Alessandro Corsini - Academia.edu (original) (raw)
Papers by Alessandro Corsini
Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 2014
Volume 1: Aircraft Engine; Fans and Blowers; Marine, 2015
Volume 1A: Aircraft Engine; Fans and Blowers, 2014
Volume 6: Ceramics; Controls, Diagnostics and Instrumentation; Education; Manufacturing Materials and Metallurgy; Honors and Awards, 2015
ISRN Mechanical Engineering, 2013
This paper reviews modelling and interpretation advances of industrial fan stall phenomena, relat... more This paper reviews modelling and interpretation advances of industrial fan stall phenomena, related stall detection methods, and control technologies. Competing theories have helped engineers refine fan stability and control technology. With the development of these theories, three major issues have emerged. In this paper, we first consider the interplay between aerodynamic perturbations and instability inception. An understanding of the key physical phenomena that occurs with stall inception is critical to alleviate stall by design or through active or passive control methods. We then review the use of passive and active control strategies to improve fan stability. Whilst historically compressor design engineers have used passive control techniques, recent technologies have prompted them to install high-response stall detection and control systems that provide industrial fan designers with new insight into how they may detect and control stall. Finally, the paper reviews the methods and prospects for early stall detection to complement control systems with a warning capability. Engineers may use an effective real-time stall warning system to extend a fan's operating range by allowing it to operate safely at a reduced stall margin. This may also enable the fan to operate in service at a more efficient point on its characteristic.
ISRN Mechanical Engineering, 2013
Members of the aerospace fan community have systematically developed computational methods over t... more Members of the aerospace fan community have systematically developed computational methods over the last five decades. The complexity of the developed methods and the difficulty associated with their practical application ensured that, although commercial computational codes date back to the 1980s, they were not fully exploited by industrial fan designers until the beginning of the 2000s. The application of commercial codes proved to be problematic as, unlike aerospace fans, industrial fans include electrical motors and other components from which the flow will invariably separate. Consequently, industrial fan designers found the application of commercial codes challenging. The decade from 2000 to 2010 was focused on developing techniques that would facilitate converged solutions that predicted the fans' performance characteristics over the stable part of their operating range with reasonable accuracy, using a practical computational effort. In this paper, we focus on elucidating aspects of the flow physics that one cannot easily study in a laboratory environment, discussing the challenges involved and the relative merits of the available modelling techniques. The paper ends with a discussion of the practical problems associated with the use of commercial codes in a development environment and finally the legislation that is driving the need for aerospace style computation methods.
Journal of Fluids Engineering, 2013
Volume 3: Controls, Diagnostics and Instrumentation; Cycle Innovations; Marine, 2010
... [7] proposed a stall-warning index (utilising ... when the signal-to-noise ratio (or, more pr... more ... [7] proposed a stall-warning index (utilising ... when the signal-to-noise ratio (or, more precisely, the instability signature-to-background noise ratio) is lowas is the case with regard to rotorstall-inception at ... [15] note that the relative positions of probes and blades influence visual ...
Journal of Engineering for Gas Turbines and Power, 2012
Volume 1A: Aircraft Engine; Fans and Blowers, 2014
Regulations require that industrial fans utilised in power generation, cement and steel applicati... more Regulations require that industrial fans utilised in power generation, cement and steel applications must operate as part of a process that produces erosive particles. Over time these erosive particles erode centrifugal fan impeller blades, changing the blade profile and consequently, degrading fan performance. To replace the eroded impellers, operators must shut down the process. If one must replace an impeller between scheduled maintenance intervals, the associated costs with lost production become significant. Consequently, the industrial fan community is interested in predicting the erosion, and ultimately, a fan impeller's in-service life when operating in an erosive environment. Industrial fan designers face challenges when attempting to predict impeller erosion. Industrial centrifugal fan impeller blades are routinely constructed from cambered plate, usually with backward or forward sweeping, with the inevitable consequence of separated flow regions. This separated flow is within a highly three dimensional flow-field making difficult an accurate prediction of the flow-field though an impeller with cambered plate blades. Assuming that one can accurately predict this three dimensional flow-field one must then go on to simulate the erosive particles' trajectory.
Periodica Polytechnica Mechanical Engineering, 2014
Application of computational methods to industrial fan design processes has progressed steadily o... more Application of computational methods to industrial fan design processes has progressed steadily over the past decade. The reducing cost of the computer hardware upon which codes run has brought the hardware within the reach of all industrial fan designers. However, the cost of commercially available codes remains high. Open source codes provide industrial fan designers with an alternative. The finite volume open-source solver OpenFOAM has been used by scholars to predict the performance of industrial centrifugal fans incorporating impeller blades constructed from cambered plate, but not by industrial fan designers. This paper presents a modelling approach which we developed for application as part of an industrial fan manufacturers order related design process. We compare numerical performance predictions with experimental results both at peak pressure and at peak efficiency conditions. As a further possible investigation, the simulated flow field is used to predict the patterns of erosion of the impeller.
Volume 4: Ceramics; Concentrating Solar Power Plants; Controls, Diagnostics and Instrumentation; Education; Electric Power; Fans and Blowers, 2013
ABSTRACT We report on a numerical study on the performance of an innovative axial flow fan for la... more ABSTRACT We report on a numerical study on the performance of an innovative axial flow fan for large tunnel ventilation. Taking a lead from a previous biomimetic analysis on the performance of the flippers of the humpback whale, this whale-fan was designed with sinusoidal-like leading edge that mimic the tubercles of the whale. We found that this provided a resistance to stall and improved lift recovery in post-stall operations. The sinusoidal profile of the leading edge allowed to control the distribution of vorticity on the suction surface of the blades and increase the stall margin of the device.The paper discusses the design methodology that was followed to correlate the sinusoidal shape of the leading edge of the blade with the desired vorticity distribution at the trailing edge that was needed to control separation.In the paper we show the results of numerical computations carried out with the finite volume open-source code OpenFOAM on the whale-fan as well as a baseline fan with straight leading edge. Reynolds Averaged Navier-Stokes equations for incompressible flow were solved with a non-linear (cubic) eddy-viscosity k-ε model that was found able to control the eddy viscosity distribution in order to account for anisotropy of Reynolds stresses and better reproduce the three-dimensional properties of the flow field.The paper shows the performance chart of the whale-fan, derived from numerical computations, and gives an insight of the fluid flow mechanisms that are generated by the sinusoidal leading edge on the suction surface of the fan. A comparison with the baseline fan with straight leading edge is provided in order to highlight how the shape of the leading edges affect the performance of the fan.
Journal of Vibration and Acoustics, 2011
Advances in Acoustics and Vibration, 2013
There are controversial requirements involved in developing numerical methodologies in order to c... more There are controversial requirements involved in developing numerical methodologies in order to compute the flow in industrial fans. The full resolution of turbulence spectrum in such high-Reynolds number flow configurations entails unreasonably expensive computational costs. The authors applied the study to a large unidirectional axial flow fan unit for tunnel ventilation to operate in the forward direction under ambient conditions. This delivered cooling air to the tunnel under routine operation, or hot gases at 400 ∘ C under emergency conditions in the event of a tunnel fire. The simulations were carried out using the open source code OpenFOAM, within which they implemented a very large eddy simulation (VLES) based on one-equation SGS model to solve a transport equation for the modelled (subgrid) turbulent kinetic energy. This subgrid turbulence model improvement is a remedial strategy in VLES of high-Reynolds number industrial flows which are able to tackle the turbulence spectrum's well-known insufficient resolution. The VLES of the industrial fan permits detecting the unsteady topology of the rotor flow. This paper explores the evolution of secondary flow phenomena and speculates on its influence on the actual load capability when operating at peakpressure condition. Predicted noise emissions, in terms of sound pressure level spectra, are also compared with experimental results and found to agree within the uncertainty of the measurements.
The Journal of the Acoustical Society of America, 2010
ABSTRACT Because of the global civil regulation concerning acoustic emission, the goal of the man... more ABSTRACT Because of the global civil regulation concerning acoustic emission, the goal of the manufacturers is to substantially decrease the noise radiated by the low-speed fans, without degrading their aerodynamic performance. One of the main goal to accomplish this target is the evaluation of the unsteady aerodynamic sources in the fan rotor responsible for the noise emission. An experimental analysis, based on a cause-effect method, was carried out and the results are presented in this paper. The process focuses on the experimental comparison between the novel prototypes of a family of low-speed fans and enabled the evaluation of the noise sources in the rotor near-field domain. The near-field aerodynamic sources accounted in this work correspond to the zones with high pressure fluctuations amplitude, located in the wake region of the exhaust flow. The sources were measured along the rotor radius and then correlated with the noise emitted by the fan at the far-field domain, using a Fourier based methodology. The analysis was carried out looking at the cross-spectra polar form using the phase shift as revealing tool for aerodynamic noise sources. The results were compared to evaluate the merit of the aero-acoustic performance of each prototype.
Journal of Engineering for Gas Turbines and Power, 2011
... stress, related to the change from normal operation to rotating stall, with a relatively smal... more ... stress, related to the change from normal operation to rotating stall, with a relatively small change in measured unsteady pressure over the fan-blade tip. The small changes in measured unsteadypressure result in traditional fan and compressor stall-warning systems being ...
Periodica Polytechnica Mechanical Engineering, 2013
Journal of Fluids Engineering, 2013
ABSTRACT In this paper we discuss a computational method focused on the prediction of unsteady ae... more ABSTRACT In this paper we discuss a computational method focused on the prediction of unsteady aerodynamics, adequate for industrial turbomachinery. Here we focus on a single rotor device selected from a new family of large tunnel ventilation axial flow fans. The flow field in the fan was simulated using the open source code OPENFOAM, with a large-eddy simulation (LES) approach. The sub-grid scale (SGS) closure relied on a one-equation model, that requires us to solve a differential transport equation for the modeled SGS turbulent kinetic energy. The use of such closure was here considered as a remedial strategy in LES of high-Reynolds industrial flows, being able to tackle the otherwise insufficient resolution of turbulence spectrum. The results show that LES of the fan allows to predict the pressure rise capability of the fan and to reproduce the most relevant flow features, such as three-dimensional separation and secondary flows.
International Journal for Numerical Methods in Fluids, 2007
ABSTRACT The YZβ shock-capturing technique was introduced recently for use in combination with th... more ABSTRACT The YZβ shock-capturing technique was introduced recently for use in combination with the streamline-upwind/Petrov–Galerkin formulation of compressible flows in conservation variables. The YZβ shock-capturing parameter is much simpler than an earlier parameter derived from the entropy variables for use in conservation variables. In this paper, we propose to use the YZβ shock-capturing in combination with the variable subgrid scale (V-SGS) formulation of compressible flows in conservation variables. The V-SGS method is based on an approximation of the class of SGS models derived from the Hughes variational multiscale method. We evaluate the performance of the V-SGS and YZβ combination in a number of standard, 2D test problems. Compared to the earlier shock-capturing parameter derived from the entropy variables, in addition to being much simpler, the YZβ shock-capturing parameter yields better shock quality in these test problems. Copyright © 2007 John Wiley & Sons, Ltd.
Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 2014
Volume 1: Aircraft Engine; Fans and Blowers; Marine, 2015
Volume 1A: Aircraft Engine; Fans and Blowers, 2014
Volume 6: Ceramics; Controls, Diagnostics and Instrumentation; Education; Manufacturing Materials and Metallurgy; Honors and Awards, 2015
ISRN Mechanical Engineering, 2013
This paper reviews modelling and interpretation advances of industrial fan stall phenomena, relat... more This paper reviews modelling and interpretation advances of industrial fan stall phenomena, related stall detection methods, and control technologies. Competing theories have helped engineers refine fan stability and control technology. With the development of these theories, three major issues have emerged. In this paper, we first consider the interplay between aerodynamic perturbations and instability inception. An understanding of the key physical phenomena that occurs with stall inception is critical to alleviate stall by design or through active or passive control methods. We then review the use of passive and active control strategies to improve fan stability. Whilst historically compressor design engineers have used passive control techniques, recent technologies have prompted them to install high-response stall detection and control systems that provide industrial fan designers with new insight into how they may detect and control stall. Finally, the paper reviews the methods and prospects for early stall detection to complement control systems with a warning capability. Engineers may use an effective real-time stall warning system to extend a fan's operating range by allowing it to operate safely at a reduced stall margin. This may also enable the fan to operate in service at a more efficient point on its characteristic.
ISRN Mechanical Engineering, 2013
Members of the aerospace fan community have systematically developed computational methods over t... more Members of the aerospace fan community have systematically developed computational methods over the last five decades. The complexity of the developed methods and the difficulty associated with their practical application ensured that, although commercial computational codes date back to the 1980s, they were not fully exploited by industrial fan designers until the beginning of the 2000s. The application of commercial codes proved to be problematic as, unlike aerospace fans, industrial fans include electrical motors and other components from which the flow will invariably separate. Consequently, industrial fan designers found the application of commercial codes challenging. The decade from 2000 to 2010 was focused on developing techniques that would facilitate converged solutions that predicted the fans' performance characteristics over the stable part of their operating range with reasonable accuracy, using a practical computational effort. In this paper, we focus on elucidating aspects of the flow physics that one cannot easily study in a laboratory environment, discussing the challenges involved and the relative merits of the available modelling techniques. The paper ends with a discussion of the practical problems associated with the use of commercial codes in a development environment and finally the legislation that is driving the need for aerospace style computation methods.
Journal of Fluids Engineering, 2013
Volume 3: Controls, Diagnostics and Instrumentation; Cycle Innovations; Marine, 2010
... [7] proposed a stall-warning index (utilising ... when the signal-to-noise ratio (or, more pr... more ... [7] proposed a stall-warning index (utilising ... when the signal-to-noise ratio (or, more precisely, the instability signature-to-background noise ratio) is lowas is the case with regard to rotorstall-inception at ... [15] note that the relative positions of probes and blades influence visual ...
Journal of Engineering for Gas Turbines and Power, 2012
Volume 1A: Aircraft Engine; Fans and Blowers, 2014
Regulations require that industrial fans utilised in power generation, cement and steel applicati... more Regulations require that industrial fans utilised in power generation, cement and steel applications must operate as part of a process that produces erosive particles. Over time these erosive particles erode centrifugal fan impeller blades, changing the blade profile and consequently, degrading fan performance. To replace the eroded impellers, operators must shut down the process. If one must replace an impeller between scheduled maintenance intervals, the associated costs with lost production become significant. Consequently, the industrial fan community is interested in predicting the erosion, and ultimately, a fan impeller's in-service life when operating in an erosive environment. Industrial fan designers face challenges when attempting to predict impeller erosion. Industrial centrifugal fan impeller blades are routinely constructed from cambered plate, usually with backward or forward sweeping, with the inevitable consequence of separated flow regions. This separated flow is within a highly three dimensional flow-field making difficult an accurate prediction of the flow-field though an impeller with cambered plate blades. Assuming that one can accurately predict this three dimensional flow-field one must then go on to simulate the erosive particles' trajectory.
Periodica Polytechnica Mechanical Engineering, 2014
Application of computational methods to industrial fan design processes has progressed steadily o... more Application of computational methods to industrial fan design processes has progressed steadily over the past decade. The reducing cost of the computer hardware upon which codes run has brought the hardware within the reach of all industrial fan designers. However, the cost of commercially available codes remains high. Open source codes provide industrial fan designers with an alternative. The finite volume open-source solver OpenFOAM has been used by scholars to predict the performance of industrial centrifugal fans incorporating impeller blades constructed from cambered plate, but not by industrial fan designers. This paper presents a modelling approach which we developed for application as part of an industrial fan manufacturers order related design process. We compare numerical performance predictions with experimental results both at peak pressure and at peak efficiency conditions. As a further possible investigation, the simulated flow field is used to predict the patterns of erosion of the impeller.
Volume 4: Ceramics; Concentrating Solar Power Plants; Controls, Diagnostics and Instrumentation; Education; Electric Power; Fans and Blowers, 2013
ABSTRACT We report on a numerical study on the performance of an innovative axial flow fan for la... more ABSTRACT We report on a numerical study on the performance of an innovative axial flow fan for large tunnel ventilation. Taking a lead from a previous biomimetic analysis on the performance of the flippers of the humpback whale, this whale-fan was designed with sinusoidal-like leading edge that mimic the tubercles of the whale. We found that this provided a resistance to stall and improved lift recovery in post-stall operations. The sinusoidal profile of the leading edge allowed to control the distribution of vorticity on the suction surface of the blades and increase the stall margin of the device.The paper discusses the design methodology that was followed to correlate the sinusoidal shape of the leading edge of the blade with the desired vorticity distribution at the trailing edge that was needed to control separation.In the paper we show the results of numerical computations carried out with the finite volume open-source code OpenFOAM on the whale-fan as well as a baseline fan with straight leading edge. Reynolds Averaged Navier-Stokes equations for incompressible flow were solved with a non-linear (cubic) eddy-viscosity k-ε model that was found able to control the eddy viscosity distribution in order to account for anisotropy of Reynolds stresses and better reproduce the three-dimensional properties of the flow field.The paper shows the performance chart of the whale-fan, derived from numerical computations, and gives an insight of the fluid flow mechanisms that are generated by the sinusoidal leading edge on the suction surface of the fan. A comparison with the baseline fan with straight leading edge is provided in order to highlight how the shape of the leading edges affect the performance of the fan.
Journal of Vibration and Acoustics, 2011
Advances in Acoustics and Vibration, 2013
There are controversial requirements involved in developing numerical methodologies in order to c... more There are controversial requirements involved in developing numerical methodologies in order to compute the flow in industrial fans. The full resolution of turbulence spectrum in such high-Reynolds number flow configurations entails unreasonably expensive computational costs. The authors applied the study to a large unidirectional axial flow fan unit for tunnel ventilation to operate in the forward direction under ambient conditions. This delivered cooling air to the tunnel under routine operation, or hot gases at 400 ∘ C under emergency conditions in the event of a tunnel fire. The simulations were carried out using the open source code OpenFOAM, within which they implemented a very large eddy simulation (VLES) based on one-equation SGS model to solve a transport equation for the modelled (subgrid) turbulent kinetic energy. This subgrid turbulence model improvement is a remedial strategy in VLES of high-Reynolds number industrial flows which are able to tackle the turbulence spectrum's well-known insufficient resolution. The VLES of the industrial fan permits detecting the unsteady topology of the rotor flow. This paper explores the evolution of secondary flow phenomena and speculates on its influence on the actual load capability when operating at peakpressure condition. Predicted noise emissions, in terms of sound pressure level spectra, are also compared with experimental results and found to agree within the uncertainty of the measurements.
The Journal of the Acoustical Society of America, 2010
ABSTRACT Because of the global civil regulation concerning acoustic emission, the goal of the man... more ABSTRACT Because of the global civil regulation concerning acoustic emission, the goal of the manufacturers is to substantially decrease the noise radiated by the low-speed fans, without degrading their aerodynamic performance. One of the main goal to accomplish this target is the evaluation of the unsteady aerodynamic sources in the fan rotor responsible for the noise emission. An experimental analysis, based on a cause-effect method, was carried out and the results are presented in this paper. The process focuses on the experimental comparison between the novel prototypes of a family of low-speed fans and enabled the evaluation of the noise sources in the rotor near-field domain. The near-field aerodynamic sources accounted in this work correspond to the zones with high pressure fluctuations amplitude, located in the wake region of the exhaust flow. The sources were measured along the rotor radius and then correlated with the noise emitted by the fan at the far-field domain, using a Fourier based methodology. The analysis was carried out looking at the cross-spectra polar form using the phase shift as revealing tool for aerodynamic noise sources. The results were compared to evaluate the merit of the aero-acoustic performance of each prototype.
Journal of Engineering for Gas Turbines and Power, 2011
... stress, related to the change from normal operation to rotating stall, with a relatively smal... more ... stress, related to the change from normal operation to rotating stall, with a relatively small change in measured unsteady pressure over the fan-blade tip. The small changes in measured unsteadypressure result in traditional fan and compressor stall-warning systems being ...
Periodica Polytechnica Mechanical Engineering, 2013
Journal of Fluids Engineering, 2013
ABSTRACT In this paper we discuss a computational method focused on the prediction of unsteady ae... more ABSTRACT In this paper we discuss a computational method focused on the prediction of unsteady aerodynamics, adequate for industrial turbomachinery. Here we focus on a single rotor device selected from a new family of large tunnel ventilation axial flow fans. The flow field in the fan was simulated using the open source code OPENFOAM, with a large-eddy simulation (LES) approach. The sub-grid scale (SGS) closure relied on a one-equation model, that requires us to solve a differential transport equation for the modeled SGS turbulent kinetic energy. The use of such closure was here considered as a remedial strategy in LES of high-Reynolds industrial flows, being able to tackle the otherwise insufficient resolution of turbulence spectrum. The results show that LES of the fan allows to predict the pressure rise capability of the fan and to reproduce the most relevant flow features, such as three-dimensional separation and secondary flows.
International Journal for Numerical Methods in Fluids, 2007
ABSTRACT The YZβ shock-capturing technique was introduced recently for use in combination with th... more ABSTRACT The YZβ shock-capturing technique was introduced recently for use in combination with the streamline-upwind/Petrov–Galerkin formulation of compressible flows in conservation variables. The YZβ shock-capturing parameter is much simpler than an earlier parameter derived from the entropy variables for use in conservation variables. In this paper, we propose to use the YZβ shock-capturing in combination with the variable subgrid scale (V-SGS) formulation of compressible flows in conservation variables. The V-SGS method is based on an approximation of the class of SGS models derived from the Hughes variational multiscale method. We evaluate the performance of the V-SGS and YZβ combination in a number of standard, 2D test problems. Compared to the earlier shock-capturing parameter derived from the entropy variables, in addition to being much simpler, the YZβ shock-capturing parameter yields better shock quality in these test problems. Copyright © 2007 John Wiley & Sons, Ltd.