Optimization of an Effervescent Atomizer to the Combustion of Residue Oils

Author(s):  
Manuel E. C. Ferreira ◽  
Jorge J. G. Martins ◽  
Jose´ C. F. Teixeira

This paper reports the geometrical optimization of an effervescent atomizer used in the combustion of used recycled oils. The objective was to obtain stable flames while minimizing the emission levels. A test facility was designed and constructed, which included: a furnace rated at a thermal input of 300 kW and a swirl generator as a part of the burner setup for the application of the effervescent atomizer. Other auxiliary facilities were also included, such as: cooling system, air supplies and pre-heating gas burner. Combustion tests were carried out with used recycled oil having a viscosity of 46 mm2/s (50°C) and a higher heating value of 44.6 MJ/kg. Results included qualitative observations of the ignition and flame stabilization, emission concentrations and LDA velocity measurements of the flow field produced by the swirl generator with and without flame. The results show a good performance of the swirl generator in the process of fuel/air mixing inside the furnace, which results in very low emission levels. The various tests carried out with different geometric configurations of the burning facility clearly suggest that the high velocity and penetration of the spray require an adequate design of the swirl generator and the nozzle orifice, in order to obtain a good air/fuel mixture inside the furnace.


Author(s):  
Boris F. Kock ◽  
Bernd Prade ◽  
Benjamin Witzel ◽  
Holger Streb ◽  
Mike H. Koenig

The first Siemens AG SGT5-4000F engine with hybrid burner ring combustor (HBR) was introduced in 1996. Since then, frequent evolutionary design improvements of the combustion system were introduced to fulfill the continuously changing market requirements. The improvements particularly focused on increased thermodynamic performance, reduced emissions, and increasing operational flexibility in terms of load gradients, fuel flexibility, and turndown capability. According to the Siemens product development process, every design evolution had to pass several validation steps to ensure high reliability and best performance. The single steps included cold flow and mixing tests at atmospheric pressure, high-pressure combustion tests in full-scale sector combustion test rigs, and full engine tests at the Berlin test facility (BTF). After successful validation, the design improvements were gradually released for commercial operation. In a first step, cooling air reduction features have been implemented in 2005, followed by the introduction of a premixed pilot as second step in 2006. Both together resulted in a significant reduction of the NOx emissions of the system. In a third step, an aerodynamic burner modification was introduced in 2007, which improved the thermo-acoustic stability of the system towards higher turbine inlet temperatures and adapted to fuel preheating to allow for increased cycle efficiency. All three features together have been released as package in 2010 and to date accumulated more than 50,000 operating hours (fleet leader 24,000). This paper reports upon the steps towards this latest design status of the SGT5-4000F and presents results from typical focus areas of lean premixed combustion systems in gas turbines including aero-dynamical optimization, fuel/air mixing improvements and cooling air management in the combustor.



2021 ◽  
Author(s):  
S. J. van der Spuy ◽  
D. N. J. Els ◽  
L. Tieghi ◽  
G. Delibra ◽  
A. Corsini ◽  
...  

Abstract The MinWaterCSP project was defined with the aim of reducing the cooling system water consumption and auxiliary power consumption of concentrating solar power (CSP) plants. A full-scale, 24 ft (7.315 m) diameter model of the M-fan was subsequently installed in the Min WaterCSP cooling system test facility, located at Stellenbosch University. The test facility was equipped with an in-line torque arm and speed transducer to measure the power transferred to the fan rotor, as well as a set of rotating vane anemometers upstream of the fan rotor to measure the air volume flow rate passing through the fan. The measured results were compared to those obtained on the 1.542 m diameter ISO 5801 test facility using the fan scaling laws. The comparison showed that the fan power values correlated within +/− 7% to those of the small-scale fan, but at a 1° higher blade setting angle for the full-scale fan. To correlate the expected fan static pressure rise, a CFD analysis of the 24 ft (7.315 m) diameter fan installation was performed. The predicted fan static pressure rise values from the CFD analysis were compared to those measured on the 1.542 m ISO test facility, for the same fan. The simulation made use of an actuator disc model to represent the effect of the fan. The results showed that the predicted results for fan static pressure rise of the installed 24 ft (7.315 m) diameter fan correlated closely (smaller than 1% difference) to those of the 1.542 m diameter fan at its design flowrate but, once again, at approximately 1° higher blade setting angle.



Author(s):  
Li-Yong Han ◽  
Lin Yang ◽  
Shan Zhou ◽  
Shen Wang ◽  
Chun-Lai Tian ◽  
...  

The passive containment cooling system (PCCS) of the 3rd generation APWR utilizes natural phenomena to transfer the heat released from the reactor to the environment during postulated designed basic accidents. Steam condensation on the inner surface of the containment shell is one of the most dominate mechanism to keep the ambient conditions within the design limits. Extensive experiment and theoretical research shows condensation is a complex process, gas pressure, film temperature and velocity of the gas have impact on the heat transfer coefficient. To span the expected range of conditions and provide proper model for evaluating the condensation heat transfer process, SCOPE test facility was designed by State Nuclear Power Technology Research & Development Centre (SNPTRD) in various conditions anticipated the operating range of CAP1400 in accident conditions. Pressurized test section with a rectangular flowing channel was used, with one of the walls cooled to maintain low temperature for condensing, supplying systems was designed for different pressures, gas temperatures, velocities and coolant water temperatures. Facility components, test section structure, supplying systems and measurement technology were described in this paper, also results of some pre-tests was introduce to show property of the facility.



2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Hyun-Sik Park ◽  
Byung-Yeon Min ◽  
Youn-Gyu Jung ◽  
Yong-Cheol Shin ◽  
Yung-Joo Ko ◽  
...  

To validate the performance and safety of an integral type reactor of SMART, a thermal-hydraulic integral effect test facility, VISTA-ITL, is introduced with a discussion of its scientific design characteristics. The VISTA-ITL was used extensively to assess the safety and performance of the SMART design, especially for its passive safety system such as a passive residual heat removal system, and to validate various thermal-hydraulic analysis codes. The VISTA-ITL program includes several tests on the SBLOCA, CLOF, and PRHRS performances to support a verification of the SMART design and contribute to the SMART design licensing by providing proper test data for validating the system analysis codes. A typical scenario of SBLOCA was analyzed using the MARS-KS code to assess the thermal-hydraulic similarity between the SMART design and the VISTA-ITL facility, and a posttest simulation on a SBLOCA test for the shutdown cooling system line break has been performed with the MARS-KS code to assess its simulation capability for the SBLOCA scenario of the SMART design. The SBLOCA scenario in the SMART design was well reproduced using the VISTA-ITL facility, and the measured thermal-hydraulic data were properly simulated with the MARS-KS code.



Author(s):  
Manabu Yagi ◽  
Hidefumi Araki ◽  
Hisato Tagawa ◽  
Tomomi Koganezawa ◽  
Chihiro Myoren ◽  
...  

A 40 MW-class test facility has been constructed to verify practicability of applying the advanced humid air turbine (AHAT) system to a heavy-duty gas turbine. Verification tests have been carried out from January 2012, and interaction effects between the key components were established. First, water atomization cooling (WAC) was confirmed to contribute to both increased mass flow rate and pressure ratio for the axial-flow compressor. The good agreement between measured and calculated temperatures at the compressor discharge was also confirmed. These results demonstrated the accuracy of the developed prediction model for the WAC. Second, a control method that realized both flame stability and low nitrogen oxides (NOx) emissions was verified. Although the power output and air humidity were lower than the rated values, NOx concentration was about 10 ppm. Finally, a hybrid nozzle cooling system, which utilized both compressor discharged air and humid air, was developed and tested. The metal surface temperatures of the first stage nozzles were measured, and they were kept under the permissible metal temperature. The measured temperatures on the metal surface reasonably corresponded with calculation results.



Author(s):  
Festus Eghe Agbonzikilo ◽  
Ieuan Owen ◽  
Jill Stewart ◽  
Suresh Kumar Sadasivuni ◽  
Mike Riley ◽  
...  

This paper presents the results of an investigation in which the fuel/air mixing process in a single slot within the radial swirler of a dry low emission (DLE) combustion system is explored using air/air mixing. Experimental studies have been carried out on an atmospheric test facility in which the test domain is a large-scale representation of a swirler slot from a Siemens proprietary DLE combustion system. Hot air with a temperature of 300 °C is supplied to the slot, while the injected fuel gas is simulated using air jets with temperatures of about 25 °C. Temperature has been used as a scalar to measure the mixing of the jets with the cross-flow. The mixture temperatures were measured using thermocouples while Pitot probes were used to obtain local velocity measurements. The experimental data have been used to validate a computational fluid dynamics (CFD) mixing model. Numerical simulations were carried out using CFD software ansys-cfx. Due to the complex three-dimensional flow structure inside the swirler slot, different Reynolds-averaged Navier–Stokes (RANS) turbulence models were tested. The shear stress transport (SST) turbulence model was observed to give best agreement with the experimental data. The momentum flux ratio between the main air flow and the injected fuel jet, and the aerodynamics inside the slot were both identified by this study as major factors in determining the mixing characteristics. It has been shown that mixing in the swirler can be significantly improved by exploiting the aerodynamic characteristics of the flow inside the slot. The validated CFD model provides a tool which will be used in future studies to explore fuel/air mixing at engine conditions.



Author(s):  
Simon Gövert ◽  
Federica Ferraro ◽  
Alexander Krumme ◽  
Clemens Buske ◽  
Marc Tegeler ◽  
...  

Abstract Reducing the uncertainties in the prediction of turbine inlet conditions is a crucial aspect to improve aero engine designs and further increase engine efficiencies. To meet constantly stricter emission regulations, lean burn combustion could play a key role for future engine designs. However, these combustion systems are characterized by significant swirl for flame stabilization and reduced cooling air mass flows. As a result, substantial spatial and transient variations of the turbine inlet conditions are encountered. To investigate the effect of the combustor on the high pressure turbine, a rotating cooled transonic high-pressure configuration has been designed and investigated experimentally at the DLR turbine test facility ‘NG-Turb’ in Göttingen, Germany. It is a rotating full annular 1.5 stage turbine configuration which is coupled to a combustor simulator. The combustor simulator is designed to create turbine inlet conditions which are hydrodynamically representative for a lean-burn aero engine. A detailed description of the test rig and its instrumentation as well as a discussion of the measurement results is presented in part I of this paper. Part II focuses on numerical modeling of the test rig to further extend the understanding of the measurement results. Integrated simulations of the configuration including combustor simulator and nozzle guide vanes are performed for leading edge and passage clocking position and the effect on the hot streak migration is discussed. The simulation and experimental results at the combustor-turbine interface are compared showing a good overall agreement. The relevant flow features are correctly predicted in the simulations, proving the suitability of the numerical model for application to integrated combustor-turbine interaction analysis.



Author(s):  
Hyung Gon Kim ◽  
Shuichi Torii ◽  
Toshiaki Yano ◽  
Kyu Keun Song

An experimental study was conducted to investigate the atomization characteristics of spray from the effervescent atomizer, which has two-aerator tube. The atomization characteristics were examined through the influence of ALR (Air-to-Liquid Ratio) and the changes of atomizer geometry (nozzle orifice diameter, diffusion angle, mixing chamber volume). PDPA (Phase Doppler Particle Analyzer) was used to evaluate the SMD (Sauter Mean Diameter) and droplet velocity. During the experiments, the mass flow rate of liquid was kept constant at 2.8g/s and the mass flow rate of atomizing air was changed from 0.2 to 0.6g/s. Experimental results showed that SMD is not a linear function of ALR. While SMD is very sensitive to the changes of ALR, the changes of atomizer geometry have little effect on droplet mean diameter. As the effervescent atomizer with two-aerator tube is insensitive to the changes of atomizer geometry, it is expected that the effervescent atomizer with two-aerator tube is capable of requirements of many applications, without the drawbacks of atomization characteristics.



Author(s):  
Seung-chai Jung ◽  
Siwon Yang ◽  
Shaun Kim ◽  
Ik Soo Kim ◽  
Chul-ju Ahn ◽  
...  

Due to increasing environmental concerns, clean technology has become a key feature in industrial gas turbines. Swirler design is directly associated with the combustion performance for its roles in fuel distribution and flame stability. In this study, the development process of three new conceptual swirlers from Samsung Techwin is presented. Each swirler has unique features to enhance fuel-to-air mixing; Swirler 1 uses tangential air-bypass, Swirler 2 minimizes pressure loss using impeller-like design, and Swirler 3 has combined flow characteristics of axial and radial swirlers. Using extensive computational fluid dynamics (CFD) analysis, lead time and cost in manufacturing the prototypes were significantly reduced. The numerical methods were verified with a lab-scale combustion test; particle image velocimetry (PIV) measurement of cold flow, direct flame images, and OH planar laser induced fluorescence (PLIF) images were compared with result of large-eddy simulation (LES), and they showed good agreement. After design optimization using CFD, full-scale combustion tests were performed for all three swirlers. Flame from each swirler was visualized using a cylindrical quartz liner; direct images and OH chemiluminescence images of flames were obtained. Flame stability and blow-off limit at various air load were examined by gradually lowering the equivalence ratio. NOx and CO concentration were measured at the exhaust. All three swirlers satisfied low NOx and CO levels at the design conditions. The performance maps bounded by the NOx and CO limits and blow-off limit were obtained for all swirlers. Further efforts to maximize the combustors performance will be made.



Author(s):  
Bo W. Rhee ◽  
K. S. Ha ◽  
R. J. Park ◽  
J. H. Song

This paper describes the basic design features of the EU-APR1400 reactor core catcher cooling system and its test facility, and the associated scaling analysis model. An assessment of the validity of the scaling analysis using the preliminary performance test result of the test facility is described. This includes comparison of the predicted mass flow rate of the test loop as a function of the heat load to the facility, inlet flow subcooling and system pressure to the experimental results.



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