Numerical Simulation of Unsteady Moist-Air Flows Through Whole-Annulus Rotor Blade Rows in Transonic Compressor

2019 ◽  
Author(s):  
Shota Moriguchi ◽  
Takuro Endo ◽  
Hironori Miyazawa ◽  
Takashi Furusawa ◽  
Satoru Yamamoto
Keyword(s):  
Numerical Simulation ◽  
Latent Heat ◽  
Rotor Blade ◽  
Droplet Evaporation ◽  
Rotor Blades ◽  
Moist Air ◽  
Uniform Temperature ◽  
Unsteady Forces ◽  
Transonic Compressor ◽  
Flow Through

Abstract In this study, we numerically investigated moist-air flow through the transonic compressor rotors of NASA Rotor 37, assuming whole-annulus rotor blade rows and non-uniform inlet wetness. This is an extension of our previous study, which assumed only a single passage and uniform inlet wetness. The amount of water droplets streaming into the compressor was changed in circumferentially non-uniform inlet condition. Numerical results indicated that non-uniform inlet wetness induced non-uniform temperature in the passages due to absorption of latent heat by droplet evaporation. Moreover, shock locations varied, depending on the local amount of wetness. Furthermore, turning angles of the flow and torque on the rotor blades were influenced by the wetness. Therefore, unsteady forces on the rotor blades were resultantly obtained by considering non-uniform inlet wetness conditions.

3D Unsteady Forces of the Transonic Flow Through a Turbine Stage With Vibrating Blades

2002 ◽  
Author(s):  
Romuald Rza˛dkowski ◽  
Vitaly Gnesin
Keyword(s):  
Transonic Flow ◽  
Gas Flow ◽  
Element Model ◽  
Ideal Gas ◽  
Rotor Blades ◽  
Turbine Stage ◽  
Unsteady Forces ◽  
Outer Flow ◽  
Natural Modes ◽  
Flow Through

Numerical calculations of the 3D transonic flow of an ideal gas through turbomachinery blade rows moving relatively one to another with taking into account the blades oscillations is presented. The approach is based on the solution of the coupled aerodynamic-structure problem for the 3D flow through the turbine stage in which fluid and dynamic equations are integrated simultaneously in time, thus providing the correct formulation of a coupled problem, as the blades oscillations and loads, acting on the blades, are a part of solution. An ideal gas flow through the mutually moving stator and rotor blades with periodicity on the whole annulus is described by the unsteady Euler conservation equations, which are integrated using the explicit monotonous finite-volume difference scheme of Godunov-Kolgan and moving hybrid H-H grid. The structure analysis uses the modal approach and 3D finite element model of a blade. The blade motion is assumed to be constituted as a linear combination of the first natural modes of blade oscillations with the modal coefficients depending on time. The algorithm proposed allows to calculate turbine stages with an arbitrary pitch ratio of stator and rotor blades, taking into account the blade oscillations by action of unsteady loads caused both outer flow nonuniformity and blades motion. There has been performed the calculation for the stage of the turbine with rotor blades of 0.765 m. The numerical results for unsteady aerodynamic forces due to stator-rotor interaction are compared with results obtained with taking into account the blades oscillations.

Unsteady Forces Acting on the Rotor Blades and Shaft in the Control Stage for Different Steam Admission Variants

2010 ◽  
Author(s):  
Romuald Rza˛dkowski ◽  
Marek Solin´ski
Keyword(s):  
Rotor Blade ◽  
Gas Flow ◽  
Low Frequency ◽  
Ideal Gas ◽  
Operating Conditions ◽  
Rotor Blades ◽  
Unsteady Forces ◽  
Control Stage ◽  
Start Up ◽  
Steam Admission

This paper concerns the unsteady high- and low-frequency excitation forces acting on the rotor blades and shaft in the control stage of a 200 MW steam turbine. An ideal gas flow through mutually moving stator and rotor blades was described in the form of unsteady Euler conservation equations, which were integrated using the Godunov-Kolgan explicit monotonous finite-volume difference scheme and a hybrid H-H grid. The effect of rotor blade mistuning on the unsteady forces acting on both the blades and the shaft was examined. Four different control stage steam admission variants were analysed. The actual levels of the stationary components of particular forces were determined by changes in the operating conditions of individual nozzle segments. Different mistuning variants generated different distributions of unsteady rotor blade force harmonics. The presented results show that the first harmonic does not always dominate the spectrum. When considering forces acting on the rotor blades and shaft, there exists an optimal procedure of turbine start-up.

scholarly journals Study of the Effect of Centrifugal Force on Rotor Blade Icing Process

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Zhengzhi Wang ◽  
Chunling Zhu
Keyword(s):  
Numerical Simulation ◽  
Centrifugal Force ◽  
Rotor Blade ◽  
Flow Direction ◽  
Three Dimensional ◽  
Simulation Method ◽  
Two Phase ◽  
Numerical Simulation Method ◽  
Calculation Results ◽  
Flow Field Characteristics

In view of the rotor icing problems, the influence of centrifugal force on rotor blade icing is investigated. A numerical simulation method of three-dimensional rotor blade icing is presented. Body-fitted grids around the rotor blade are generated using overlapping grid technology and rotor flow field characteristics are obtained by solving N-S equations. According to Eulerian two-phase flow, the droplet trajectories are calculated and droplet impingement characteristics are obtained. The mass and energy conservation equations of ice accretion model are established and a new calculation method of runback water mass based on shear stress and centrifugal force is proposed to simulate water flow and ice shape. The calculation results are compared with available experimental results in order to verify the correctness of the numerical simulation method. The influence of centrifugal force on rotor icing is calculated. The results show that the flow direction and distribution of liquid water on rotor surfaces change under the action of centrifugal force, which lead to the increasing of icing at the stagnation point and the decreasing of icing on both frozen limitations.

Enhanced vortex stability in trapped vortex combustor

2010 ◽  
Vol 114 (1155) ◽  
pp. 333-337 ◽  
Author(s):  
S. Vengadesan ◽  
C. Sony
Keyword(s):  
Numerical Simulation ◽  
Vortex Flow ◽  
Cavity Size ◽  
Vortex Stability ◽  
Cold Flow ◽  
Air Jets ◽  
Passive Flow ◽  
Flow Through ◽  
Trapped Vortex ◽  
Driver Air

Abstract The Trapped Vortex Combustor (TVC) is a new design concept in which cavities are designed to trap a vortex flow structure established through the use of driver air jets located along the cavity walls. TVC offers many advantages when compared to conventional swirl-stabilised combustors. In the present work, numerical investigation of cold flow (non-reacting) through the two-cavity trapped vortex combustor is performed. The numerical simulation involves passive flow through the two-cavity TVC to obtain an optimum cavity size to trap stable vortices inside the second cavity and to observe the characteristics of the two cavity TVC. From the flow attributes, it is inferred that vortex stability is achieved by circulation and the vortex is trapped inside when a second afterbody is added.

Stefan Number-Insensitive Numerical Simulation of the Enthalpy Method for Stefan Problems Using the Space-Time Conservation Element and Solution Element Method

2004 ◽  
Author(s):  
Anahita Ayasoufi ◽  
Theo G. Keith ◽  
Ramin K. Rahmani
Keyword(s):  
Numerical Simulation ◽  
Phase Change ◽  
Numerical Simulations ◽  
Latent Heat ◽  
Space Time ◽  
Enthalpy Method ◽  
Stefan Problems ◽  
Stefan Number ◽  
Original Scheme ◽  
Solution Element

An improvement is introduced to the conservation element and solution element (CE/SE) phase change scheme presented previously. The improvement addresses a well known weakness in numerical simulations of the enthalpy method when the Stefan number, (the ratio of sensible to latent heat) is small (less than 0.1). Behavior of the improved scheme, at the limit of small Stefan numbers, is studied and compared with that of the original scheme. It is shown that high dissipative errors, associated with small Stefan numbers, do not occur using the new scheme.

Analysis of the Stress Intensity of Rotor Blade in Hydraulic Retarder

2011 ◽  
Vol 179-180 ◽  
pp. 1453-1458
Author(s):  
Jun Yan
Keyword(s):  
Stress Intensity ◽  
Coordinate Transformation ◽  
Rotor Blade ◽  
Distribution Functions ◽  
Rotor Blades ◽  
Fea Model ◽  
Numeric Simulation ◽  
Braking Torque ◽  
Flow Pressure ◽  
Hydraulic Retarder

Based on CFD numeric simulation for hydraulic retarder under full-filled condition, the pressure distribution functions of the rotor blades surfaces are approached by coordinate transformation and surface fitting. Through the APDL program, loads which involved not only centrifugal force but also flow pressure are loaded on the FEA model according to the approximating pressure functions. The FEA model is solved and the blades strength is analyzed more accurately. Noted moment and speed, that is respectively 4000 N • m and 1343rpm, is determined under the promise of blade strength, and controlling strategy is made that constant braking torque shoud be carried out when speed is higher than noted value .

Numerical Simulation of Ethanol−Water−NaCl Droplet Evaporation

2010 ◽  
Vol 49 (12) ◽  
pp. 5631-5643 ◽  
Author(s):  
Xingmao Jiang ◽  
Timothy L. Ward ◽  
Frank van Swol ◽  
C. Jeffrey Brinker
Keyword(s):  
Numerical Simulation ◽  
Droplet Evaporation
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