The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
Seoksu Moon - One of the best experts on this subject based on the ideXlab platform.
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the gasoline atomization characteristics and Static Pressure distribution of tapered nozzle swirl spray
Transactions of The Korean Society of Mechanical Engineers B, 2007Co-Authors: Seoksu Moon, Jaejoon ChoiAbstract:The Static Pressure distribution, atomization characteristics and velocity distribution of tapered nozzle swirl spray is analyzed and then compared with original swirl spray. The Static Pressure distribution inside the swirl spray is measured using a piezoresistive Pressure transducer. Phase Doppler anemometry (PDA) is applied to measure and analyze the droplet size and velocity distribution of tapered nozzle and original swirl spray. The Static Pressure inside the spray shows the lower value compared to the atmospheric Pressure and this Pressure drop is getting attenuated as the taper angle is increased. The droplet size of tapered nozzle spray shows similar value compared to the original swirl spray at the horizontal mainstream while it shows increased value at vertical mainstream. The deteriorated atomization characteristics of tapered nozzle spray is improved by applying high fuel temperature injection without causing the spray collapse. The velocity results show that the larger portion of fuel is positioned with higher injection velocity, and the smaller portion of fuel is positioned with lower injection velocity with causing spatially non-uniform mixture distribution.
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the Static Pressure distribution and flow characteristics inside the high Pressure swirl spray
Journal of ILASS-Korea, 2006Co-Authors: Seoksu Moon, Essam Aboserie, Jaejoon ChoiAbstract:The Static Pressure distribution and flow characteristics inside the high-Pressure swirl spray were investigated by measuring the Static Pressure inside the spray and applying the computational fluid dynamics (CFD). The Static Pressure difference between inner and outer part of spray was measured at different axial locations and operating conditions using a piezo-resislive Pressure transducer. To obtain the qualitative value of swirl motion at different operating conditions, the spray impact-Pressure at the nozzle exit was measured using a piezo-electric Pressure transducer, and the flow angle was measured using a microscopic imaging system. The flow characteristics inside the high Pressure swirl spray was simulated by the 1-phase 3-dimensional CFD model. The effect of Pressure alternations on spray development was discussed with macroscopic spray images and a mathematical liquid film model. The results showed that the Static Pressure drop is observed inside the swirl spray as a result of the dragged air motion and the centrifugal force of the air. The recirculation vortex inside the spray was also observed inside the swirl spray as a result of the adverse Pressure gradient along the axial locations. The results of analytical liquid film model and macroscopic spray images showed that the Static Pressure structure is one of the main parameters affecting the swirl spray development.
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paper id iclass 06 113 Static Pressure distribution inside the swirl spray
2006Co-Authors: Seoksu Moon, Essam Aboserie, Hyun Dong ShinAbstract:The transient Static Pressure of the air located along the centerline of the spray from a DISI Pressure swirl injector was measured for different injection Pressures, fuel temperatures and injection durations. The drop in the Pressure at the centerline was found to be mainly attributed to the swirling liquid and enhanced with the swirling velocity manifested by the injection Pressure. With increasing the injection duration, the Pressure was found to be continuously dropped, although the measured swirling momentum of the liquid reaches an asymptotic value and remains constant until the needle starts to close. This implies that the Pressure at the centerline of a transient spray does not reach its asymptotic value which corresponds to the case of a continuously injected spray. At higher fuel temperature, the air Pressure at the centerline increases and can reach a value more than atmospheric Pressure due to the sudden evaporation of the fuel after been released underneath the needle. This high air Pressure pushes the main stream of the spray to the radial direction resulting in a larger nozzle spray angle which is soon collapsed after a short distance due to the severe expansion of the air and enhanced swirling motion. The link between the Pressure drop across the spray and liquid film profile for different operating conditions was presented using a simple analytical model. The injector was then modified to eliminate the Pressure drop at the center line to have a robust spray that has limited variation with the operating condition and can be used in spray guided gasoline direct injection system. By cutting the nozzle to have a tapered nozzle with an angle less than the flow angle the opened hollow cone shape along the spray streamlines was formed. This shape assists in equalizing the Pressure between the centerline and outer part of spray envelop. The results showed that there is a potential from tapered nozzle spray to be independent of the operating conditions without much sacrifice of the atomization quality.
Jaejoon Choi - One of the best experts on this subject based on the ideXlab platform.
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the gasoline atomization characteristics and Static Pressure distribution of tapered nozzle swirl spray
Transactions of The Korean Society of Mechanical Engineers B, 2007Co-Authors: Seoksu Moon, Jaejoon ChoiAbstract:The Static Pressure distribution, atomization characteristics and velocity distribution of tapered nozzle swirl spray is analyzed and then compared with original swirl spray. The Static Pressure distribution inside the swirl spray is measured using a piezoresistive Pressure transducer. Phase Doppler anemometry (PDA) is applied to measure and analyze the droplet size and velocity distribution of tapered nozzle and original swirl spray. The Static Pressure inside the spray shows the lower value compared to the atmospheric Pressure and this Pressure drop is getting attenuated as the taper angle is increased. The droplet size of tapered nozzle spray shows similar value compared to the original swirl spray at the horizontal mainstream while it shows increased value at vertical mainstream. The deteriorated atomization characteristics of tapered nozzle spray is improved by applying high fuel temperature injection without causing the spray collapse. The velocity results show that the larger portion of fuel is positioned with higher injection velocity, and the smaller portion of fuel is positioned with lower injection velocity with causing spatially non-uniform mixture distribution.
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the Static Pressure distribution and flow characteristics inside the high Pressure swirl spray
Journal of ILASS-Korea, 2006Co-Authors: Seoksu Moon, Essam Aboserie, Jaejoon ChoiAbstract:The Static Pressure distribution and flow characteristics inside the high-Pressure swirl spray were investigated by measuring the Static Pressure inside the spray and applying the computational fluid dynamics (CFD). The Static Pressure difference between inner and outer part of spray was measured at different axial locations and operating conditions using a piezo-resislive Pressure transducer. To obtain the qualitative value of swirl motion at different operating conditions, the spray impact-Pressure at the nozzle exit was measured using a piezo-electric Pressure transducer, and the flow angle was measured using a microscopic imaging system. The flow characteristics inside the high Pressure swirl spray was simulated by the 1-phase 3-dimensional CFD model. The effect of Pressure alternations on spray development was discussed with macroscopic spray images and a mathematical liquid film model. The results showed that the Static Pressure drop is observed inside the swirl spray as a result of the dragged air motion and the centrifugal force of the air. The recirculation vortex inside the spray was also observed inside the swirl spray as a result of the adverse Pressure gradient along the axial locations. The results of analytical liquid film model and macroscopic spray images showed that the Static Pressure structure is one of the main parameters affecting the swirl spray development.
B R Gelfand - One of the best experts on this subject based on the ideXlab platform.
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positive end expiratory Pressure adjustment in parenchimal respiratory failure Static Pressure volume loop or transpulmonary Pressure
Journal of Clinical Gastroenterology, 2014Co-Authors: A I Iaroshetskiĭ, D N Protsenko, N A Rezepov, B R GelfandAbstract:OBJECTIVE The aim of the study was compare the prognostic value, efficacy and safety ofpositive end-expiratory Pressure (PEEP) adjustment in conformity with lower inflection point of Static "Pressure-volume" loop (LIP) or end-expiratory esophageal Pressure (EEEP) in parenchymal respiratory failure. METHODS We included in the study 56 patients (39 males) at age 47 +/- 17.8 years with parenchymal respiratory failure (PaO2/FiO2 < 250 mmHg, bilateral infiltrates on chest X-ray or lung CT scan, no signs of left ventricular failure), who were mecAanically ventilated for less than 48 hours. All patients were sedated and paralyzed. We measured intra- Sabdominal Pressure, PaO2/FiO2, PaCO2, alveolar dead space (Vdalv), plotted Static "Pressure-volume" loop by low flow technique in range of 0 to 40 mbar, recording LIP Then we placed nasogastric tube with balloon for esophageal Pressure measurement and measured esophageal Pressure at PEEP range from 8 to 20 mbar (with 2 mbar steps) and recorded plateau Pressure (Pplat), transpulmonary plateau Pressure (Ptp plat), transpulmonary Pressure at PEEP level (Ptp PEEP), Static compliance of respiratory system (Cstat), lung compliance (Clung), chest wall compliance (Ccw) at every step. Also by volumetric capnography technique we measured end-tidal carbon dioxide concentration (EtCO2), minute volume of exhaled carbon dioxide (VCO2) volume of exhaled carbon dioxide by single breath (VtCO2) and calculate VC2/EtCO2 as a surrogate marker of pulmnonary perfusion. After that we set PEEP at EEEP level (at zero end-expirato- my ranspulmonary Pressure) and recorded changes of PaO2/FiO2 and Vdalv. RESULTS LIP value was 5 (6-10) mbar and it was less than empirically set PEEP in most of patients before enrollment and had no prognostic value for PEEP setting. EEEP level was 14 (12-18.25) mbar and it was higher than LIP in 96.4% patients. Distribution of EEEP values was close to normal unlike LIP Chest wall compliance was less than normal (100 ml/mbar) in 46% of patients. EEEP has correlation with body mass index (rho 0.554, p=0.002). We did not find any correlation between intra-abdominal pres- sure (IAP) and EEEP (p=0.376) or IAP and LIP (p=0.464). PEEP levels higher than 14 mbar led to significant decrease in Cstat and Clung (p<0.001). We observed significant decrease in VCO at PEEP levels more than 16 mbar, i.e., more than EEEP median. PEEP levels more than 16 mbar decreased VCO2/EtCO2, (decreased pulmonary perfusion) from 7.47 (6.54-8.7) at PEEP 14 mbar to 7.32 (6.35-8.76) at PEEP 20 mbar (p=0.004). PEEP setting at EEEP level increased PaO/FiO2 from 205 (154-235) to 280 (208-358) mmHg (p<0.001), did hot change Vdalv (p=0.093) and decreased Cstat and Clung in the most of patients (64.3%). CONCLUSION L1P was lower than empirically set PEEP in most patients and did not help to optimize gas exchange. PEEP setting at EEEP level in patients with parenchimal respiratory failure increases PaO/FiO, (reflects opening of collapsed alveoli), decreases volume of expired carbon dioxide and decreases lung compliance (reflects overdistenion of opened alveoli). VCO2/EtCO2 ratio decreases (decreased pulmonary perfusion) at PEEP levels more than 16 mbar, which was more than EEEP.
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significance of Static Pressure volume loop and lung computed tomography for differential diagnostics of parenchymal respiratory insufficiency
Journal of Clinical Gastroenterology, 2013Co-Authors: A I Iaroshetskiĭ, D N Protsenko, O V Ignatenko, E S Larin, E V Novoselova, Sulimova Iiu, B R GelfandAbstract:UNLABELLED Purpose of the study was to determine a significance of Static Pressure-volume loop and lung computed tomography for differential diagnostics of parenchymal lung failure developing during mechanical ventilation. MATERIALS AND METHODS 75 patients (42 males and 33 females) with acute lung failure due to parenchymal lung injury during mechanical ventilation were included in to the research. Criteria of including into the research were age over 15, ARDS symptoms absence before respiratory support beginning and modified American-European Consensus Conference ARDS criteria presence during mechanical ventilation (AECC ARDS criteria, 1994--PaO2/FiO2 < 250 mmHg). Lung computed tomography (CT), Static compliance and plateau measurement were performed in all patients. Static Pressure-volume loop was plotted in 23 patients. RESULTS diffuse alveolar damage was diagnosed by CT in 24.3% of patients and "wet sponge" symptom in 10.7% of patients. Dorsal atelectasis (77.3%) and ventilator-associated pneumonia (VAP) (82.7%) were diagnosed in most of patients with AECC ARDS criteria. Sensitivity and specificity of PaO2/FiO2 ratio were too low for diagnostics of ARDS (AUROC 0.67) Patients with diffuse alveolar damage had plateau Pressure 25 mbar (95% CI 22-32), while patients with local lung injury (VAP or atelectasis) had significantly lower plateau Pressure--20 mbar (95% CI 18-22) (p = 0.014). Elevation of plateau Pressure over 30 mbar predicted diffuse alveolar damage with specificity of 100%. Lower inflection point values on the Static Pressure-volume loop was higher in patients with diffuse alveolar damage than in patients with local lung injury--12 mbar (95% CI 7-17) vs. 6 mbar (95% CI 5-10), (p = 0.042, n = 23). Effective (linear) compliance had poor prognostic value for differential diagnostics of acute respiratory failure due to parenchimal lung injury (p = 0.023). CONCLUSION Lung CT plays leading role in differential diagnostics of parenchymal lung failure developing during mechanical ventilation. In the luck of CT scan elevation of plateau Pressure over 30 mbar and values of lower inflection point on the Static Pressure-volume loop over 12 mbar can predict ARDS.
Jing Li - One of the best experts on this subject based on the ideXlab platform.
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a study on the modeling of Static Pressure distribution of wet gas in venturi
Aiche Journal, 2015Co-Authors: Peining Yu, Xili Ba, Ying Xu, Jing LiAbstract:A model for gas–liquid annular and stratified flow through a standard Venturi meter is investigated, using the two-phase hydrokinetics theory. The one-dimensional momentum equation for gas has been solved in the axial direction of Venturi meters, taking into consideration the factors including the void fraction, the friction between the two phases and the entrainment in the gas core. The distribution of wet gas Static Pressure between the two Pressure tapings of the Venturi meters has been modeled in the Pressure range of 0.1–0.6 MPa. Compared with the experimental data, all the relative deviations of the predicted points by the model were within ±15%. As the model is less dependent on the specific empirical apparatus and data, it provides the basis for further establishing a flow measurement model of wet gas which will produce fewer biases in results when it is extrapolated. © 2014 American Institute of Chemical Engineers AIChE J, 61: 699–708, 2015
Jeung Sang Go - One of the best experts on this subject based on the ideXlab platform.
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measuring the distribution of the wall temperature and Static Pressure in a narrow flow gap using a sensor embedded thin plate
Sensors and Actuators A-physical, 2017Co-Authors: Bo Wang, Jeung Sang GoAbstract:Abstract Compact thermo-fluidic systems with complex and narrow gap flow passages, such as heat exchangers, are attractive for use in high energy efficiency applications. However, the narrow gap flow passage limits the experimental evaluations as a result of the size of the commercial sensors and the numerical evaluations of the full model due to massive computational meshes. This paper presents a new method to measure the distribution of the Static Pressure and wall temperature in the narrow gap. The 300 μm-thick stainless steel plate embedded with thermocouple temperature sensors and Pressure tapping holes connected with microchannels is fabricated, and the temperature and Pressure measurements are calibrated through comparisons with commercial sensors. In the experimental evaluation, the 23 flat plates are stacked with a narrow gap and the sensor-embedded plate is placed in the center. Then, the stacked plate thermo-fluidic system is installed in a wind tunnel. The measurement of the Static Pressure and wall temperature distributions in the narrow gap is performed successfully for the increased inlet flow velocities. The Static Pressures are measured at five different micro tapping holes, and the measurements exhibit a standard deviation of ±3.51 Pa for the same inlet velocity. Furthermore, the wall temperatures have good agreement with the reference temperatures measured at the inlet.
