DEGREE OF REGENERATION OPTIMIZATION FOR CYCLES OF MICROGAS TURBINE PLANTS

2020 ◽  
Vol 3 ◽  
pp. 59-66
Author(s):  
A.V. DOLOGLONYAN ◽  
V.T. MATVIINKO
Keyword(s):  
Mathematical Model ◽  
Heat Exchanger ◽  
Surface Area ◽  
Hydraulic Resistance ◽  
Recovery Factor ◽  
Pressure Recovery ◽  
Area Optimization ◽  
Pressure Recovery Factor ◽  
The Mathematical Model ◽  
Regenerative Cycle

A consideration subject in article is the mathematical model of pressure recovery factor of microgas turbine plants (MGTP) regenerators which considers dependence of hydraulic resistance of the heat–exchanger on the its surface area. Optimization of a regenerative cycle of MGTP and a cycle with regeneration and the turbocompressor utilizer for the purpose of further increase in their profitability is performed. It is established that use of the offered model of pressure recovery factor on the air and gas side allows to find degree of regeneration heattechnical optimum. This model can be used at simplified and predesign of MGTP.

On the Improvement of Tool Life in Self-Piloting Drilling with External Chip Removal

1996 ◽  
Vol 210 (3) ◽  
pp. 243-250
Author(s):  
V P Astakhov ◽  
M O M Osman
Keyword(s):  
Mathematical Model ◽  
Hydraulic Resistance ◽  
Tool Life ◽  
Fluid Pressure ◽  
Comprehensive Analysis ◽  
Cutting Fluid ◽  
Experimental Comparison ◽  
Two Stage ◽  
The Mathematical Model ◽  
Chip Removal

This paper presents both the design and the method of grinding of self-piloting drills (SPDs) with external chip removal. The main advantage of the proposed SPDs over the standard SPDs is brought out using a comprehensive analysis of the SPD auxiliary flank design. The concept of increasing the cutting fluid pressure in the limited space between the tool flanks and the bottom of the hole being drilled by increasing the hydraulic resistance of the channel connecting this space and the chip removal passage is proposed. For the realization of the concept, the mathematical model for the auxiliary flank has been derived on the basis of the obtained condition for a free tool penetration into the workpiece. Using this model, the detailed grinding procedure for the proposed SPDs is explained. The two-stage experimental comparison of the standard and proposed SPDs shows that a significant improvement of tool life is achieved by using the proposed SPDs.

scholarly journals A Long-Term Analysis of the Possibility of Water Recovery for Hydroponic Lettuce Irrigation in Indoor Vertical Farm. Part 1: Water Recovery from Exhaust Air

2020 ◽  
Vol 10 (24) ◽  
pp. 8907 ◽  
Author(s):  
Anna Pacak ◽  
Anna Jurga ◽  
Paweł Drąg ◽  
Demis Pandelidis ◽  
Bartosz Kaźmierczak
Keyword(s):  
Mathematical Model ◽  
Heat Exchanger ◽  
Cross Flow ◽  
Transitional Period ◽  
Water Recovery ◽  
Air Conditioning System ◽  
Flow Heat ◽  
Stable Source ◽  
The Mathematical Model

This paper presents the characteristics of the operation of the system for recovery of water from exhaust air in moderate climates in the years 2012–2019. The proposed system for water recovery uses the phenomenon of condensation in a cross-flow heat exchanger operating as an element of the air conditioning system. The parameters of exhaust air behind the heat exchanger have been determined using a mathematical model of the so-called black box. The mathematical model considers the risk of the cross-freezing of the heat exchanger. The calculations carried out for variable parameters of external air during the analyzed period confirm that the system allows to cover the demand for water for lettuce irrigation during the cold and transitional period, which is a major part of the year. It has been noted that the effectiveness of the system is very high (av. 67.12% per year) due to the specific parameters of the internal air in which the lettuce must be grown and the need for continuous air exchange in such facilities. This means that air is a stable source of water recovery, where the recovery rate depends on the parameters of external air.

Verification of Control System by Physical Simulation

2014 ◽  
Vol 472 ◽  
pp. 389-393
Author(s):  
Wei Guo Yuan ◽  
Ya Bin Wang
Keyword(s):  
Mathematical Model ◽  
Control System ◽  
Heat Exchanger ◽  
Physical Simulation ◽  
Control System Design ◽  
Control Module ◽  
Heat Exchanger Design ◽  
Simulation And Control ◽  
And Control ◽  
The Mathematical Model

Control system is generally verified by experiment, some of which are too difficult or high-cost to implement, while physical simulation can be substituted for experiment to verify the effectiveness of control system. The study take the heat exchanger as an example to describe the process of verification by physical simulation: Choose FLOEFD and SIMULINK as the software of physical simulation and control system design, establish the mathematical model of heat exchanger, design control module, whose output is set as an input of FLOEFD, compare the result of physical simulation and SIMULINK, if they are similar, the control module is effective.

scholarly journals Обґрунтування моделі турбулентної в’язкості для дослідження характеристик співвісного гвинтовентилятора і вхідного пристрою ГТД

2021 ◽  
pp. 35-39
Author(s):  
Олег Володимирович Жорник ◽  
Ігор Федорович Кравченко ◽  
Михайло Михайлович Мітрахович ◽  
Олеся Валеріїна Денисюк
Keyword(s):  
Mathematical Modeling ◽  
Total Pressure ◽  
Turbulent Viscosity ◽  
Flight Test ◽  
Recovery Factor ◽  
Pressure Recovery ◽  
Recovery Coefficient ◽  
Transition Analysis ◽  
Total Pressure Recovery ◽  
Pressure Recovery Factor

The issues of substantiation of the most rational, based on adequacy, model of turbulent viscosity for mathematical modeling of the flow near the propfan and in the inlet of the turbine-propeller engine are considered. It was found that at present there is no universal turbulence model for determining the parameters of the boundary layer, energy loss in the flow, and laminar-turbulent transition. Analysis of the results of previous studies showed that there is a need to select and justify a turbulent viscosity model for each type of research object. The task of modeling the flow near the propfan and in the inlet device of the power plant was performed using the ANSYS CFX software product, which allows using various standard mathematical models and tools for modeling turbulent flow. The object of research is an annular axial inlet device, in front of which there is a coaxial propfan with two rows of propellers: the first row has eight blades, the second - six. 7 types of models of turbulent viscosity, which most fully describe the phenomena in the flow around the propfan and the inlet device, have been investigated: k-ωmodel; SSТ (shear stress transport) SST Transitional №1 Fully turbulence; SST Transitional №2 Specified Intermittency; SST Transitional №3 Gamma model; SST Transitional №4 Gamma theta model; SST Transitional №5 Intermittency. The results of mathematical modeling of the flow near the propfan and in the inlet device at the corresponding operating mode of the turbopropfan engine using the selected models of turbulent viscosity, the total pressure value in front of and behind the inlet device was obtained to determine the total pressure recovery coefficient in it and the value of the propfan thrust. The value of the recovery factor of the total pressure in the inlet device and the propfan thrust are compared with the flight test data of the prototype. An analysis of the comparison of the values of the total pressure recovery factor in the inlet device and the propfan thrust showed that the use of the SST Transitional №4 Gamma theta model allows obtaining the value of the total pressure recovery factor in the inlet device and the propfan thrust that is closest to the flight test results.

Growth of the total pressure recovery factor in a flow behind a shock wave emerging from a channel with concave corners in cross section

2003 ◽  
Vol 29 (5) ◽  
pp. 385-387 ◽  
Author(s):  
T. V. Bazhenova ◽  
V. V. Golub ◽  
A. L. Kotel’nikov ◽  
A. S. Chizhikov ◽  
M. V. Bragin
Keyword(s):  
Shock Wave ◽  
Cross Section ◽  
Total Pressure ◽  
Recovery Factor ◽  
Pressure Recovery ◽  
Total Pressure Recovery ◽  
Pressure Recovery Factor

Improving the Efficiency of a Hydro-Turbine System by Vortex Generators

2011 ◽  
Vol 354-355 ◽  
pp. 636-641 ◽  
Author(s):  
Hua Chen Pan ◽  
Shu Li Hong
Keyword(s):  
Working Conditions ◽  
Draft Tube ◽  
Vortex Generators ◽  
Recovery Factor ◽  
Pressure Recovery ◽  
Hydro Turbine ◽  
Turbine Performance ◽  
Pressure Recovery Factor ◽  
Inside Wall

This paper studies the effect of vortex generators on hydro-turbine working performances. The study was carried out on a hydro-turbine system provided by Waterpumps Oy, Finland. First, the performance of the hydro-turbine system was analyzed with a CFD solver under different working conditions. Then, the hydro-turbine performance was examined with several vortex generators installed uniformly on the inside wall of the draft tube near its inlet. The turbine system’s efficiencies were compared for cases with and without vortex generators. Results show that turbine performs better when there are vortex generators installed in the draft tube of which the pressure recovery factor is much higher.

Numerical Simulation and Experimental Validation of a Vertical U-Tube Ground Heat Exchanger

2013 ◽  
Vol 860-863 ◽  
pp. 709-714
Author(s):  
Yi Ke Gao ◽  
Yan Gao ◽  
Yong Yu ◽  
Xin Xing Lin
Keyword(s):  
Mathematical Model ◽  
Heat Exchanger ◽  
Temperature Distribution ◽  
Experimental Validation ◽  
Absolute Error ◽  
Energy Utilization ◽  
Heat Extraction ◽  
Ground Heat Exchanger ◽  
Ground Source ◽  
The Mathematical Model

Vertical U-tube ground heat exchanger (GHE) is a key component in geothermal energy utilization systems like ground source heat pump (GSHP). This paper used a two-dimensional transient mathematical model for predicting the heat extraction rate of a vertical U-tube GHE, which also took into account the temperature distribution under the ground. Furthermore the modelling predictions were validated using experimental data. The experimental validation on the model was performed in a GSHP system with a double U-tube GHE, which was of 55m depth. For temperature distribution under the ground, the absolute error and relative error between experiment and simulation are within 0.62°C and 3.71 %. Simulation results agreed well with the experimental results that validate the feasibility of the mathematical model.

scholarly journals Удосконалення характеристик кільцевого вхідного пристрою авіаційної силової установки з гвинтовентилятором

2021 ◽  
pp. 11-18
Author(s):  
Олег Володимирович Жорник ◽  
Ігор Федорович Кравченко ◽  
Михайло Михайлович Мітрахович
Keyword(s):  
Total Pressure ◽  
Influential Factor ◽  
Recovery Factor ◽  
Pressure Recovery ◽  
Input Device ◽  
Navier Stokes Equation ◽  
Element Analysis ◽  
Turboprop Engine ◽  
Pressure Recovery Factor ◽  
Full Pressure

The article considers the method of improving the characteristics of the ring inlet device, taking into account the influence of the propeller of an aircraft power plant with a turboprop engine. It is shown that increasing the total pressure loss in the inlet device by 5% increases, approximately, the specific fuel consumption by 3% and reduces engine thrust by 6%, and uneven flow at the inlet to the engine is the cause of unstable compressor of the turboprop engine. It is proposed to improve the characteristics of the input device by modifying the shape of its shell and channel. Evaluation of the influence of the shape of the shell and the channel of the annular axial VP on its main aerodynamic characteristics, taking into account the non-uniformity of the flow on the fan in the calculated mode of operation of the SU is carried out by calculating the full pressure recovery factor. The object of the study is an annular axial input device in front of which is a coaxial fan turboprop fan. The process of modeling the influence of the shape of the shell and the channel on the recovery factor of total pressure, circular and radial non-uniformity of the flow through the input device is implemented in the software system of finite element analysis ANSYS CFX. Geometric models of coaxial screw fan, fairing and inlet device are built in ANSYS SpaceClaim and transferred using the built-in import function in ANSYS Workbench. Block-structured grid models of air propellers of the first and second rows of the fan in the amount of 1.9 million, fairing and inlet device, in the amount of 3.9 million, are built in the ANSYS TurboGrid environment. The standard Stern (Shear Stress Transport) Gamma Theta Transition was used to close the Navier-Stokes equation system. Based on the results of mathematical modeling of flow in coaxial fans and subsonic ring inlet device on the maximum cruising mode of the turboprop engine, the full pressure recovery factor is calculated and it is established that the most influential factor that increases its full pressure recovery factor.

scholarly journals Mathematical Modelling and Operation Simulation of the Indirect Connection Scheme of the Heating Installation and of the Consumption Hot Water Preparation in an Accumulating Stage

2021 ◽  
Vol 1203 (2) ◽  
pp. 022077
Author(s):  
Danut Tokar ◽  
Sanda Mirela Toropoc ◽  
Rodica Frunzulica ◽  
Petrica Toma ◽  
Adriana Tokar
Keyword(s):  
Mathematical Model ◽  
Heat Exchanger ◽  
Hot Water ◽  
Domestic Hot Water ◽  
Indirect Connection ◽  
Model And Simulation ◽  
Module Type ◽  
Quantity Of Heat ◽  
The Mathematical Model ◽  
Residential Consumers

Abstract This paper presents the mathematical model and simulation of a thermal system for heating and supplying hot water to industrial or residential consumers consisting of a heat exchanger on the heating circuit and a heat exchanger provided with an accumulation tank on the domestic hot water circuit, this scheme is generally adopted in the industrial thermal points and increasingly in module-type thermal points for residential consumers. The mathematical model is based on the mathematical equations describing this system and developed using the MATLAB - Simulink program. Thus, as a result of the simulations, we can see the evolutions in time of the water temperatures on the heating circuit and the domestic hot water circuit, as well as the quantity of heat delivered by them.

Sign in / Sign up

Export Citation Format

Share Document