Design of a Quench Device for Synthesis and Hydrolysis of Zn Nanoparticles: Flow Modeling and Experiments

2008 ◽  
Author(s):  
Aiman Alshare ◽  
Tareq Abu Hamed ◽  
Marc Bru¨lhart ◽  
Luke Venstrom ◽  
Jane H. Davidson
Keyword(s):  
Particle Deposition ◽  
Fluid Dynamic ◽  
Tubular Reactor ◽  
Numerical Data ◽  
Confined Jets ◽  
Zinc Nanoparticles ◽  
Modeling And Experiments ◽  
The Impact ◽  
Hydrolysis Of ◽  
Reactor Surface

The synthesis and hydrolysis of zinc nanoparticles are carried out in a tubular reactor. A key component of the reactor is a coaxial jet quench device. Three co-axial and multi-inlet confined jets mix Zn(g), steam and argon to produce and hydrolyze zinc nanoparticles. The performance of the quench device is assessed with computational fluid dynamic modeling and measurements of hydrogen conversion and particle size and composition. Numerical data elucidate the impact of varying jet flow rates on temperature and velocity distributions within the reactor. Experiments produce hydrogen conversions of 61 to 79%. Particle deposition on sections of the reactor surface above 650 K favors hydrolysis. Residence time for in-flight particles is less than one second and these particles are partially hydrolyzed.

Study of a Quench Device for the Synthesis and Hydrolysis of Zn Nanoparticles: Modeling and Experiments

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Tareq Abu Hamed ◽  
Luke Venstrom ◽  
Aiman Alshare ◽  
Marc Brülhart ◽  
Jane H. Davidson
Keyword(s):  
Particle Deposition ◽  
Tubular Reactor ◽  
Numerical Data ◽  
Dynamics Modeling ◽  
Computational Fluid Dynamics Modeling ◽  
Confined Jets ◽  
Zinc Nanoparticles ◽  
Modeling And Experiments ◽  
The Impact ◽  
Hydrolysis Of

The synthesis and hydrolysis of zinc nanoparticles are carried out in a tubular reactor. A key component of the reactor is a coaxial jet quench device. Three coaxial and multi-inlet confined jets mix Zn(g), steam, and argon to produce and hydrolyze zinc nanoparticles. The performance of the quench device is assessed with computational fluid dynamics modeling and measurements of hydrogen conversion and particle size and composition. Numerical data elucidate the impact of varying jet flow rates on temperature and velocity distributions within the reactor. Experiments produce hydrogen conversions of 61–79%. Particle deposition on sections of the reactor surface above 650 K favors hydrolysis. Residence time for in-flight particles is less than 1 s and these particles are partially hydrolyzed.

Quantitative Computational Fluid Dynamics Analyses of Particle Deposition on a Transonic Axial Compressor Blade—Part I: Particle Zones Impact

2014 ◽  
Vol 137 (2) ◽  
Author(s):  
Alessio Suman ◽  
Rainer Kurz ◽  
Nicola Aldi ◽  
Mirko Morini ◽  
Klaus Brun ◽  
...  
Keyword(s):  
Gas Turbines ◽  
Particle Deposition ◽  
Fluid Dynamic ◽  
Axial Compressor ◽  
Numerical Data ◽  
Suction Side ◽  
Continuous Phase ◽  
Industrial Applications ◽  
Compressor Rotor ◽  
The Impact

Solid particle ingestion is one of the principal degradation mechanisms in the turbine and compressor sections of gas turbines. In particular, in industrial applications, the microparticles that are not captured by the air filtration system cause fouling and, consequently, a performance drop of the compressor. This paper presents three-dimensional numerical simulations of the microparticle ingestion (0 μm–2 μm) on an axial compressor rotor carried out by means of a commercial computational fluid dynamic (CFD) code. Particles of this size can follow the main air flow with relatively little slip, while being impacted by flow turbulence. It is of great interest to the industry to determine which areas of the compressor airfoils are impacted by these small particles. Particle trajectory simulations use a stochastic Lagrangian tracking method that solves the equations of motion separate from the continuous phase. Then, the NASA Rotor 37 is considered as a case study for the numerical investigation. The compressor rotor numerical model and the discrete phase treatment have been validated against the experimental and numerical data available in literature. The number of particles, sizes, and concentrations are specified in order to perform a quantitative analysis of the particle impact on the blade surface. The results show that microparticles tend to follow the flow by impacting at full span with a higher impact concentration on the pressure side (PS). The suction side (SS) is affected only by the impact of the smaller particles (up to 1 μm). Particular fluid dynamic phenomena, such as separation, stagnation point, and tip leakage vortex, strongly influence the impact location of the particles.

Fouling on a Multistage Axial Compressor in the Presence of a Third Substance at the Particle/Surface Interface

2018 ◽  
Author(s):  
Nicola Aldi ◽  
Nicola Casari ◽  
Devid Dainese ◽  
Mirko Morini ◽  
Michele Pinelli ◽  
...  
Keyword(s):  
Impact Velocity ◽  
Gas Turbines ◽  
Particle Deposition ◽  
Fluid Dynamic ◽  
Particle Surface ◽  
Axial Compressor ◽  
Micro Particles ◽  
Multistage Compressor ◽  
Particle Ingestion ◽  
The Impact

Solid particle ingestion is one of the principal degradation mechanisms in the compressor and turbine sections of gas turbines. In particular, in industrial applications, the micro-particles not captured by the air filtration system can cause deposits on blades and, consequently, can result in a decrease in compressor performance. It is of great interest to the industry to determine which zones of the compressor blades are impacted by these small particles. However, this information often refers to single stage analysis. This paper presents three-dimensional numerical simulations of the micro-particle ingestion (0.15 μm – 1.50 μm) in a multistage (i.e. eight stage) subsonic axial compressor, carried out by means of a commercial CFD code. Particle trajectory simulations use a stochastic Lagrangian tracking method that solves the equations of motion separately from the continuous phase. The effects of humidity, or more generally, the effects of a third substance at the particle/surface interface (which is considered one of the major promoters of fouling) is then studied. The behavior of wet and oiled particles, in addition to the usual dry particles, is taken into consideration. In the dry case, the particle deposition is established only by using the sticking probability. This quantity links the kinematic characteristics of particle impact on the blade with the fouling phenomenon. In the other two cases, the effect of the presence of a third substance at the particle/surface interface is considered by means of an energy-based model. Moreover, the influence of the tangential impact velocity on particle deposition is analyzed. Introducing the effect of a third substance, such as humidity or oil, the phenomenon of fouling concerns the same areas of the multistage compressor. The most significant results are obtained by combining the effect of the third substance with the effect of the tangential component of the impact velocity of the particles. The deposition trends obtained with these conditions are comparable with those reported in literature, highlighting how the deposits are mainly concentrated in the early stages of a multistage compressor. Particular fluid dynamic phenomena, such as corner separations and clearance vortices, strongly influence the location of particle deposits.

Quantitative CFD Analyses of Particle Deposition on a Transonic Axial Compressor Blade: Part I — Particle Zones Impact

2014 ◽  
Author(s):  
Alessio Suman ◽  
Rainer Kurz ◽  
Nicola Aldi ◽  
Mirko Morini ◽  
Klaus Brun ◽  
...  
Keyword(s):  
Gas Turbines ◽  
Particle Deposition ◽  
Fluid Dynamic ◽  
Axial Compressor ◽  
Continuous Phase ◽  
Industrial Applications ◽  
Micro Particles ◽  
Compressor Rotor ◽  
Particle Ingestion ◽  
The Impact

Solid particle ingestion is one of the principal degradation mechanisms in the turbine and compressor sections of gas turbines. In particular, in industrial applications, the micro-particles not captured by the air filtration system cause fouling and, consequently, a performance drop of the compressor. This paper presents three-dimensional numerical simulations of the micro-particle ingestion (0–2 μm) on an axial compressor rotor carried out by means of a commercial computational fluid dynamic code. Particles of this size can follow the main air flow with relatively little slip, while being impacted by flow turbulence. It is of great interest to the industry to determine which areas of the compressor airfoils are impacted by these small particles. Particle trajectory simulations use a stochastic Lagrangian tracking method that solves the equations of motion separate from the continuous phase. Then, the NASA Rotor 37 is considered as a case study for the numerical investigation. The compressor rotor numerical model and the discrete phase treatment have been validated against the experimental and numerical data available in literature. The number of particles, sizes, and concentrations are specified in order to perform a quantitative analysis of the particle impact on the blade surface. The results show that micro-particles tend to follow the flow by impacting at full span with an higher impact concentration on the pressure side. The suction side is affected only by the impact of the smaller particles (up to 1 μm). Particular fluid-dynamic phenomena such as separation, stagnation point and tip leakage vortex strongly influence the impact location of the particles.

Quantitative CFD Analyses of Particle Deposition on a Subsonic Axial Compressor Blade

2015 ◽  
Author(s):  
Alessio Suman ◽  
Rainer Kurz ◽  
Nicola Aldi ◽  
Mirko Morini ◽  
Klaus Brun ◽  
...  
Keyword(s):  
Particle Deposition ◽  
Fluid Dynamic ◽  
Axial Compressor ◽  
Leading Edge ◽  
Suction Side ◽  
Sticking Probability ◽  
Particle Impact ◽  
Kinematic Characteristics ◽  
The Impact ◽  
Dynamic Phenomena

In literature there are some studies related to the fouling phenomena in transonic compressors, but, in industrial applications (heavy-duty compressor, pump stations, etc.) the subsonic compressors are widespread. It is of great interest to the manufacturer to discover the fouling phenomenon related to this type of compressor. This paper presents three-dimensional numerical simulations of the micro-particle ingestion on a subsonic axial compressor rotor carried out by means of a commercial computational fluid dynamic code. Particle trajectory simulations use a stochastic Lagrangian tracking method that solves the equations of motion separate from the continuous phase. The number of particles, sizes, and concentrations are specified in order to perform a quantitative analysis of the particle impact on the blade surface. In this paper the particle impact pattern and the kinematic characteristics (velocity and angle) of the impact are shown. Both of the blade zones affected by particle impact and the blade zones affected by particle deposition are analyzed. The particle deposition is established by using the quantity called sticking probability. The sticking probability links the kinematic characteristics of particle impact on the blade with fouling phenomenon. The results show that micro-particles tend to follow the flow by impacting at full span with a higher impact concentration on the leading edge. The suction side is affected only close to the leading edge and, at the hub, close to the trailing edge. Particular fluid-dynamic phenomena such as separation, stagnation and tip leakage vortex strongly influence the impact location of the particles. The kinematic analysis showed a high tendency of particle adhesion on the suction side, especially for smaller particles for which the fluid dynamic phenomena play a key role regarding particle impact velocity and angle.

Estimation of the Particle Deposition on a Subsonic Axial Compressor Blade

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Alessio Suman ◽  
Mirko Morini ◽  
Rainer Kurz ◽  
Nicola Aldi ◽  
Klaus Brun ◽  
...  
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
Particle Deposition ◽  
Fluid Dynamic ◽  
Axial Compressor ◽  
Interdisciplinary Approach ◽  
Blade Surface ◽  
Air Filtration ◽  
Filtration System ◽  
The Impact

The quality and purity of the air entering a gas turbine is a significant factor influencing its performance and life. Foulants in the ppm range which are not captured by the air filtration system usually cause deposits on blading, which results in a severe drop in the performance of the compressor. Through the interdisciplinary approach proposed in this paper, it is possible to determine the evolution of the fouling phenomenon through the integration of studies in different research fields: (i) numerical simulation, (ii) power plant characteristics, and (iii) particle-adhesion characteristics. In fact, the size of the particles, their concentrations and adhesion ability, and filtration efficiency represent the major contributors for performing a realistic quantitative analysis of fouling phenomena in an axial compressor. The aim of this work is the estimation of actual deposits on the blade surface in terms of location and quantity. This study combines the impact/adhesion characteristic of the particles obtained through a computational fluid dynamic (CFD) and the real size distribution of the contaminants in the air swallowed by the compressor. The blade zones affected by deposits are clearly reported by using easy-to-use contaminant maps realized on the blade surface, in terms of contaminant mass. The analysis has shown that particular fluid-dynamic phenomena and airfoil shape influence the pattern deposition. The use of a filtration system decreases the contamination of blade and the charge level of electrostatic filters seems to be less important than the air contaminant concentration. From these analyses, some guidelines for proper installation and management of the power plant (in terms of filtration systems and washing strategies) can be drawn up. Characterization of the air contaminants in the power plant location represents the most important step in improving the management of the gas turbine power plant.

Quantitative Computational Fluid Dynamics Analyses of Particle Deposition in a Heavy-Duty Subsonic Axial Compressor

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Nicola Aldi ◽  
Nicola Casari ◽  
Devid Dainese ◽  
Mirko Morini ◽  
Michele Pinelli ◽  
...  
Keyword(s):  
Particle Deposition ◽  
Fluid Dynamic ◽  
Axial Compressor ◽  
Industrial Applications ◽  
Particle Impact ◽  
Blade Surface ◽  
Heavy Duty ◽  
Compressor Blades ◽  
Kinematic Characteristics ◽  
The Impact

Solid particle ingestion is one of the principal degradation mechanisms in the compressor and turbine sections of gas turbines. In particular, in industrial applications, the microparticles not captured by the air filtration system can cause deposits on blading and, consequently, result in a decrease in compressor performance. In the literature, there are some studies related to the fouling phenomena in transonic compressors, but in industrial applications (heavy-duty compressors, pump stations, etc.), the subsonic compressors are widespread. It is highly important for the manufacturer to gather information about the fouling phenomenon related to this type of compressor. This paper presents three-dimensional (3D) numerical simulations of the microparticle ingestion (0.15–1.50 μm) in a multistage (i.e., eight stage) subsonic axial compressor, carried out by means of a commercial computational fluid dynamic (CFD) code. Particles of this size can follow the main air flow with relatively little slip, while being impacted by flow turbulence. It is of great interest to the industry to determine which zones of the compressor blades are impacted by these small particles. Particle trajectory simulations use a stochastic Lagrangian tracking method that solves the equations of motion separately from the continuous phase. The adopted computational strategy allows the evaluation of particle deposition in a multistage axial compressor thanks to the use of a mixing plane approach to model the rotor/stator interaction. The compressor numerical model and the discrete phase model are set up and validated against the experimental and numerical data available in the literature. The number of particles and sizes is specified in order to perform a quantitative analysis of the particle impacts on the blade surface. The blade zones affected by particle impacts and the kinematic characteristics (velocity and angle) of the impact of micrometric and submicrometric particles with the blade surface are shown. Both blade zones affected by particle impact and deposition are analyzed. The particle deposition is established by using the quantity called sticking probability (SP), adopted from the literature. The SP links the kinematic characteristics of particle impact on the blade with the fouling phenomenon. The results show that microparticles tend to follow the flow by impacting on the compressor blades at full span. The suction side (SS) of the blade is only affected by the impacts of the smallest particles. Particular fluid dynamic phenomena, such as corner separations and clearance vortices, strongly influence the impact location of the particles. The impact and deposition trends decrease according to the stages. The front stages appear more affected by particle impact and deposition than the rear ones.

Estimation of the Particle Deposition on a Subsonic Axial Compressor Blade

2016 ◽  
Author(s):  
Alessio Suman ◽  
Mirko Morini ◽  
Rainer Kurz ◽  
Nicola Aldi ◽  
Klaus Brun ◽  
...  
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
Particle Deposition ◽  
Fluid Dynamic ◽  
Axial Compressor ◽  
Interdisciplinary Approach ◽  
Blade Surface ◽  
Air Filtration ◽  
Filtration System ◽  
The Impact

The quality and purity of the air entering a gas turbine is a significant factor influencing its performance and life. Foulants in the ppm range which are not captured by the air filtration system usually cause deposits on blading, which results in a severe drop in the performance of the compressor. Through the interdisciplinary approach proposed in this paper, it is possible to determine the evolution of the fouling phenomenon through the integration of studies in different research fields: (i) numerical simulation, (ii) power plant characteristics and (iii) particle-adhesion characteristics. In fact, the size of the particles, their concentrations and adhesion ability, and filtration efficiency represent the major contributors to performing a realistic quantitative analysis of fouling phenomena in an axial compressor. The aim of this work is the estimation of the actual deposits on the blade surface in terms of location and quantity. This study combines the impact/adhesion characteristic of the particles obtained through a CFD and the real size distribution of the contaminants in the air swallowed by the compressor. The blade zones affected by deposits are clearly reported by using easy-to-use contaminant maps realized on the blade surface, in terms of contaminant mass. The analysis has shown that particular fluid-dynamic phenomena and airfoil shape influence the pattern deposition. The use of a filtration system decreases the contamination of the blade and the charge level of the electrostatic seems to be less important than the air contaminant concentration. From these analyses, some guidelines for proper installation and management of the power plant (in terms of filtration systems and washing strategies) can be drawn up. Characterization of the air contaminants in the power plant location represents the most important step in improving the management of the gas turbine power plant.

An Innovative Method for the Evaluation of Particle Deposition Accounting for the Rotor/Stator Interaction

2016 ◽  
Author(s):  
Nicola Aldi ◽  
Mirko Morini ◽  
Michele Pinelli ◽  
Pier Ruggero Spina ◽  
Alessio Suman
Keyword(s):  
Rotor Blade ◽  
Particle Deposition ◽  
Fluid Dynamic ◽  
Axial Compressor ◽  
Suction Side ◽  
Particle Impact ◽  
Compressor Stage ◽  
Micro Particles ◽  
Particle Ingestion ◽  
The Impact

Solid particle ingestion is one of the principal degradation mechanisms in the compressor and turbine sections of gas turbines. In particular, in industrial applications, the micro-particles not captured by the air filtration system can cause deposits on blading and, consequently, result in a performance drop of the compressor. This paper presents three-dimensional numerical simulations of the micro-particle ingestion (0.15 μm – 1.50 μm) in a transonic axial compressor stage, carried out by means of a commercial computational fluid dynamic code. Particles of this size can follow the main air flow with relatively little slip, while being impacted by flow turbulence. It is of great interest to the industry to determine which zones of the compressor blades are impacted by these small particles. Particle trajectory simulations use a stochastic Lagrangian tracking method that solves the equations of motion separately from the continuous phase. A particular computational strategy is adopted in order to take into account the presence of two subsequent annular cascades (rotor and stator) in the case of particle ingestion. The proposed strategy allows the evaluation of particle deposition in an axial compressor stage thanks to its capability of accounting for the rotor/stator interaction. NASA Stage 37 is considered as a case study for the numerical investigation. The compressor stage numerical model and the discrete phase model are set up and validated against the experimental and numerical data available in literature. The blade zones affected by particle impact and the kinematic characteristics of the impact of micrometric and sub-micrometric particles with the blade surface are shown. Both blade zones interested by particle impact and deposition are analyzed. The particle deposition is established by using the quantity called sticking probability, adopted from literature. The sticking probability links the kinematic characteristics of particle impact on the blade with fouling phenomenon. The results show that micro-particles tend to follow the flow by impacting at full span with a higher impact concentration on the pressure side of rotor blade and stator vane. Both rotor blade and stator vane suction side are affected only by the impact of smaller particles (up to 1 μm). Particular fluid dynamic phenomena, such as separation, shock waves and tip leakage vortex, strongly influence the impact location of the particles. The kinematic analysis shows a high tendency of particle adhesion on the suction side of the rotor blade, especially for particles with a diameter equal to 0.15 μm.

Quantitative CFD Analyses of Particle Deposition on a Transonic Axial Compressor Blade: Part II — Impact Kinematics and Particle Sticking Analysis

2014 ◽  
Author(s):  
Alessio Suman ◽  
Mirko Morini ◽  
Rainer Kurz ◽  
Nicola Aldi ◽  
Klaus Brun ◽  
...  
Keyword(s):  
Gas Turbines ◽  
Particle Deposition ◽  
Fluid Dynamic ◽  
Axial Compressor ◽  
Particle Impact ◽  
High Tendency ◽  
Compressor Rotor ◽  
Kinematic Characteristics ◽  
Starting Point ◽  
The Impact

In heavy-duty gas turbines, the micro-particles not captured by the air filtration system can cause fouling and, consequently, a performance drop of the compressor. This paper presents three-dimensional numerical simulations of the micro-particle ingestion (0–2 μm) on an axial compressor rotor carried out by means of a commercial computational fluid dynamic code. Particle trajectory simulations use a stochastic Lagrangian tracking method that solves the equations of motion separately from the continuous phase. The NASA Rotor 37 is considered as a case study for the numerical investigation. The compressor rotor numerical model and the discrete phase model were previously validated by the authors in the first part of this work. The kinematic characteristics (velocity and angle) of the impact of micrometric and sub-micrometric particles with the blade surface of an axial transonic compressor are shown. The blade zones affected by particle impact were extensively analyzed and reported in the first part of this work, forming the starting point for the analyses shown in this paper. The kinematic analysis showed a high tendency of particle adhesion on the suction side, especially for the particles with a diameter equal to 0.25 μm. Fluid dynamic phenomena and airfoil shape play a key role regarding particle impact velocity and angle. This work has the goal of combining, for the first time, the kinematic characteristics of particle impact on the blade with fouling phenomenon by the use of a quantity called sticking probability adopted from literature. From these analyses, some guidelines for a proper management of the power plant (in terms of filtration and washing strategies) are highlighted.

Sign in / Sign up

Export Citation Format

Share Document