scholarly journals Experimental research and CFD analysis of flow parameters in a SCR system for the original part and WALKER’s replacement

2019 ◽  
Vol 179 (4) ◽  
pp. 13-20
Author(s):  
Damian KURZYDYM ◽  
Adam KLIMANEK ◽  
Zbigniew ŻMUDKA
Keyword(s):  
Reverse Engineering ◽  
Experimental Research ◽  
Gas Flow ◽  
Catalytic Reduction ◽  
Ansys Fluent ◽  
Flow Parameters ◽  
3D Geometry ◽  
Flow Through ◽  
Original Part ◽  
Scr System

The article presents the results of experimental research and their comparison with CFD simulations for the original selective catalytic reduction system and WALKER replacement. The research was performed to develop the WALKER universal mixer. The SCR prototype without mixer and with the proposed mixer were tested and compared with the original VW part. The next step was reverse engineering, which consisted in scanning the tested parts with a laser and processing their point cloud in Leios2 program. Reverse engineering has allowed the reconstruction of 3D geometry of the tested parts in the Catia v5 program and then preparation their models for computational fluid dynamics. Numerical simulations were carried out in the Ansys Fluent program, thanks to which several quantities were determined e.g. uniformity index of gas flow through the monolith and coefficient of variation as a measure of mixing degree, which have a significant impact on the design of the mixer and the SCR system.

scholarly journals Experimental Research of Gaseous Emissions Impact on the Performance of New-Design Cylindrical Multi-Channel Cyclone with Adjustable Half-Rings

2022 ◽  
Vol 14 (2) ◽  
pp. 902
Author(s):  
Aleksandras Chlebnikovas ◽  
Dainius Paliulis ◽  
Kristina Kilikevičienė ◽  
Artūras Kilikevičius
Keyword(s):  
Experimental Research ◽  
Gas Flow ◽  
Collection Efficiency ◽  
Fine Particulate Matter ◽  
Air Flow ◽  
Gaseous Emissions ◽  
Channel System ◽  
Flow Parameters ◽  
The Impact ◽  
Channel Type

Cyclones are widely used for separating particles from gas in energy production objects. The efficiency of conventional centrifugal air cleaning devices ranges from 85 to 90%, but the weakness of many cyclones is the low collection efficiency of particles less than 10 μm in diameter. The novelty of this work is the research of the channel-type treatment device, with few levels adapted for precipitation of fine particulate matter, acting by a centrifugal and filtration principle. Many factors have an impact on cyclone efficiency—humidity, temperature, gas (air) composition, airflow velocity and etc. Many scientists evaluated only the effect of origin and size of PM on cyclone efficiency. The effect of gas (air) composition and temperature, and humidity on the multi-channel cyclone-separator efficiency still demands contributions. Complex theoretical and experimental research on air flow parameters and the efficiency of a cylindrical eight-channel system with adjustable half-rings for removing fine-dispersive particles (<20 μm) was carried out. The impact of air humidity and temperature on air flow, and gaseous smoke components on the removal of wood ashes was analyzed. The dusty gas flow was regulated. During the experiment, the average velocity of the cyclone was 16 m/s, and the temperature was 20–50 °C. The current paper presents experimental research results of wood ash removal in an eight-channel cyclone and theoretical methodology for the calculation of airflow parameters and cyclone effectiveness.

scholarly journals Simulation and Modeling of Flow in a Gas Compressor

2015 ◽  
Vol 2015 ◽  
pp. 1-7
Author(s):  
Anna Avramenko ◽  
Alexey Frolov ◽  
Jari Hämäläinen
Keyword(s):  
Steady State ◽  
Mass Flow ◽  
Gas Flow ◽  
Simulation Method ◽  
High Mass ◽  
Ansys Fluent ◽  
Flow Rates ◽  
Mass Flow Rates ◽  
Low Mass ◽  
Flow Through

The presented research demonstrates the results of a series of numerical simulations of gas flow through a single-stage centrifugal compressor with a vaneless diffuser. Numerical results were validated with experiments consisting of eight regimes with different mass flow rates. The steady-state and unsteady simulations were done in ANSYS FLUENT 13.0 and NUMECA FINE/TURBO 8.9.1 for one-period geometry due to periodicity of the problem. First-order discretization is insufficient due to strong dissipation effects. Results obtained with second-order discretization agree with the experiments for the steady-state case in the region of high mass flow rates. In the area of low mass flow rates, nonstationary effects significantly influence the flow leading stationary model to poor prediction. Therefore, the unsteady simulations were performed in the region of low mass flow rates. Results of calculation were compared with experimental data. The numerical simulation method in this paper can be used to predict compressor performance.

scholarly journals THE EFFECT OF CONVERGENT-DIVERGENT NOZZLE PROFILE ON ITS PERFORMANCE

2019 ◽  
Vol 19 (1) ◽  
pp. 14-43
Author(s):  
Arkan Al-Taie ◽  
Hussien W Mashi ◽  
Ali M Hadi
Keyword(s):  
Mach Number ◽  
Static Pressure ◽  
Pressure Ratio ◽  
Sharp Decrease ◽  
Inlet Pressure ◽  
Ansys Fluent ◽  
Static Pressure Distribution ◽  
Flow Parameters ◽  
Sudden Rise ◽  
Flow Through

The paper presents the effect of convergent-divergent nozzles profile across specified inlet pressures values from (1.5 bar-4 bar), with constant back pressure of (1 bar). The flow of air through three convergent-divergent nozzles was studied theoretically. The flow was assumed to be one-dimensional, adiabatic and reversible (isentropic). The flow parameters like static pressure ratio and Mach number were analyzed. The flow parameters were obtained in term of area ratio along the nozzle. MATLAB code was built in order to find the Mach number along the nozzles, by using Newton-Raphson method. The shockwave position inside the nozzles was determined, using "analytic method". ANSYS fluent 18 was used to simulate the flow through the three nozzles. Two- dimensional, turbulent and viscous models were utilized to solve the governing equations. K-? model was used to model the turbulent effect. The results concluded that, reduction in inlet pressure can not affect the flow upstream the throat. Also the shockwave appearance can be noticed by a sudden rise in static pressure associated with a sharp decrease in Mach number. Shockwave moves toward the throat by reduction the inlet total pressure .By comparison the static pressure distribution along the three nozzles where can be deduced that the profile has an effect on the flow character i.e. (static pressure Mach no).The best performance among the nozzles is the performance of nozzle (N1), which (75%) of its length work as nozzle at the lowest inlet pressure of (1.5bar) while (44% and 60%) of the nozzles length for (N2 and N3) respectively work as the nozzle.

scholarly journals Analysis of the impact of the labyrinth seal geometric parameters on the leakage

2021 ◽  
Vol 323 ◽  
pp. 00015
Author(s):  
Damian Joachimiak ◽  
Piotr Krzyślak
Keyword(s):  
Experimental Research ◽  
Gas Flow ◽  
Labyrinth Seal ◽  
Gas Pressure ◽  
Geometric Parameters ◽  
Labyrinth Seals ◽  
Flow Parameters ◽  
Number Of Teeth ◽  
The Impact ◽  
Size Data

This paper includes results of experimental research and CFD calculations concerning gas flow in segments of straight through labyrinth seals of fixed length and varying number of teeth. Relation between the number of teeth and the leakage is analyzed in this paper. Authors determined the range of teeth number for which the minimum leakage was achieved. They focused particularly on the analysis of geometry with maximum number of teeth which fell within the range of the minimum leakage. For this geometry they examined the relation between the thickness of the teeth and the distribution of gas pressure and velocity along the seal and the leakage size. Data presented in this paper indicate that the teeth thickness has a significant impact on the flow parameters.

scholarly journals Experimental Research and CFD Calculations Based Investigations Into Gas Flow in a Short Segment of a Heavily Worn Straight Through Labyrinth Seal

2017 ◽  
Vol 24 (2) ◽  
pp. 83-88 ◽  
Author(s):  
Damian Joachimiak ◽  
Piotr Krzyślak
Keyword(s):  
Experimental Research ◽  
Power Plants ◽  
Gas Flow ◽  
Labyrinth Seal ◽  
Steam Turbines ◽  
Static Pressure Distribution ◽  
Flow Parameters ◽  
Working Medium ◽  
Theoretical Assumptions ◽  
Flow Phenomena

Abstract Steam turbines are used as propulsion components in not only power plants but also on merchant and naval ships. The geometry of the steam turbine seals changes throughout the machine life cycle. The rate of deterioration of these seals, in turn, affects heavily the efficiency of the thermal machine. However, the literature overview does not provide any research reports on flow phenomena occurring in heavily deteriorated seals. The paper describes the course and results of investigations into a model straight through labyrinth seal composed of 4 discs, each with the slot height of 2 mm. The investigations have been conducted with air as the working medium. Changes of gas flow parameters due to wear were analysed. Based on the experimental data, more intensive leakage was observed as the result of the increased slot height. The static pressure distribution along the examined segment was measured. The experimentally recorded distribution differed remarkably from the theoretical assumptions. Another part of the experimental research focused on comparing the gas velocities at points situated upstream of the first and second seal disc. The velocity measurements were carried out using a constant temperature wire probe. This part of the investigations provided opportunities for analysing the influence of seal wear on gas flow conditions in the seal segment. The paper compares the results of the experimental research with those obtained using the CFX software. The presented results of velocity distributions provide a clear picture of the nature of the gas flow in the seal, which enables its analysis.

scholarly journals Spraying and Mixing Characteristics of Urea in a Static Mixer Applied Marine SCR System

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5788
Author(s):  
Jaehwan Jang ◽  
Sangkyung Na ◽  
Heehwan Roh ◽  
Seongyool Ahn ◽  
Gyungmin Choi
Keyword(s):  
Degrees Of Freedom ◽  
Gas Flow ◽  
Catalytic Reduction ◽  
Water Solution ◽  
Urea Solution ◽  
Static Mixer ◽  
Manufacturing Companies ◽  
Conversion Reaction ◽  
Marine Diesel ◽  
Scr System

The most effective de-NOx technology in marine diesel applications is the urea-based selective catalytic reduction (SCR) system. The urea-SCR system works by injecting a urea solution into exhaust gas and converting this to NH3 and CO2. The injection, mixing, and NH3 conversion reaction behavior of the urea-water solution all have a decisive effect on the performance of the system. To improve de-NOx efficiency, it is important to provide enough time and distance for NH3 conversion and uniform distribution prior to the solution entering the catalyst. In this study, therefore, the characteristics of gas flow, NH3 conversion, and its distribution are investigated with a static mixer by means of numerical methods, providing a special advantage to ship manufacturing companies through the optimization of the urea-SCR system. The results show that the inclusion of the mixer induces strong turbulence and promotes the NH3 conversion reaction across a wider region compared to the case without the mixer. The mean temperature is 10 °C lower due to the activated endothermic urea-NH3 conversion reaction and the NH3 concentration is 80 PPM higher at 1D than those without the mixer. Moreover, the uniformity of NH3 distribution improved by 25% with the mixer, meaning that the de-NOx reaction can take place across all aspects of the catalyst thus maximizing performance. In other words, ship manufacturing companies have degrees of freedom in designing post-processing solutions for emissions by minimizing the use of the reduction agent or the size of the SCR system.

Leveraging Physical and Computational Flow Modeling Techniques in the Optimization of Commercial Selective Catalytic Reduction System Designs

2002 ◽  
Author(s):  
David K. Anderson ◽  
Martin J. Kozlak
Keyword(s):  
Gas Flow ◽  
Catalytic Reduction ◽  
Flow Characteristics ◽  
Flow Models ◽  
Low Load ◽  
Modeling Techniques ◽  
Fluid Flow Characteristics ◽  
Scr System ◽  
System Designs ◽  
Ammonia Injection

To ensure optimal SCR system performance, physical and computational flow models of proposed SCR installations are used to guide the development of system components, such as the ammonia injection grid and various flow and thermal conditioning devices. Proper attention to these details is particularly important in retrofit applications where the ducts leading to the SCR reactor often cannot be designed for optimal fluid flow characteristics. This paper discusses the process of SCR modeling including the techniques employed to accurately model gas flow, NOx, ammonia, and thermal distributions and mixing. Additionally, the development of economizer bypass systems for SCR temperature control during low-load operation is discussed.

scholarly journals Development of the model for a diesel engine catalytic converter

2019 ◽  
Vol 140 ◽  
pp. 06013
Author(s):  
Artem Blinov ◽  
Nikolay Malastowski ◽  
Leonid Myagkov
Keyword(s):  
Gas Flow ◽  
Catalytic Reduction ◽  
Catalytic Converter ◽  
Nox Reduction ◽  
Scr Catalyst ◽  
Flow Parameters ◽  
Key Issues ◽  
Automatic Mesh ◽  
Engine Development ◽  
Cross Section Geometry

One of the key issues of the modern engine development is to comply with today’s stringent emission standards. It forces the manufacturers to enhance in-engine and after treatment emission reduction technologies continuously. The selective catalytic reduction (SCR) is still the most effective technique for nitrogen oxides removal from exhaust gases of vehicles with diesel engines. Numerical modelling is widely used for SCR systems development and assessment. In this paper, a simplified one-dimensional numerical model of diesel SCR catalyst, which was implemented in Matlab, is described. The algorithm for automatic mesh generation describing real cross-section geometry of the catalyst block and the calculation procedure allowing to take into account non-uniform distribution of the gas flow parameters at the catalyst inlet are presented. Model was validated by the experimental data available in the literature. Numerical simulations for the full-scale modern SCR catalyst were carried out. The effect of the gas velocity non-uniformity at the catalyst inlet on the overall NOx reduction efficiency was evaluated.

scholarly journals Modeling the working media flow in shut-off valves with displacement of the regulating body perpendicular to the flow axis

2021 ◽  
Vol 2057 (1) ◽  
pp. 012017
Author(s):  
V V Soloveva ◽  
A S Pugachuk ◽  
A V Chernyschev
Keyword(s):  
Fluid Flow ◽  
Gas Flow ◽  
Reynolds Numbers ◽  
Working Fluid ◽  
Flow Section ◽  
Flow Parameters ◽  
Wide Range ◽  
Flow Part ◽  
Flow Through ◽  
Working Media

Abstract The mathematical model of the working fluid movement in the flow section of the wedge type two-disc parallel gate valve is developed. The simulation of the fluid flow through the valve cavity is carried out, as a result the flow parameters are obtained in a wide range of Reynolds numbers at the entrance to the calculated area. The dependence of the hydraulic resistance as a function of the Reynolds number for liquid and gas flow is calculated. The various positions of the shut-off body in the flow part of the valve are considered and the area of reduced pressures in which the effect of cavitation may occur during fluid flow is estimated.

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