scholarly journals Experimental study of the unsteady vibration signature for a Sirocco fan unit

2019 ◽  
Vol 39 (1) ◽  
pp. 129-148
Author(s):  
José González ◽  
Laura Delgado ◽  
Sandra Velarde-Suárez ◽  
Jesús M Fernández-Oro ◽  
Katia Mª Argüelles Díaz ◽  
...  
Keyword(s):  
Public Transportation ◽  
Real Data ◽  
Design Procedures ◽  
Flow Features ◽  
Vibration Signature ◽  
Working Parameters ◽  
Flow Variables ◽  
Economic Constraints ◽  
Sirocco Fan ◽  
Transportation Applications

The small forward-curved blades known as Sirocco fan units are very common and widespread solution for air conditioning used in public transportation applications, as buses or trains. The users quietness and comfort have become a main concerns in the automotive industry. For such kind of turbomachinery flow , the patterns becomes always highly 3D and unsteady, compromising the referred comfort, and setting the focus on the working flow variables. A mathematically exact solution for that flow, which would provide any required information on pressure or forces, is out of scope at the current engineering design processes. Nevertheless, some flow features and mechanical data are needed to progress in the frame of a modern industrial environment, involving maintenance protocols with important temporal and economic constraints for different design procedures. The correctness of a given maintenance protocol relies on its feasibility to handle a set of machine working parameters or variables, including a number of them as wide as possible. Doing so, a set of not-dangerous ranges for them can be established. Such ranges are often defined promoting a series of failures similar to real ones, when the machine is in its operative lifetime. In this paper and in order to establish proper working ranges for maintenance purposes, a series of failures have been experimentally tested for a Sirocco fan unit. Initially, real data from industry have been required and a list of main failures was made, including (1) impeller or rotor unbalance, (2) impeller channel obstruction and (3) blocked inlet. The failures are studied using a purified orbit diagram (POD) technique and a symmetrized dot pattern (SDP) technique. All four working conditions are studied for at least three different flow rates and, therefore, a deeper insight into the fan working parameters and options are made feasible. In the frame of the maintenance protocol, a full set of ranges for the considered failures has been obtained. Therefore, the present paper shows a novel possibility to enhance existing maintenance protocol using two advanced frequency-based techniques.

Application of RFID Technology in Public Transport Company

2014 ◽  
Vol 718 ◽  
pp. 143-149 ◽  
Author(s):  
Michal Balog ◽  
Erik Szilágyi ◽  
Dávid Marton
Keyword(s):  
Information Systems ◽  
Radio Frequency ◽  
Radio Frequency Identification ◽  
Public Transport ◽  
Public Transportation ◽  
Rfid Technology ◽  
Area Of Interest ◽  
Frequency Identification ◽  
Expected Benefits ◽  
Transportation Applications

Our aim is to deal with the application of RFID technology in real conditions. Increasing interest in Radio Frequency Identification and related numerous applications for increasing automation in information systems has become an area of ​​interest public transportation applications. The reason for the application of RFID technology is tracking entrance/exit of vehicles to or from the parking area. The main expected benefits arising out of the introduction of this system is considered to maximize efficiency in payments to external carriers parking operator for services related to the use of the bus park for a period of time.

Development and Evaluation of a Performance Estimation Methodology for Fans Operating Within Non-Homogeneous Inflow

2016 ◽  
Author(s):  
D. Schoenweitz ◽  
R. Schnell
Keyword(s):  
Boundary Layer ◽  
Design Process ◽  
Harmonic Balance ◽  
Harmonic Balance Method ◽  
Computation Time ◽  
Performance Estimation ◽  
Simulation Methods ◽  
Design Procedures ◽  
Single Passage ◽  
Flow Features

The design process of modern aircraft engines extensively makes use of computational fluid dynamics (CFD). During the design process fan, compressor and turbine stages are typically evaluated using single passage CFD-simulations. For the design of an inlet distortion tolerant fan, the inhomogeneity of the inflow in circumferential direction does not allow the application of periodic boundary conditions and hence single passage simulations. Accordingly transient full annulus simulations have to be applied to correctly resolve the underlying physical interactions. The associated computation time for such a high fidelity simulation prohibit its application in today’s design procedures. This paper compares the simulation results of the ingestion of a mild and generic fuselage boundary layer of a blended wing body aircraft into an UHBR engine on the basis of four different simulation methods. The four different simulations include: transient full annulus CFD, Harmonic Balance frequency domain based CFD, steady full annulus CFD (Frozen Rotor) and steady single passage CFD for each blade passage. The results of the simulations are assessed using a newly developed stream tube based post-processing procedure. For the ingestion of the fuselage boundary layer the four numerical setups result in different aerodynamic conditions in the fan stage. For different aerodynamic measures different discrepancies are encountered for the different simulation methods. While the Harmonic Balance method can reproduce most features well, the simpler models overestimate the variations in the different flow features.

Influence of Channel Geometry and Flow Variables on Cyclone Cooling of Turbine Blades

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
Martin Bruschewski ◽  
Christian Scherhag ◽  
Heinz-Peter Schiffer ◽  
Sven Grundmann
Keyword(s):  
Heat Transfer ◽  
Swirling Flow ◽  
Turbine Blades ◽  
Transfer Characteristic ◽  
Internal Cooling ◽  
Eddy Simulation ◽  
Magnetic Resonance Velocimetry ◽  
Swirl Generator ◽  
Flow Features ◽  
Flow Variables

A study examining the internal cooling of turbine blades by swirling flow is presented. The sensitivity of swirling flow is investigated with regard to Reynolds number, swirl intensity, and the common geometric features of blade-cooling ducts. The flow system consists of a straight and round channel that is attached to a swirl generator with tangential inlets. Different orifices and 180-deg bends are employed as channel outlets. The experiments were carried out with magnetic resonance velocimetry (MRV) for which water was used as flow medium. As the main outcome, it was found that the investigated flows are highly sensitive to the conditions at the channel outlet. However, it was also discovered that for some outlet geometries the flow field remains the same. The associated flow features a favorable topology for heat transfer; the majority of mass is transported in the annular region close to the channel walls. Together with its high robustness, it is regarded as an applicable flow type for the internal cooling of turbine blades. A large eddy simulation (LES) was conducted to analyze the heat transfer characteristic of the associated flow for S0=3 and Re=20,000. The simulation showed an averaged Nusselt number increase of factor 4.7 compared to fully developed flow. However, a pressure loss increase of factor 43 must be considered as well.

scholarly journals Multivariate Modeling to handle Urban Air Pollution Data observed trough Vehicular Sensor Networks

2021 ◽  
Author(s):  
Israel L. C. Vasconcelos ◽  
André L. L. Aquino
Keyword(s):  
Sensor Networks ◽  
Air Quality ◽  
Public Transportation ◽  
Urban Air Pollution ◽  
Real Data ◽  
Environmental Modeling ◽  
Urban Environments ◽  
Spatial Behavior ◽  
Sensor Nodes ◽  
Interdisciplinary Assessment

This work presents an interdisciplinary assessment that looks in-depth at the tracking of air quality in urban environments. The proposed application takes advantage of Vehicle Sensor Networks (VSN) by embedding sensor nodes to public transportation, spreading the sampling activity through different places visited during the route. We perform environmental modeling based on real data collected from the city of São Paulo, considering the multivariate spatial behavior of five different air pollutants from fossil-fueled vehicles (CO, O3, PM10, NO2 and SO2) simultaneously while it also varies in time. Finally, our VSN-based approach showed an improvement of 126 times lower error and 11 times higher coverage about conventional monitoring with air quality stations.

Flow Analysis and Deterministic Decoupling in a Squirrel Cage Fan

2011 ◽  
Author(s):  
Jesu´s Manuel Ferna´ndez Oro ◽  
Sandra Velarde-Sua´rez ◽  
Israel Guerras Colo´n ◽  
Katia M. Argu¨elles Di´az ◽  
Jose´ Gonza´lez
Keyword(s):  
Flow Rate ◽  
Flow Analysis ◽  
Internal Flow ◽  
Centrifugal Fan ◽  
Practical Applications ◽  
Operating Modes ◽  
Operation Conditions ◽  
Squirrel Cage ◽  
Flow Features ◽  
Working Parameters

Squirrel cage fans are often used as blowers for automobile applications or for small industrial equipment. The flow in this kind of fans happens to be quite complex and with unsteady features, that makes it quite difficult to be studied. In particular, unsteady flow separation at the machine inlet or at the impeller blades and a variety of flow induced vibrations is found for most of the operation conditions. The deterministic stress analysis becomes an interesting tool in analyzing the main flow features from an existing numerical model. In this paper, the analysis of the internal flow and the periodic phenomena resulting from a deterministic study is intended. To accomplish this goal, a series of numerical routines were performed for different flow rates, including also failing operating modes of the fans (blocked inlets as a typical problem for this type of arrangements). The squirrel cage fan studied is a small centrifugal fan with a twin impeller configuration, each with 23 forward curved blades. The blades chord is 0.013 m and each impeller has a diameter of 0.08 m and a width of 0.09 m. The performance curves (head, power and efficiency versus flow rate) was obtained numerically in previous works and confirmed experimentally in normalized test campaigns. These tests have shown a nominal flow rate at around 352 m3/h and a specific speed ns = 1.9. The main goal of the paper consists on the evaluation of the non-uniformities induced by the volute tongue over the blade to blade distributions within the impeller. As a consequence, fluctuation levels in the blade loadings, derived from deterministic non-uniformities can be provided in the relative frame of reference. The practical applications of the conclusions do imply a progress in the knowledge of the working parameters for machines that affect in a direct way to the passengers comfort.

scholarly journals Performance of Overset Mesh in Modeling the Wake of Sharp-Edge Bodies

Computation ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 66
Author(s):  
Suyash Verma ◽  
Arman Hemmati
Keyword(s):  
Reynolds Number ◽  
Reynolds Numbers ◽  
Sharp Edge ◽  
Solution Technique ◽  
Viscous Effects ◽  
Surface Pressure Distribution ◽  
Flow Features ◽  
Background Grid ◽  
High Reynolds ◽  
Flow Variables

The wake dynamics of sharp-edge rigid panels is examined using Overset Grid Assembly (OGA) utilized in OpenFOAM, an open-source platform. The OGA method is an efficient solution technique based on overlap of a single or multiple moving grids on a stationary background grid. Five test cases for a stationary panel at different angle of attack are compared with available computational data, which show a good agreement in predicting global flow variables, such as mean drag. The models also provided accurate results in predicting the main flow features and structures. The flow past a pitching square panel is also investigated at two Reynolds numbers. The study of surface pressure distribution and shear forces acting on the panel suggests that a higher streamwise pressure gradient exists for the high Reynolds number case, which leads to an increase in lift, whereas the highly viscous effects at low Reynolds number lead to an increased drag production. The wake visualizations for the stationary and pitching motion cases show that the vortex shedding and wake characteristics are captured accurately using the OGA method.

scholarly journals Design and Implementation of Reduced Grid Impact Charging Station for Public Transportation Applications

2021 ◽  
Vol 12 (1) ◽  
pp. 28 ◽  
Author(s):  
Marco di Benedetto ◽  
Fernando Ortenzi ◽  
Alessandro Lidozzi ◽  
Luca Solero
Keyword(s):  
Energy Storage ◽  
Public Transportation ◽  
Design Procedure ◽  
Control Software ◽  
Electrical Grid ◽  
Charging Station ◽  
Fast Charging ◽  
Electromechanical Energy ◽  
And Control ◽  
Transportation Applications

This paper deals with the complete design procedure, implementation and control software realization for a multi-converter charging station with reduced grid impact due to local electromechanical energy storage. In particular, energy storage is accomplished by a dedicated flywheel designed and built for this purpose. The proposed charging station was designed for ultra-fast charging procedures presenting a strongly reduced impact on the electrical grid. Modes of operations are described with reference to pure electric buses in public transportation applications.

Sign in / Sign up

Export Citation Format

Share Document