The Experts below are selected from a list of 43251 Experts worldwide ranked by ideXlab platform
Zheng Jian - One of the best experts on this subject based on the ideXlab platform.
-
Influence of Different Air Inlet velocity on Flow Field for Ramjet
Computer Simulation, 2011Co-Authors: Zheng JianAbstract:The Air Inlet velocity has an affect on the secondary combustion of gas in combustor.The 3D reaction flow in secondary combustion chamber of unchoked solid rocket ramjet with dual-underside Air-Inlet was numerically simulated by using k-e turbulent model and PDF combustion model.The effect of the mach number of the Air-Inlet on combustion flow field was analyzed.The results show that with the increase of Air Inlet mach number,the eddy in the secondary combustion chamber was enhanced,but the Air stay time was shorten,under the action of factors,the diffuseness of Air to the head was reduced,the axial velocity increased and the palace of reaction moved backward with the increase of Air Inlet mach number.The wall temperature of the secondary combustion chamber was increased with the increase of mach number,but the affection was weak,in the other hand,the wall pressure was increased strongly.The conclusions provides reference for the fuel gas dual-injection ramjet engine.
Dongmei Huang - One of the best experts on this subject based on the ideXlab platform.
-
Interaction effect of room opening and Air Inlet on solar chimney performance
Applied Thermal Engineering, 2019Co-Authors: Long Shi, Xudong Cheng, Lihai Zhang, Guomin Zhang, Dongmei HuangAbstract:Abstract Solar chimney has been frequently adopted in buildings to save energy by enhancing the natural ventilation. Although its optimization studies have been frequently taken previously, most of them have focused on the configuration of solar chimney but ignored the Air Inlet, even though its significant influence has already been confirmed. The interaction between the Air Inlet and room openings (e.g. window and door) is critical to improving the solar chimney performance, but the related interaction mechanism is still not known. Interaction of room opening and Air Inlet on solar chimney performance was analysed under both natural ventilation and smoke exhaustion modes. Numerical results of 19 scenarios were first validated by reduced-scale experiment tests. Another 25 numerical scenarios for full-scale solar chimney room with different heights of Air Inlet (0.1–2.3 m) and window (0.6–1.8 m) were analysed. It was known from numerical results that the height of window shows limited influence on flow rate under natural ventilation mode but the obvious effect on both flow rate at the Air Inlet and the total flow rate (both window and Air Inlet) under smoke exhaustion mode, especially when the window centre is higher than wall centre. Scenario, when both the window and Air Inlet are at the vertical centre of the wall, shows the best performance of both natural ventilation and smoke exhaustion. An empirical model was also developed to predict the flow rate through the Air Inlet under smoke exhaustion. Critical conditions for Air Inlet to exhaust smoke were determined which happens when the neutral plane is almost no lower than the window centre.
Jonathan A Raper - One of the best experts on this subject based on the ideXlab platform.
-
effect of design on the performance of a dry powder inhaler using computational fluid dynamics part 2 Air Inlet size
Journal of Pharmaceutical Sciences, 2006Co-Authors: Matthew S Coates, Hakkim Chan, Jonathan A Raper, David F FletcherAbstract:ABSTRACT: This study investigates the effect of Air Inlet size on (i) the flowfield generated in a dry powder inhaler, and (ii) the device-specific resistance, and the subsequent effect on powder deagglomeration. Computational fluid dynamics (CFD) analysis was used to simulate the flowfield generated in an Aerolizer® with different Air Inlet sizes at 30, 45, and 60 l/min. Dispersion performance of the modified inhalers was measured using mannitol powder and a multistage liquid impinger at the same flow rates. The Air Inlet size had a varying effect on powder dispersion depending on the flow rate. At low flow rates (30 and 45 l/min), reducing the Air Inlet size increased the inhaler dispersion performance by increasing the flow turbulence and particle impaction velocities above their critical levels for maximal powder dispersion. At 60 l/min, reducing the Air Inlet size reduced the inhaler dispersion performance by releasing a large amount of powder from the device before the turbulence levels and particle impaction velocities could be fully developed. The results demonstrate that the maximal inhaler dispersion performance can be predicted if details of the device flowfield are known. © 2006 Wiley-Liss, Inc. and the American Pharmacists Association
-
Effect of design on the performance of a dry powder inhaler using computational fluid dynamics. Part 2: Air Inlet size.
Journal of pharmaceutical sciences, 2006Co-Authors: Matthew S Coates, Hakkim Chan, David F Fletcher, Jonathan A RaperAbstract:This study investigates the effect of Air Inlet size on (i) the flowfield generated in a dry powder inhaler, and (ii) the device-specific resistance, and the subsequent effect on powder deagglomeration. Computational fluid dynamics (CFD) analysis was used to simulate the flowfield generated in an Aerolizer with different Air Inlet sizes at 30, 45, and 60 l/min. Dispersion performance of the modified inhalers was measured using mannitol powder and a multistage liquid impinger at the same flow rates. The Air Inlet size had a varying effect on powder dispersion depending on the flow rate. At low flow rates (30 and 45 l/min), reducing the Air Inlet size increased the inhaler dispersion performance by increasing the flow turbulence and particle impaction velocities above their critical levels for maximal powder dispersion. At 60 l/min, reducing the Air Inlet size reduced the inhaler dispersion performance by releasing a large amount of powder from the device before the turbulence levels and particle impaction velocities could be fully developed. The results demonstrate that the maximal inhaler dispersion performance can be predicted if details of the device flowfield are known.
James R. Hussey - One of the best experts on this subject based on the ideXlab platform.
-
An investigation of Air Inlet types in mixing ventilation
Building and Environment, 2007Co-Authors: Eungyoung Lee, Jamil A. Khan, Charles E. Feigley, Mallik Ahmed, James R. HusseyAbstract:Abstract Previous studies have shown that dispersion of contaminant concentrations strongly depends on Air Inlet types. However, these studies were performed computationally, not experimentally. Thus, the purpose of the current research is to obtain contaminant concentrations in a room, to perform qualitative and quantitative comparison for a wall jet (WJ) Air Inlet and a ceiling diffuser (CD) Air Inlet, and to determine more efficient Inlet and outlet configuration. Here, the effect of Air Inlet types in mixing ventilation was investigated in an experimental room under two conditions, with no occupant and with an occupant present north of the source. A heated mannequin, producing a total heat load of 120 W, represented an occupant. Tracer gas (99.5% propylene) concentrations were monitored automatically at 144 sampling points with a photoionization detector. Three flow rates (5.5, 3.3, and 0.9 m3/min) were employed. Experimental results for the 0.9 m3/min are not reported here because concentration measurements with time in preliminary tests did not reach a stationary condition even over periods of 5 h due to dominant Airflow by natural convection rather than by forced convection. Results have shown that the Air Inlet type is an important physical determinant to the distribution of Airborne contaminant concentrations because they generate different Airflow patterns and thus different spatial concentration patterns. This investigation enhanced understanding of the interactions of concentration field, Airflow, and Air Inlet types. The findings of the study can be applied to practical areas; for example, it was shown that CD Air supply system minimizes occupant exposure from hazards in office buildings, hospitals, and schools, if sources are located under ceiling diffuser Inlets.
Long Shi - One of the best experts on this subject based on the ideXlab platform.
-
Interaction effect of room opening and Air Inlet on solar chimney performance
Applied Thermal Engineering, 2019Co-Authors: Long Shi, Xudong Cheng, Lihai Zhang, Guomin Zhang, Dongmei HuangAbstract:Abstract Solar chimney has been frequently adopted in buildings to save energy by enhancing the natural ventilation. Although its optimization studies have been frequently taken previously, most of them have focused on the configuration of solar chimney but ignored the Air Inlet, even though its significant influence has already been confirmed. The interaction between the Air Inlet and room openings (e.g. window and door) is critical to improving the solar chimney performance, but the related interaction mechanism is still not known. Interaction of room opening and Air Inlet on solar chimney performance was analysed under both natural ventilation and smoke exhaustion modes. Numerical results of 19 scenarios were first validated by reduced-scale experiment tests. Another 25 numerical scenarios for full-scale solar chimney room with different heights of Air Inlet (0.1–2.3 m) and window (0.6–1.8 m) were analysed. It was known from numerical results that the height of window shows limited influence on flow rate under natural ventilation mode but the obvious effect on both flow rate at the Air Inlet and the total flow rate (both window and Air Inlet) under smoke exhaustion mode, especially when the window centre is higher than wall centre. Scenario, when both the window and Air Inlet are at the vertical centre of the wall, shows the best performance of both natural ventilation and smoke exhaustion. An empirical model was also developed to predict the flow rate through the Air Inlet under smoke exhaustion. Critical conditions for Air Inlet to exhaust smoke were determined which happens when the neutral plane is almost no lower than the window centre.
