Set Of Injectors Research Articles

Optimization of a Hydrogen-Fueled Parametric Strut Injector Using an Automated Workflow Computational Fluid Dynamics Method

Abstract A strut injector for burning hydrogen has been optimized using an automated workflow system. In order to choose the optimal set of injectors to cover the design space, an optimized design of experiments (DOE) method was used to automatically choose the parameters that best spanned the design space. One hundred candidate designs were chosen, and a script was used to generate a series of stereolithography (STL) files for each design. The STL files were then uploaded to a supercomputer for computational fluid dynamics analysis. For each of the 100 designs, a four step process was followed to generate the required data, and this included an automated mesh generation step, a field initialization step, a mesh adaptation step, and finally an large eddy simulation all within the yales2 numerical framework. In order to reduce the time required for postprocessing and the amount of data required, the simulations relied heavily on an on-the-fly postprocessing methodology, which reduced the complex time-unsteady flow fields to a small number of quantified outputs of interest that measured the suitability of each design such as the pressure drop across the injector and the efficiency of the mixing process. At the conclusion of these simulations, automated scripts translated these outputs into a smaller set of parameters that could be used to compare each design and allow subsequent optimization and surrogate modeling. Several surrogate modeling methods were attempted with mixed results; however, a simple classification methodology quickly identified the parameters of interest.

A design strategy for water-based noise suppression systems in liquid rocket engines firing tests

This paper presents a streamlined design procedure for water-based noise suppression systems that are applicable to multiple classes of rocket engines. A newly adapted steady quasi-one-dimensional two-phase model is employed to predict the evolution of the exhaust gases interacting with water droplets. Such a model is embedded into a two-step optimization procedure with the objective of finding the most efficient combination of the suppressor operative parameters. This information is then used to design the hardware of the system, which consists in a set of injectors, with the task of producing atomized water jets directed towards the exhaust gases, and a toroidal manifold, with the task of delivering water to the injectors at uniform conditions of pressure and velocity. Finally, the proposed design procedure is applied to a 15 kN thrust class oxygen/methane liquid rocket engine. Technical specifications of the resulting water-based noise suppression system are provided along with a detailed three-dimensional CAD model.

Highly flexible and accurate serial picoinjection in droplets by combined pressure and flow rate control.

Picoinjection is a robust method for reagent addition into microfluidic droplets and has enabled the implementation of numerous multistep droplet assays. Although serial picoinjectors allow to screen many conditions in one run by injecting different combinations of reagents, their use is limited because it is complex to accurately control each injector independently. Here, we present a novel method for flexible, individual picoinjector control that allows to inject a predefined range of volumes by controlling the flow rate of the injector as well as turning off injection by setting the equilibrium pressure, which resulted in a stable interface of the injector liquid with the main microfluidic channel. Robust setting of the equilibrium pressure of an injector was achieved by applying accurate (R2 > 0.94) linear models between the injector and oil pressure in real-time. To illustrate the flexibility of this method, we performed several proof-of-concepts using 1, 2 or 3 picoinjectors loaded with fluorescent dyes. We successfully demonstrated picoinjection approaches using time-invariant settings, in which an injector setting was applied for prolonged times, and time-variant picoinjection, in which the injector settings were continuously varied in order to sweep the injected volumes, both resulting in monodisperse (CV < 3.4%) droplet libraries with different but reproducible fluorescent intensities. To illustrate the potential of the technology for fast compound concentration screenings, we studied the effect of a concentration range of a detergent on single-cell lysis. We anticipate that this robust and versatile methodology will make the serial picoinjection technology more accessible to researchers, allowing its wide implementation in numerous life science applications.

QUANTITATIVE DETERMINATION OF RESIDUAL SOLVENTS IN PALONOSETRON API BY HS-GC METHOD

Objectives: Palonosetron is an antidote to 5-HT3 in the prevention and treatment of chemotherapy-induced nausea and vomiting (CINV). The presence of residual solvents in pharmaceutical drug substances or products, as well as excipients, can have a detrimental effect on the product’s quality and stability. These substances must be evaluated for safety and efficacy. The primary purpose of this work is to establish a method for validating and quantifying residual solvents in palonosetron API using Head Space Gas Chromatography (HS-GC). Methods: In the proposed HS-GC technique for the quantifying residual solvents - ethanol, acetone, methanol, acetonitrile, and isopropyl alcohol (IPA) in Palonosetron API, the headspace equilibrium was achieved at 100°C and analyzed by DB-624 column (30 m × 0.24 mm, 1.8 μm) with injector and detector temperature set at 200°C and 230°C respectively. The dissolving solvent was dimethyl sulfoxide (DMSO). After the initial holding time of 5mins, the temperature was increased to 120°C from 40°C in 20mins at a rate of 10°C/min using a flow rate of 10 ml/min and a split ratio of 1:25 with nitrogen as carrier gas. The approach created has been validated and quantified as per International Conference on Harmonization’s (ICH) guidelines. Results: All the results obtained were within the ICH specified limits. The validation results for repeatability studies (%RSD values) were found to be &lt;10; recovery studies values were in the range of 90–110% and for the selected linearity range 25–150 μg/ml the correlation coefficients(γ2) for all the solvents were observed to be &gt;0.99. Conclusion: A sensitive, simple, precise, and economic HS-GC method with Flame Ionization Detector (FID) was developed and validated to quantitatively determine the residual solvents in Palonosetron API.

Cylindrical Rotating Detonation Engine with Propellant Injection Cooling

A cylindrical rotating detonation engine (24 mm diameter) with multiple injector holes on the combustor side wall for both propellant injection and cooling by injector gas flow was designed and tested. As each set of injectors created its own detonations, the synchronized detonation waves propagated along the three injector rows. From the axial view, those detonation combustion regions stood off from the injector surface as the non-well-mixed propellant existed between the wall and the combustion zone. This combustion region tended to broaden in lateral and radial directions as the mass flow rate increased by pushing its region with the injected propellant. Wall heat flux and heat balance were evaluated by a one-dimensional unsteady heat transfer model with propellant injection cooling. Even when the flow rate was doubled, the increase in the wall heat flux was only 18–25%. This heat trend and the image of standoff self-chemiluminescence from the injector surface implied that a non-well-mixed unburned propellant acted as a heat-reduction layer to ease heat load into the combustor. Measurements and thermal analysis verified the flow structure near the injector and heat-exchange mechanism due to the propellant gas flow, which has a potential for thermal steady operation.

ESTIMATION OF RESIDUAL SOLVENTS IN NETUPITANT API BY HEADSPACE GAS CHROMATOGRAPHY

Objective: Residual solvents are undesirable components present in Active Pharmaceutical Ingredients (API), excipients, or drug products. To meet the specific quality-based requirements, the presence of these solvents in pharmaceutical products should be monitored to ensure their safety. The main objective of this work is to develop a new method for the determination of residual solvents in netupitant API by an HS-GC method with an FID detector. Methods: An automated headspace GC method has been developed and validated for the estimation of the residual solvents-N-methyl pyrrolidine, xylene, toluene, and N, N Dimethylacetamide in netupitant API. The samples were dissolved in dimethyl sulfoxide and the equilibrium headspace gas was formed at 80 ᵒC, which was analyzed using a DB-624 column (30m*0.53 mm, 3.00 µm) with an injector and detector temperature set at 160 ᵒC and 230 ᵒC, respectively. The initial oven temperature was set at 60 ᵒC for 5 min and programmed at a rate of 10 ᵒC/min to the final temperature of 150 ᵒC, with a hold time of 5 min by maintaining the flow rate of 4.0 ml/min with a split ratio of 1:10, and total run time of 20 min. Nitrogen was used as carrier gas. The method developed was validated as per International Conference for Harmonization (ICH) guidelines for repeatability, linearity, range, ruggedness, detection limit, quantification limit, and recovery studies. Results: The linearity range selected was 50-350µg/ml and the correlation coefficient(γ2) values for all the solvents were found to be&gt;0.99; recovery studies values were in a range of 90-110% and %RSD values were also found to be not more than 10 for the solvents. Conclusion: A novel, accurate, sensitive, and simple method was described for estimating residual solvents in Netupitant API by Headspace Gas Chromatography (HS-GC) coupled with a Flame Ionization Detector (FID). Excellent results have been observed for all the validated parameters with good peak resolution and lesser retention times.

PROCEDURE OF MULTI SLICE COMPUTED TOMOGRAPHY (MSCT) THORAX EXAMINATION USING POSITIVE CONTRAST MEDIA WITH BREAST CANCER CASE

Background: The protocol for MSCT Thorax examination is axial/coronal/sagittal. The slice thickness parameter has an important role in examining MSCT Thorax in breast cancer cases using contrast media. The thinner the slice thickness, the better the detailed image obtained. The aim of this study is to explain the MSCT Thorax examination procedure in breast cancer cases using positive contrast media, the role of slice thickness in diagnosis and to find out diagnostic information on the MSCT Thorax examination in cancer cases breast.&#x0D; Methods: This type of research is qualitative with a literature study approach. The data were obtained by identifying the problem then looking for keywords, namely MSCT Thorax, Slice thickness, breast cancer. Literature reviews are carried out through journal search engine searches, such as: Google Scholar, American Journal Rontgenology (AJR), Pubmed, Proquest. The collected journals are reduced based on inclusion criteria so that 3 relevant journals are obtained then analyzed descriptively so that they can answer the objectives to be drawn conclusions.&#x0D; Results: The results of a literature study show that the MSCT Thorax examination procedure in cases of breast cancer using contrast media is fasting 6 hours before the examination, laboratory checks (urea cratinin within normal limits), releasing all metals in the body, CT scan plane, fixation tools, blankets. , contrast media, injector set.&#x0D; Conclusion: Contrast media dosage 1-2 ml / kg body weight, flow rate 2-4 ml / s, concentration 300-350 mgl / ml, patient position supine feet first, upper limit of lung Apex and lower limit of diaphragm (depending on needs), axial cut, coronal, sagittal, the parameters used were kV, mAs, slice thickness, matrix, WW, WL. A thin slice thickness will provide more accurate diagnostic information and a clear picture of metastases and small lesions can be seen.

Evaluation of the Effectiveness of Preloaded IOL Injectors in Surgical Time

Background: The implantation of the intraocular lens (IOL) is still subject to error and complication, as it can result in traumatic opening of the IOL leading to rupture of the posterior capsule and zonular dialysis, it takes time to train paramedic teams to assemble such IOLs with the manual injectors. Moreover, there is a potential risk of comtamination and endophthalmitis as there is manipulation of the IOL and cartridge. The preloaded IOLs tend to reduce those unwanted results and may optimize the surgical time. Purpose: The aim of this study is to compare the effectiveness and implantation time between three injectors and three intraocular lenses, two pre-loaded and one conventional. Methodology: Videos of thirty patients undergoing cataract surgery from December 2019 to December 2020 at the Hospital Oftalmologico de Brasilia (HOB), Brasilia, Brazil were included in this observational, analytical retrospective study, non randomized. All patients had their surgeries recorded, from which the time of injection and opening of the intraocular lens (IOL) was extracted, 20 eyes were implanted with preloaded intraocular lens, and 10 eyes with conventional IOL implant. The patients were divided into three groups with similar eye characteristics. The first received the AutonoMeTM (CE) injector with the Clareon® IOL, the second the IsertTM injector (I) with the Hoya® IOL, and the third was injected with Johnson & Johnson Platinum 1 Series injector used to deliver Sensar® One AAB00 lens. The Welch test and Tukey’s Post Hoc test were used in the statistical analysis. Results: It was observed that there was a statistical significance regarding the presence of a haptic stuck (5 Clareon vs 0 Sensar and Hoya), between the mean opening time of the IOL optics Sensar One, Hoya and Clareon (25.00 vs 31.40 vs 11.70 s, p < 0.001) and between the total time (the injection time more the opening time of the IOL) in relation to Hoya and Clareon lenses (39.50 s vs 19.60 s, p < 0.001); the total time of the Sensar IOL was 31.30 s. The opening time of the IOL optics was significantly longer for the Sensar One and Hoya groups compared to Clareon group, and the total time of Hoya group was significantly longer compared to the total time of the Clareon group. Conclusion: The study demonstrated that the choice of injector and IOL set can significantly affect the total time of IOL implantation. However, there was no difference regarding complications and collateral damage depending on the set chosen for the implant.

A technique for determining pump injector settings for an on-table CT or 3D DSA in interventional radiology

IntroductionOn-Table computed tomography (CT) or 3D digital subtraction angiography (DSA) in interventional radiology (IR) has become a valuable diagnostic tool. MethodsA review of the literature found a poor evidential base supporting the technical parameters for iodinated contrast delivery during these acquisition sequences. Results and conclusionThis technical note presents an easy method of estimating the parameters needed to reliably obtain diagnostic on-table CT or 3D DSA images, whilst attempting minimising contrast dose. Implications for practiceA systematic approach to estimating contrast delivery regimes during on-table CT and 3D DSA can help ensure diagnostic quality images are obtained. Further clinical studies are now required to rigorously evaluate this protocol.

Retrograde CT urethrography using a power injector quantitatively reveals effects of bladder distension on urethral size in healthy male Beagle dogs.

Quantitative analysis of the normal retrograde urethrogram is well reported in radiography, but studies on CT urethrography are lacking. Recently, a method of retrograde CT urethrography using a power injector was described. The purpose of the current, prospective, analytical study was to quantify the urethral size of five, healthy, intact, male Beagle dogs using retrograde CT urethrography and a power injector. With the injection rate of the power injector set at 0.3mL/s, 1mL/kg of diluted contrast medium (15mg I/mL) was injected, and a CT examination was performed. The state of the initial urethrogram taken was defined as "empty bladder." The same procedures were repeated with the injection of an additional 1mL/kg of diluted contrast medium until the ureteral reflux was seen (distended bladder). There was a significant difference in volumes between the empty and distended bladder, but the membranous urethra showed the least difference (P=.0044) among the three regions (P<.0001 for the prostatic and penile urethra). Urethral diameters at six sites were measured from sagittal images, and the sites of measurements were adopted from the earlier radiographic studies. The most significant difference in the urethral diameters between the empty and distended bladder occurred at the cranial and middle prostatic urethra (P<.0001). The results of this study can be useful for interpreting the results of retrograde CT urethrography. Care must be taken when narrowing is suspected at the prostatic urethra, and if necessary, further distension of the urinary bladder should be tried.

Evaluation of the effect of the addition of bioethanol to gas oil on coking diesel engine injector terminals

The article presents the results of empirical research and their analysis regarding the impact of diesel oil and diesel oil mixture with bioethanol on coking the test injector nozzles of the XUD9 engine from PSA. The research included three fuel deals: diesel fuel as the base fuel and diesel oil mix with ONE10 bioethanol (10% bioethanol plus diesel oil (V/V)), ONE20 (20% bioethanol plus diesel oil (V/V)). They were conducted on the basis of CEC PF-023 developed by CEC (Coordinating European Council). Each of the above-mentioned fuels was tested using a new set of injectors. The propensity of the fuel for coking the injector tips was expressed as a percentage reduction in the air flow through the nozzles of each injector for the given sheer increments. The test result was the average percentage of airflow reduction for all nozzles at 0.1 mm spike increments and was measured according to ISO 4010 "Diesel engines. Calibrating nozzle, delay pintle type”. The test results for individual atomizers of the above-mentioned test engine in the area of sediment formation from flowing fuel shown a lower tendency to coke the injectors using diesel fuel-bioethanol in comparison to the use of pure diesel oil. Based on the CEC PF-023 test, it can be noticed that the level of contamination of the tested injectors for ONE10 fuel is about 3% lower, and for ONE20 fuel is about 4% lower than the level of pollution for diesel fuel.

An experimental study into the effect of injector pressure loss on self-sustained combustion instabilities in a swirled spray burner

Combustion instabilities depend on a variety of parameters and operating conditions. It is known, especially in the field of liquid rocket propulsion, that the pressure loss of an injector has an effect on its dynamics and on the coupling between the combustion chamber and the fuel manifold. However, its influence is not well documented in the technical literature dealing with gas turbine combustion dynamics. Effects of changes in this key design parameter are investigated in the present article by testing different swirlers at constant thermal power on a broad range of injection velocities in a well controlled laboratory scale single injector swirled combustor using liquid fuel. The objective is to study the impact of injection pressure losses on the occurrence and level of combustion instabilities by making use of a set of injectors having nearly the same outlet velocity profiles, the same swirl number and that establish flames that are essentially identical in shape. It is found that combustion oscillations appear on a wider range of operating conditions for injectors with the highest pressure loss, but that the pressure fluctuations caused by thermoacoustic oscillations are greatest when the injector head loss is low. Four types of instabilities coupled by two modes may be distinguished: the first group features a lower frequency, arises when the injector pressure loss is low and corresponds to a weakly coupled chamber-plenum mode. The second group appears in the form of a constant amplitude limit cycle, or as bursts at a slightly higher frequency and is coupled by a chamber mode. Spontaneous switching between these two types of instabilities is also observed in a narrow domain.

Hydraulic characteristics of high temperature hydrocarbon liquid jets with various orifice geometries

An experimental study was conducted to investigate the effects of orifice geometry on the hydraulic characteristics of high-temperature aviation fuel jets. Pressurized heated liquid hydrocarbon fuel, simulating fuel used as coolant in the active cooling system of a hypersonic flight vehicle, was injected through a set of plain orifice nozzles of different lengths and diameters. The fuel was heated to close to 573 K (300 °C) using an induction heater at an upstream pressure of up to 1.0 MPa, and discharged to atmospheric downstream pressure conditions. The orifice diameter (D) varies from 0.7 to 1.5 mm and the length (L) from 1.4 to 4.3 mm, which results in length-to-diameter ratios (L/D) from 1.1 to 6.1, and the inlet of the orifice is nominally sharp-edged. Hydraulic characterization in terms of fuel injection temperature (Tinj) was carried out by introducing the discharge coefficient (Cd), and the macroscopic internal flow characteristics were correlated to Reynolds number (Re) and cavitation numbers (K and Ca). The fundamental behaviors of high-temperature liquid fuel jets at the specified operating ranges represented by Cd with respect to Tinj for a given set of injectors revealed that, as Tinj increases above the boiling point, the Cd of the injector with a longer orifice decreases faster than that of a shorter injector of the same orifice diameter, and for injectors of a given orifice length, Cd decreases with Tinj in a similar way irrespective of orifice diameter. Plots of Re vs. Tinj, Cd vs. Re, and Cd vs. K and Ca clearly show the dependence of the cavitation characteristics on the orifice geometry under high temperature injection conditions. In order to quantify the degree of cavitation for various orifice geometries, the Cd vs. Ca curve for each injector configuration has been fitted linearly; the mass flow choking effect in high temperature fuel injection represented by the magnitude of the slope from the linear fit becomes stronger as the orifice is longer in length and/or wider in diameter. This suggests that longer and wider orifices are more susceptible to choked cavitation. It was also found that the geometric effect is maintained for various ΔP, even though the magnitude of the slope increases with ΔP, and the sensitivity of the magnitude to increasing ΔP becomes stronger for longer orifices.

Electron bunch structure in energy recovery linac with high-voltage dc photoelectron gun

The internal structure of electron bunches generated in an injector line with a dc photoelectron gun is investigated. Experiments were conducted on the ALICE (accelerators and lasers in combined experiments) energy recovery linac at Daresbury Laboratory. At a relatively low dc gun voltage of 230 kV, the bunch normally consisted of two beamlets with different electron energies, as well as transverse and longitudinal characteristics. The beamlets are formed at the head and the tail of the bunch. At a higher gun voltage of 325 kV, the beam substructure is much less pronounced and could be observed only at nonoptimal injector settings. Experiments and computer simulations demonstrated that the bunch structure develops during the initial beam acceleration in the superconducting rf booster cavity and can be alleviated either by increasing the gun voltage to the highest possible level or by controlling the beam acceleration from the gun voltage in the first accelerating structure.

Hummingbird: monitoring and analyzing flash X-ray imaging experiments in real time.

Advances in X-ray detectors and increases in the brightness of X-ray sources combined with more efficient sample delivery techniques have brought about tremendous increases in the speed of data collection in diffraction experiments. Using X-ray free-electron lasers such as the Linac Coherent Light Source (LCLS), more than 100 diffraction patterns can be collected in a second. These high data rates are invaluable for flash X-ray imaging (FXI), where aerosolized samples are exposed to the X-ray beam and the resulting diffraction patterns are used to reconstruct a three-dimensional image of the sample. Such experiments require immediate feedback on the quality of the data collected to adjust or validate experimental parameters, such as aerosol injector settings, beamline geometry or sample composition. The scarcity of available beamtime at the laser facilities makes any delay extremely costly. This paper presents Hummingbird, an open-source scalable Python-based software tool for real-time analysis of diffraction data with the purpose of giving users immediate feedback during their experiments. Hummingbird provides a fast, flexible and easy-to-use framework. It has already proven to be of great value in numerous FXI experiments at the LCLS.

GC/MS method for determining carbon isotope enrichment and concentration of underivatized short-chain fatty acids by direct aqueous solution injection of biogas digester samples

In anaerobic digestion of organic matter, several metabolic pathways are involved during the simultaneous production and consumption of short-chain fatty acids (SCFA) in general and acetate in particular. Understanding the role of each pathway requires both the determination of the concentration and isotope enrichment of intermediates in conjunction with isotope labeled substrates. The objective of this study was to establish a rapid and simple GC/MS method for determining the isotope enrichment of acetate and concentration of underivatized short-chain fatty acids (SCFA) in biogas digester samples by direct liquid injection of acidified aqueous samples. Sample preparation involves only acidification, centrifugation and filtration of the aqueous solution followed by direct injection of the aqueous supernatant solution onto a polar column. With the sample preparation and GC/MS conditions employed, well-resolved and sharp peaks of underivatized SCFA were obtained in a reasonably short time. Good recovery (96.6–102.3%) as well as low detection (4–7µmol/L) and quantification limits (14–22µmol/L) were obtained for all the 6 SCFA studied. Good linearity was achieved for both concentration and isotope enrichment measurement with regression coefficients higher than 0.9978 and 0.9996, respectively. The method has a good intra- and inter-day precision with a relative standard deviation (RSD) below 6% for determining the tracer-to-tracee ratio (TTR) of both [2-13C]acetate and [U-13C]acetate. It has also a good intra– and inter-day precision with a RSD below 6% and 5% for determining the concentration of standard solution and biogas digester samples, respectively. Acidification of biogas digester samples with oxalic acid provided the low pH required for the protonation of SCFA and thus, allows the extraction of SCFA from the complex sample matrix. Moreover, oxalic acid was the source of formic acid which was produced in the injector set at high temperature. The produced formic acid prevented the adsorption of SCFA in the column, thereby eliminating peak tailing and ghost peaks. The applicability of the validated GC/MS method for determining the concentration of acetate and its 13C isotope enrichment in anaerobic digester samples was tested and the results demonstrated the suitability of this method for identifying the metabolic pathways involved in degradation and production of acetate.

Spectroscopic analysis of the phases of premixed combustion in a compression ignition engine fuelled with diesel and ethanol

The premixed charge compression ignition (PCCI) combustion represents a possible solution for decreasing the pollution with respect to diesel engine, while maintaining the efficiency rate at values that are comparable, and in some cases higher, than those of a diesel engine. This paper investigates the operation of an optical-access compression ignition engine (bore: 82mm, stroke: 90mm) running at PCCI combustion with neat bio-ethanol and European commercial diesel fuel injected in the intake manifold and into the cylinder, respectively. In its original configuration, the engine burned diesel and this case was used as reference of compression ignition combustion. Then, different amounts of bio-ethanol were injected varying the energizing time of the injector set in the intake manifold. This allowed to create PCCI combustion with high levels of pre-combustion mixing, and to ensure low equivalence ratio and low flame temperatures too. Moreover, both the amount and the start of diesel injection was varied to investigate their effects on the several combustion phases. UV–Visible imaging and spectroscopic measurements were performed in the engine and the autoignition of the charge, the combustion process and the chemical species involved were detected and analysed. In particular, optical diagnostics allowed to observe how the mixture burned: no luminous flame emission in the visible range was recorded; while in the ultraviolet wavelength range numerous species, like HCO, HCOH, OH, and CO and others were detected. Varying the in-cylinder premixed ratio the combustion retarded and the rate of heat release passed from single to three-phase premixed combustion, so revealing a phase due to intermediate temperature reactions. The same behavior was observed varying the start of injection and the quantity of diesel that affected the premixed ratio. Spectroscopic measurements revealed that during the intermediate temperature heat release large amount of OH radical governed the start of combustion of the charge. It was also observed that the preignition combustion was mainly due to the stratified mixing of the diesel fuel close to the bowl wall. Finally the presence of OH radical was monitored for the whole combustion process.

Characterization and Modeling of a Spinning Thermoacoustic Instability in an Annular Combustor Equipped With Multiple Matrix Injectors

Oscillations in fully annular systems coupled by azimuthal modes are often observed in gas turbine combustors but not well documented. One objective of the present study is to characterize this type of oscillation in a laboratory scale system, allowing detailed pressure measurements and high speed visualization of the flame motion. The experiment is designed to allow detailed investigations of this process at a stable limit cycle and for an extended period of time. Experiments reported in the present article are carried out in the MICCA facility which was used in our previous work to analyze instabilities arising when the chamber backplane was equipped with multiple swirling injectors (Bourgouin et al., 2013, “Self-Sustained Instabilities in an Annular Combustor Coupled by Azimuthal Acoustic Modes,” ASME Paper No. GT2013-95010). In the present study, these units are replaced by a set of matrix injectors. The annular plenum feeds 16 such devices confined by two cylindrical quartz tubes open to the atmosphere. The multiple flames formed by the matrix injectors are laminar and have a well documented describing function. This constitutes an ideal configuration allowing systematic investigations of thermo-acoustic oscillations coupled by longitudinal or azimuthal modes while avoiding complexities inherent to swirling turbulent flames studied previously. Optical access to the chamber allows high speed imaging of light emission from the flames providing instantaneous flame patterns and indications on the heat release rate fluctuations. Eight waveguide microphones record the pressure signal at the combustor injection plane and in the plenum. Among the unstable modes observed in this setup, this analysis focuses on situations where the system features a spinning azimuthal mode. This mode is observed at a frequency which is close to that associated with the 1A mode of the plenum. A theoretical analysis is then carried out to interpret the angular shift between the nodal lines in the plenum and chamber, and the measured flame describing function (FDF) is used to quantify this shift and determine the linear growth rate.

Characterization of a Set of ECN Spray A Injectors: Nozzle to Nozzle Variations and Effect on Spray Characteristics

The Engine Combustion Network (ECN) is becoming a leading group concerning the experimental and computational analysis of Engine combustion. In order to establish a coherent database for model validation, all the institutions participating to the experimental effort carry out experiments at well-defined standard conditions (in particular at Spray A conditions: 22.8kg/m3, 900K, 0% and 15% O2) and with Diesel injectors having the same specifications. Due to the rising number of ECN participants and also to unavoidable damages, additional injectors are required. This raises the question of injector's characteristics reproducibility and of the appropriate method to introduce such new injectors in the ECN network. In order to investigate this issue, a set of 8 new injectors with identical nominal Spray A specification were purchased and 4 of them were characterized using ECN standard diagnostics. In particular, the measurements include the nozzle hole diameter, the rate of injection, the liquid and vapor penetrations, the auto-ignition delay and the lift-off length. Variations of ambient temperature, oxygen concentration and density have also been performed. In general the results show similar behavior to ECN standard injectors, confirming that this set of new injectors can be integrated into the pool of ECN injectors. However, discrepancies between spray characteristics were observed, although the injector specifications and the boundary conditions were sensibly the same. The sources of variations from injector to injector are analyzed in order to provide new information on the reproducibility of injectors characteristics, and improve the comparison methodology between experimental data and simulation.

A New SAGD-Well-Pair Placement: A Field Case Review

Summary Steam-assisted gravity drainage (SAGD) has been improved consistently by experimenting with various solutions in both oil sands and heavy-oil fields in Canada (Butler 1994; Singhal et al. 1998). The SAGD process consists of two stacked horizontal wells and is proven technology in heavy-oil fields (Butler and Yee 2000). Employing the same concept of gravity drainage, SAGD-well placement convention has been revisited and challenged many times (Birrell and Putnam 2000; Edmunds 1991; Parappilly and Zhao 2009). Known to the industry, the cross-SAGD (also called XSAGD) (Stalder 2007) and J-shaped well steam-assisted gravity drainage (JAGD) (Larter et al. 2008) processes are two examples of fit-for-purpose well design and recovery schemes that require unique drilling practices. The Celtic pool, located in Lloydminster, Saskatchewan, is an active Husky Energy Incorporated (Husky) thermal field that includes 31 SAGD well pairs. In this heavy-oil pool, one of the SAGD well pairs (I3/I4; Well I3 as producer and Well I4 as the injector) experienced production downtime soon after coming into service. Following numerous unsuccessful service jobs, several re-entry options were suggested in order to recover remaining reserves. These included sidetracking Well I3, redrilling a new well from the same pad location, or commencing a new well from a different surface location. These cases were ranked, and in 2010, on the basis of a drilling-risk assessment, the new horizontal producer well (I3A) was drilled close to the existing well pair. Well I3A was placed counter currently below the existing injector well (I4) and set successfully parallel to the abandoned Well I3. Steam conditioning was completed in the first quarter (Q) of 2011, and the new SAGD well pair (I3A/I4) has been put on production successfully. The new well pair was positioned in the opposite direction of a conventional SAGD-well-pair placement. This paper presents the original I3/I4 pair performance, the challenges, results of redrilling Well I3A, reservoir-simulation study, and recent field production of the I3A/I4 SAGD well pair.