Calculation Of The Impellers Head Characteristics Of The Low-Flow Centrifugal Compressor Stages Based On Quasi-Three-dimensional inviscid And Viscous Methods

Abstract. The paper shows the results of calculation internal head characteristics of the intermediate low-flow centrifugal compressor stages impellers. The type of stages is used at the last stages of multistage centrifugal compressors of the high and ultrahigh pressure. Inviscid quasi-three-dimensional and viscous three-dimensional calculation methods are used. Numerical models of the objects of study represent the flow part of the impeller and the blade-free diffuser with width equal to the height of the blade at the output of the impeller. For a CFD calculation, two interfaces are considered: frozen rotor and stage. It is found that the most qualitative character has a viscous calculation with the Stage interface and inviscid quasi-three-dimensional calculation.

The Task Of Validation Of Gas-Dynamic Of Characteristics Of A Multistage Centrifugal Compressor, For A Natural Gas Booster Compressor Station

Abstract. The aim of this work is the validation study for the numerical modeling of characteristics of a multistage centrifugal compressor for natural gas. In the research process was the analysis used misyachna interfaces and software systems. The result revealed discrepancies between the simulated and experimental characteristics and outlined the future work plan.

Development of the virtual experimental bench on the basis of modernized research centrifugal compressor stage test unit with the 3D impeller.

Abstract. Design modernization of the centrifugal compressor stage test bench with three dimensional impeller blades was carried out for the possibility of holding a series of experimental studies of different 3D impeller models. The studies relates to the problem of joint work of the impeller and the stationary channels of the housing when carrying out works on modernization with the aim of improving the parameters of the volumetric capacity or pressure in the presence of design constraints. The object of study is the experimental single end centrifugal compressor stage with the 3D impeller. Compressor stage consists of the 3D impeller, vaneless diffuser (VLD), outlet collector — folded side scroll and downstream pipe. The drive is a DC motor 75 kW. The increase gear (multiplier) was set between the compressor and DC motor, gear ratio is i = 9.8. To obtain the characteristics of the compressor and the flow area the following values were measured: total pressure, static pressure, direction (angles) of the stream in different cross sections. Additional pneumometric probes on the front wall of the VLD of the test bench have been installed. Total pressure probes and foster holes for the measurement of total and static pressure by the new drainage scheme. This allowed carrying out full experimental studies for two elements of centrifugal compressor stage. After the experimental tests the comprehensive information about the performance of model stage were obtained. Was measured geometric parameters and the constructed virtual model of the experimental bench flow part with the help of Creo Parametric 3.0 and ANSYS v. 16.2. Conducted CFD calculations and verification with experimental data. Identifies the steps for further experimental and virtual works.

Моделирование нестационарных процессов в турбомашинах на основе нелинейно-гармонического NLH-метода с использованием суперкомпьютеров

Целью работы является апробация нелинейно-гармонического метода NLH (Non-linear harmonic), предназначенного для моделирования нестационарного аэродинамического взаимодействия ротора и статора в турбомашинах, отличающегося высокой скоростью вычислений в сравнении с подходами полномасштабного нестационарного расчёта течения. Расчеты нестационарных течений в турбомашинах относятся к классу вычислительно ресурсоемких задач и для решения реальных задач за приемлемое время требуется использование суперкомпьютеров. На кафедре «Компрессорной, вакуумной и холодильной техники» в целях апробации получены решения двухмерных и трёхмерных течений в турбомашинах с применением NLH метода, реализованного в программном комплексе NUMECAFine/Turbo. К настоящему времени проведено сравнение нестационарного течения со стационарным, получены картины течений и рассмотрен вопрос о консервативности параметров течения.

Multi-objective optimization for impeller shroud contour, the width of vane diffuser and the number of blades of the centrifugal compressor stage based on the CFD calculation

Abstract. The study presents the results of multi-objective optimization for a high flow centrifugal compressor stage with impeller pressure ratio П=1.3 and conditional flow rate coefficient Φ=0.108. The compressor stage includes an impeller with 3D backswept blades, a vane diffuser and an axial inlet. The goal of optimization is to increase polytropic efficiency and polytropic head ratio of the basic design. The CFD method is used to estimate compressor efficiency at rated duty. CAE optimization is applied based on the parametric optimization of impeller shroud contour and number of blades of the impeller and diffuser versus the original design. Parameterization of geometrics is also used to the width-ratio of vane diffuser in the range of b3/D2= 0.08-0.097. The study considers 52 cases of the optimization of impeller shroud contour and the number of blades in the search for the improved design. The optimization procedure uses the automatic generated computation grid and supplementary activation of solution to each design case. The numerical calculation for each case has been performed automatically by ANSYS CFX 14.5 soft application.  The optimization allowed to obtain the improved design with total polytropic efficiency increase by 1.58%  for the impeller and polytropic head coefficient increase by 0.58%. The polytropic efficiency and the polytropic head coefficient are calculated on the total parameters. The performance of the basic impeller has been exhaustibly validated by test records provided JSC “REPH ZAO”. The resulted error range does not exceed 5% over the performance map, except near surge point..


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