Unsteady Loading of Rotor Blades by High Pressure Air Injection

2009 ◽  
Author(s):  
John N. Chi
Keyword(s):  
High Pressure ◽  
Computational Fluid Dynamic ◽  
Rotor Blade ◽  
Fluid Dynamic ◽  
Air Injection ◽  
Cfd Model ◽  
One Dimensional ◽  
Transonic Compressor ◽  
Aerodynamic Loading ◽  
Transonic Rotor

A gas turbine engine consists of three primary components: a compressor, a combustion chamber, and a turbine. The operating range, performance, and reliability of gas turbine engines are limited by aerodynamic instabilities that occur in the compressor at low mass flow rates. Two of such compressor instabilities are rotating stall and surge. The stabilization of compression systems by means of active control has been demonstrated on several research compressors using different actuators such as inlet guide vanes, bleed valves, and air injection to manipulate the compressor flow field. This paper presents experimental and model simulated results of the steady and unsteady behaviors of air injection in high speed axial flow compressors that can be used for feasibility studies and control algorithm development. A control oriented model of the unsteady response of the transonic compressor blade rows to steady air injection is presented. This behavior was modeled by one-dimensional flow in a diffusing passage subject to a time varying inlet flow condition in the rotor relative reference frame. The one-dimensional model was then used to provide simplified input boundary conditions for a computational fluid dynamic (CFD) model that predicted aerodynamic loading on a transonic rotor blade due to steady air injection. The aerodynamic loading on a transonic rotor blade due to steady air injection were then simulated from the computational fluid dynamic (CFD) model. The simulation results for an evenly circumferentially spaced discrete number of jet actuators show that the fluctuating loading due to jet injection are non-sinusoidal and periodic. Total pressure, total temperature, and absolute flow angle survey measurements that map out the effect of high pressure air injection on a transonic compressor rotor for different levels of steady injection and different orientations are also presented.

scholarly journals Computational Fluid Dynamic Simulation of Single Bubble Growth under High-Pressure Pool Boiling Conditions

2016 ◽  
Vol 48 (4) ◽  
pp. 859-869 ◽  
Author(s):  
Janani Murallidharan ◽  
Giovanni Giustini ◽  
Yohei Sato ◽  
Bojan Ničeno ◽  
Vittorio Badalassi ◽  
...  
Keyword(s):  
High Pressure ◽  
Dynamic Simulation ◽  
Computational Fluid Dynamic ◽  
Bubble Growth ◽  
Fluid Dynamic ◽  
Pool Boiling ◽  
Computational Fluid Dynamic Simulation ◽  
Single Bubble

CHIMERA volume grid generation within the EROS code

2000 ◽  
Vol 214 (3) ◽  
pp. 125-141 ◽  
Author(s):  
C B Allen
Keyword(s):  
Computational Fluid Dynamic ◽  
Rotor Blade ◽  
Fluid Dynamic ◽  
Grid Generation ◽  
Design Tool ◽  
Software Project ◽  
Blade Design ◽  
Collaborative Project ◽  
Structured Grid ◽  
Research Institutes

The EROS (European ROtorcraft Software) project was a three-year, European Commission funded, collaborative project between research institutes, universities and industry, with the goal of producing a practical computational fluid dynamic (CFD)-based design tool for rotor blade design. The overlapping mesh, or CHIMERA, approach was adopted for structured grid generation within the project. The specifics of volume grid generation in GEROS, the EROS grid generator, are presented here. The capabilities and effectiveness of GEROS are demonstrated, and sample grids are shown for fixed-wing hovering rotor and forward-flight rotor cases.

Transonic Compressor Rotor Design Using Non-Monotonic Meanline Angle Distribution

2007 ◽  
Author(s):  
Zongjun Hu ◽  
Gecheng Zha ◽  
Matthew Montgomery ◽  
Thomas Roecken ◽  
John Orosa
Keyword(s):  
Mach Number ◽  
Rotor Blade ◽  
Angle Distribution ◽  
Stall Margin ◽  
Blade Passage ◽  
Transonic Compressor ◽  
Compressor Rotor ◽  
Rotor Design ◽  
Blade Section ◽  
Transonic Rotor

A non-monotonic meanline angle distribution technique with local negative camber is applied to a transonic rotor blade from the hub area to tip with the inlet Mach number varying from subsonic to low supersonic. The blade passage area is controlled by the non-monotonic meanline angle distribution, which results in reduced peak Mach number and weakened or removed shock wave. The negative camber is used downstream of the throat and hence it does not affect the flow passing capability of the blade section. The design point efficiency is significantly increased and the stall margin at part speed is also improved. Detailed results are given in the paper.

Improved Prediction of Indoor Contaminant Distribution for Entire Buildings

2002 ◽  
Author(s):  
Jinchao Yuan ◽  
Jelena Srebric
Keyword(s):  
Computational Fluid Dynamic ◽  
Fluid Dynamic ◽  
The Other ◽  
Zone Model ◽  
Cfd Model ◽  
Combined Model ◽  
Contaminant Distribution

This paper presents a study on improvements of multi-zone models for predicting building contaminant distribution by combining a multi-zone model with a Computational Fluid Dynamic (CFD) model. The motivation is to avoid the long computations in the CFD model that are required for predicting concentrations in entire buildings. Two cases are investigated using the combined model and the results are compared to reliable experimental or CFD data. The comparisons show that the combined model provides better results than the multi-zone model alone in one of the cases, while in the other no major improvements were observed. Further investigation and development of the combined model is needed.

A Multizone Model of an Economizer in a 600 MW Boiler Unit

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Wang Jizhou ◽  
Zhang Yanping ◽  
Li Yu ◽  
Huang Shuhong
Keyword(s):  
Steady State ◽  
Computational Fluid Dynamic ◽  
Fluid Dynamic ◽  
Computational Cost ◽  
Distribution Characteristics ◽  
Boiler Unit ◽  
Cfd Model ◽  
Distribution Parameters ◽  
Multizone Model ◽  
Operational Data

In this paper, a multizone model is developed to investigate the performance of an economizer under all conditions. The model primarily determines the economizer’s distribution parameters under all conditions with a small computational cost. Both the steady-state and dynamic behavior are calculated. These results are shown to be accurate and reliable using a computational fluid dynamic (CFD) model and the operational data obtained from a 600 MW boiler unit in Hubei province, China. Additionally, the model is used to predict the distribution characteristics during some fault conditions.

A CFD Approach to Fluid Dynamic Optimum Design of Steam Turbine Stages With Stator and Rotor Blades

2010 ◽  
Author(s):  
Xin Yuan ◽  
Tadashi Tanuma ◽  
Xiaofeng Zhu ◽  
Zhirong Lin ◽  
Daisuke Nomura
Keyword(s):  
High Pressure ◽  
Steam Turbine ◽  
Optimum Design ◽  
Rotor Blade ◽  
Fluid Dynamic ◽  
Rotor Blades ◽  
Turbine Stage ◽  
Tip Leakage ◽  
Pressure Steam ◽  
End Wall

An advanced aerodynamic design optimization system for steam turbine stages considering rotor blade tip leakage and blade end-wall non-axis-symmetric contouring has been developed. Using this system, fluid dynamic optimizations were carried out for a steam turbine stage with stator and rotor blades. The system includes parametric modeling of blade and end-wall contouring, evaluation system with in-house or package CFD software and optimization strategy module. The designs of rotor blade and hub end-wall surface in a typical large-scale high-pressure steam turbine stage were optimized in order to know this design optimization impact on enhancing the stage efficiency. Results show that: from the current well designed high pressure steam turbine stage, the demonstrated efficiency enhancement with the present optimum design is around 0.2% under consideration of rotor tip leakage. Design cycle could be greatly shortened by parallel optimization algorithm and cluster PC, and especially four days could be sufficient for an optimization with one thousand iterations on 20 CPUs of 2.0G cluster PC.

scholarly journals A Computational Fluid Dynamic Study of Developed Parallel Stations for Primary Fans

Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1607
Author(s):  
Juan Pablo Hurtado ◽  
Gabriel Reyes ◽  
Juan Pablo Vargas ◽  
Enrique Acuña
Keyword(s):  
Computational Fluid Dynamic ◽  
Energy Cost ◽  
Fluid Dynamic ◽  
Shock Pressure ◽  
Cfd Model ◽  
Blade Angle ◽  
Cfd Simulations ◽  
Pressure Losses ◽  
Operating Points ◽  
Over Time

A Computational fluid dynamic (CFD) model was developed considering three geometries for primary parallel fan stations that have already been developed, implemented, and are currently in operation within Chilean mines. To standardize the comparison, the same primary fan was used in all the simulations with a unique set of settings (speed, blade angle, and density). The CFD representation was used to determine the operating point per configuration and compare the performances in terms of airflow and pressure delivered. This approach allowed ranking primary fan station geometry based on resistance curve and energy consumption of the fan. This paper presents the results obtained through the CFD simulations and the corresponding primary fans operating points of each configuration: symmetrical branches (SB), overlap branches (OB), and run around (RA) bypass. The RA configuration was identified as the best-performing station geometry on the lowest frictional and shock pressure losses, highest airflow delivery, and lowest energy cost. The results are discussed, considering pressure, velocity, and vector contours to understand the fluid dynamics phenomena occurring inside the station. The capital cost involved in the development of each primary parallel station was considered in the analysis in addition to the energy cost to determine the economic configuration over time.

Damping of modal perturbations in solid rocket motors

2016 ◽  
Vol 120 (1231) ◽  
pp. 1425-1445 ◽  
Author(s):  
A.S. Iyer ◽  
V.K. Chakravarthy ◽  
S. Saha ◽  
D. Chakraborty
Keyword(s):  
Computational Fluid Dynamic ◽  
Fluid Dynamic ◽  
Sectional Area ◽  
Dynamic Simulations ◽  
Cross Sectional ◽  
Solid Rocket Motors ◽  
Rocket Motors ◽  
One Dimensional ◽  
Solid Rocket ◽  
High Length

ABSTRACTQuasi-one-dimensional (quasi-1D) tools developed for capturing flow and acoustic dynamics in non-segmented solid rocket motors are evaluated using multi-dimensional computational fluid dynamic simulations and used to characterise damping of modal perturbations. For motors with high length-to-diameter ratios (of the order of 10), remarkably accurate estimates of frequencies and damping rates of lower modes can be obtained using the the quasi-1D approximation. Various grain configurations are considered to study the effect of internal geometry on damping rates. Analysis shows that lower cross-sectional area at the nozzle entry plane is found to increase damping rates of all the modes. The flow-turning loss for a mode increases if the more mass addition due to combustion is added at pressure nodes. For the fundamental mode, this loss is, therefore, maximum if burning area is maximum at the centre. The insights from this study in addition to recommendations made by Blomshield(1)based on combustion considerations would be very helpful in realizing rocket motors free from combustion instability.

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