introduction of a surrogate wake inflow model for the analysis of sectional aerodynamic loads. Numerical results are presented to demonstrate the capability of the proposed approach to identify low vibratory hub loads rotor blades as well as to assess the robustness of solution at off-design operating conditions. Further, the aeroacoustic assessment of the rotor configurations determined is carried out in order to examine the impact of low-vibration blade design on the emitted noise field.

Sign in / Sign up

Export Citation Format

Share Document