scholarly journals The simulation of gas-dynamic characteristics of centrifugal compressors in turbo-expander units

2019 ◽  
Vol 124 ◽  
pp. 01008 ◽  
Author(s):  
A. Rekstin ◽  
V. Semenovskiy ◽  
K. Soldatova ◽  
Y. Galerkin ◽  
K. Sokolov
Keyword(s):  
Dynamic Characteristics ◽  
Rate Coefficient ◽  
Technical Specification ◽  
Design Parameters ◽  
Centrifugal Compressors ◽  
Gas Dynamic ◽  
Flow Rate Coefficient ◽  
Delivery Pressure ◽  
Turbo Expander ◽  
Total Capacity

Prof. Y. Galerkin and his team have developed and completed designs of 19 single-stage centrifugal compressors for turbo-expander packaged units applying Universal Modeling Method for the company “Turbokholod JSC” since 2005. The most powerful compressor is 6500 kW. The highest delivery pressure is 12 MPa. One hundred fifteen turbo-expander packaged units with total capacity 400 000 kW were manufactured, installed and were in operation in December 2018. The gas-dynamic characteristics of compressors comply with technical specification when operated within given range of initial temperatures and initial and final pressures up to 16 combinations for some compressors. The dimensionless characteristics of the compressor stages vary within the range of design parameters: flow rate coefficient 0.0278-0.0697, loading factor 0.43-0.71. The simulation of gas-dynamic characteristics of one of the designed compressors by the newest version of mathematical model is presented as an example, demonstrating the simulation features and effectiveness.

scholarly journals Issues of gas dynamic characteristics modeling: a study on a centrifugal compressor model stage

2019 ◽  
Vol 140 ◽  
pp. 06003 ◽  
Author(s):  
Aleksey Borovkov ◽  
Igor Voinov ◽  
Yuri Galerkin ◽  
Aleksandr Nikiforov ◽  
Maksim Nikitin ◽  
...  
Keyword(s):  
Flow Rate ◽  
Centrifugal Compressor ◽  
Rate Coefficient ◽  
Design Flow ◽  
Maximum Efficiency ◽  
Design Parameters ◽  
Gas Dynamic ◽  
Flow Rate Coefficient ◽  
Sst Turbulence Model ◽  
Problem Laboratory

The paper presents the results of CFD-calculations of a centrifugal compressor stage with a high-pressure 3D impeller and a vaneless diffuser. The stage was designed by Prof. A. M. Simonov in the Problem Laboratory of Compressor LPI according to the following design parameters: flow rate coefficient 0.080, loading factor 0.74, and the relative Mach number 0.78. Two design grids were used: 2.4 and 4.4 million cells for the sector with one blade. The entire stage was calculated with a sparser grid. Special “Stage” interface conditions are used to interface the gas-dynamic parameters at the boundary regions. The SST turbulence model was used in the calculations. The results of efficiency characteristics and work coefficient comparison showed the following: in design flow rate all three variants of the calculation overstate the loading factor by 14.3%; the calculated characteristics of polytrophic work coefficient in the staging of 360 degrees are closest to the experimental characteristics, but the absolute value is greater than 12% at a flow rate coefficient of 0.085; the maximum calculated efficiency of a stage (the circle of 360 degrees) is almost equal to the measured maximum efficiency.

scholarly journals Verification of a simplified mathematical model of centrifugal compressor stages

2019 ◽  
Vol 124 ◽  
pp. 01007 ◽  
Author(s):  
A. Rekstin ◽  
K. Soldatova ◽  
Y. Galerkin ◽  
E. Popova
Keyword(s):  
Flow Rate ◽  
Centrifugal Compressor ◽  
Rate Coefficient ◽  
Similarity Criteria ◽  
Low Flow ◽  
Design Parameters ◽  
Rate Model ◽  
Modelling Method ◽  
Flow Rate Coefficient ◽  
Measured Efficiency

To calculate the efficiency of a centrifugal compressor, it is sufficient to know the design parameters and similarity criteria: flow rate coefficient, loading factor, relative hub ratio, Mach number. The effect of the inlet nozzle and the diffuser type is also taken into account. The original simplified model was successfully used for calculation of compressors’ candidates in computer programs of the Universal Modelling Method. Recently, the model has undergone significant revision and been remade. The modernized model is used in the program for primary design of centrifugal compressors. The authors verified the new model, comparing the calculated efficiency with the measured efficiency of several dozens of model stages 21CV family and low flow rate model stages. In total, calculations were carried out for more than thirty model stages. The range of design parameters of analysed model stages is quite wide: flow rate coefficient 0.00564 – 0.0676; loading factor 0.384 – 0.742; hub ratio 0.258 – 0.466.

scholarly journals Design of high efficiency centrifugal compressors stages

2018 ◽  
Vol 54 (5) ◽  
pp. 4-9
Author(s):  
M. Kalinkevych ◽  
V. Ihnatenko ◽  
O. Bolotnikova ◽  
O. Obukhov
Keyword(s):  
Velocity Distribution ◽  
Dynamic Characteristics ◽  
Gas Flow ◽  
High Efficiency ◽  
Initial Pressure ◽  
Modern Trend ◽  
Centrifugal Compressors ◽  
Gas Dynamic ◽  
High Efficient ◽  
Loss Coefficients

The modern trend in compressor industry is an extension of the use of multi-shaft centrifugal compressors. Multi-shaft compressors have a number of advantages over single-shaft. The design of such compressors gives opportunity to use an axial inlet for all stages and select the optimum rotational speed for each pair of impellers, which, along with the cooling of the gas after each stage, makes possible to achieve high levels of efficiency. The design of high-efficiency centrifugal compressor stages can be performed on the basis of highly effective stage elements. Such elements are: impellers with spatial blades, vaned and channel diffusers with given velocity distribution. In this paper, impellers with axial-radial blades are considered. The blade profile is determined by the specified pressure distribution along the blade. Such design improves the structure of the gas flow in the interblade channels of the impeller, which leads to an increase in its efficiency. Characteristics of loss coefficients from attack angles for impellers were obtained experimentally. Vaned and channel diffusers, the characteristics of which are given in this article, are designed with the given velocity distribution along the vane. Compared to the classic type of diffuser, such diffusers have lower losses and a wider range of economical operation. For diffusers as well as for impellers, characteristics of loss coefficients from attack angles were obtained. High efficient impellers and diffusers and obtained gas-dynamic characteristics were used in the design of a multi-shaft compressor unit for the production of liquefied natural gas. The initial pressure of the unit is 3bar. The obtained characteristics of loss coefficients from attack angles for the considered impellers and diffusers make it possible to calculate the gas-dynamic characteristics of high-efficient centrifugal compressors stages. The high-efficient centrifugal compressors stages can be designed using high-efficient elements, such as: impeller with spatial blades and vaned diffuser with given velocity distribution.

scholarly journals Investigation of acoustic and gas dynamic characteristics of strongly swirled turbulent jets

2018 ◽  
Vol 980 ◽  
pp. 012017
Author(s):  
S Yu Krasheninnikov ◽  
VP Maslov ◽  
AK Mironov ◽  
PD Toktaliev
Keyword(s):  
Dynamic Characteristics ◽  
Turbulent Jets ◽  
Gas Dynamic

Development of High-Speed Response Electromagnetic Linear Actuator Using for Pneumatic Control Valve

2014 ◽  
Vol 532 ◽  
pp. 41-45 ◽  
Author(s):  
Myung Jin Chung
Keyword(s):  
Optimal Design ◽  
Dynamic Characteristics ◽  
High Speed ◽  
Design Method ◽  
Control Valve ◽  
Design Parameters ◽  
Linear Actuator ◽  
Analytic Model ◽  
Electromagnetic Linear Actuator ◽  
Quadratic Programming Method

Analytic model of electromagnetic linear actuator in the function of electric and geometric parameters is proposed and the effects of the design parameters on the dynamic characteristics are analyzed. To improve the dynamic characteristics, optimal design is conducted by applying sequential quadratic programming method to the analytic model. This optimal design method aims to minimize the response time and maximize force efficiency. By this procedure, electromagnetic linear actuator having high-speed characteristics is developed.

INFLUENCE OF GAS-DYNAMIC TESTING RIG PIPELINES MATERIAL ON THEIR DYNAMIC CHARACTERISTICS

2021 ◽  
pp. 118-125
Author(s):  
А.В. Саврико ◽  
С.Н. Лымич ◽  
К.В. Кружаев ◽  
В.С. Левин ◽  
А.В. Москвичев
Keyword(s):  
Flow Rate ◽  
Dynamic Characteristics ◽  
Dynamic Testing ◽  
Analytical Calculation ◽  
Working Fluid ◽  
Factors Affecting ◽  
Pressure Losses ◽  
Steel Pipes ◽  
Gas Dynamic ◽  
Friction Pressure

Приведено исследование зависимости газодинамических характеристик стенда от применяемого материала трубопровода. Oсновополагающими факторами, влияющими на работоспособность стенда, являются выходные параметры - давление и расход рабочего тела, которые напрямую зависят от потерь давления на трение, создаваемого элементами стенда. Для оценки степени влияния материалов на потери стенда выбраны два вида труб: полипропиленовые и металлические. Аналитические расчёты потери давления рассматриваемых трубопроводов из различного материала показали, что трубопроводы из полипропилена предпочтительнее. Однако при проведении эксперимента получены противоположные данные, которые показали, что в полипропиленовых магистралях возможно присутствие значительного количества диафрагм: в местах пайки труб, образовавшихся в процессе изготовления. Именно этот факт способствует существенному повышению значений сопротивлений в полипропиленовых трубопроводах на 20 % по сравнению со стальными трубами, где диафрагмы отсутствуют. В результате проведения исследования был введен коэффициент, учитывающий влияние диафрагм полипропиленового трубопровода при аналитическом расчете на сопротивление. Для сохранения более точных снимаемых значений с газодинамических стендов целесообразнее использовать трубопроводы из металла, в которых рассчитать потери возможно с отклонениями до 3 % Here we give the study of the dependence of the gas-dynamic characteristics of the stand on the pipeline material used. The fundamental factors affecting the performance of the stand are the output parameters-the pressure and flow rate of the working fluid, which directly depend on the friction pressure losses created by the elements of the stand. To assess the degree of influence of materials on the losses of the stand, we selected two types of pipes: polypropylene and metal. Analytical calculations of the pressure loss of the considered pipelines made of various materials have shown that pipelines made of polypropylene are preferable. However, during the experiment, we obtained the opposite data, which showed that a significant number of diaphragms may be present in polypropylene pipelines: in the places of soldering of pipes formed during the manufacturing process. This fact contributes to a significant increase in the resistance values in polypropylene pipelines by 20 % compared to steel pipes, where there are no diaphragms. As a result of the study, we introduced a coefficient that takes into account the influence of polypropylene pipeline diaphragms in the analytical calculation of resistance. To preserve more accurate values taken from gas-dynamic stands, it is more expedient to use metal pipelines in which it is possible to calculate losses with deviations of up to 3 %

Dynamic Characteristics Analysis of NuScale in Frequency Domain

2021 ◽  
Author(s):  
Jingrui Yang ◽  
Qian Ma ◽  
Lingtong Han ◽  
Peiwei Sun
Keyword(s):  
Frequency Domain ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Dynamic Characteristics ◽  
Water Desalination ◽  
Design Parameters ◽  
Mechanism Analysis ◽  
Secondary Loop ◽  
Calculation Results

Abstract NuScale is a small nuclear reactor that relies on natural circulation. Its modular production and inherent safety can not only be used to generate electricity in some remote areas, but also provide energy for water desalination and regional heating. However, the dynamic characteristics of the NuScale are different from those of the traditional PWRs because of its passive characteristic. Therefore, it is necessary to study and analyze the system dynamic characteristics of NuScale. The NuScale PWR model is established based on MATLAB&Simulink. It includes point-reactor kinetics model with six groups delayed neutrons, coolant system and steam generator system. The model is established based on the conservation equations of mass, energy and momentum. And the correctness of the model is verified by the comparison between the steady-state calculation results and the design parameters. Transient calculation results are verified by mechanism analysis. To evaluate the dynamic characteristics of NuScale, the sine function changes with different frequencies in reactor reactivity and feedwater mass flow rate are introduced. The amplitude and phase responses of reactor power, secondary loop steam pressure, secondary loop mass flow rate, secondary loop steam temperature, and coolant average temperature are recorded. Then the Bode plot can be drawn with amplitude and phase responses in different frequencies. To evaluate the NuScale dynamic characteristics, frequency domain analysis is performed.

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