The Experts below are selected from a list of 129 Experts worldwide ranked by ideXlab platform
Michael J. Ellenbecker - One of the best experts on this subject based on the ideXlab platform.
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Effects of work practices and upper body movements on the performance of a laboratory fume Hood
Journal of Chemical Health and Safety, 2016Co-Authors: Michael J. Ellenbecker, Susan R Woskie, L DiberardinisAbstract:A Hood user's work practices and upper body movements can adversely affect the performance of a laboratory fume Hood. To quantify the possible effects, Hood performance was measured while simulating typical user activities scenarios. The tested variables were two sash opening heights, two Hood clutter settings, two thermal loads, and three hand–arm–trunk motions, totaling 24 (2 × 2 × 2 × 3) different test conditions. Hood Face velocity was maintained at 0.5 m/s for all tests, using a fan speed controller. For each test condition, the Hood's performance was evaluated using the ASHRAE 110-1995 tracer gas test method. Duplicate measurements were made for each condition, so that a total of 48 tests were conducted, in random order. Three-way ANOVA was performed to find significant effects of work practices and upper body movements on breathing concentrations. The degree of sash opening was the most significant factor affecting Hood performance, followed by hand–arm–trunk motions and thermal load. The effect of Hood clutter was not statistically significant, but the interaction effect with other factors was. The highest breathing concentration value occurred during the test with the sash fully open, arms-down posture, thermal load present, and Hood clutter present. These conditions created complex airflow patterns inside the Hood that resulted in leakage into the breathing zone. Although the test conditions were limited, the results of this study suggest that good work practices in combination with good Hood design and adequate Face velocity can significantly reduce worker exposure. Reducing sash height while working in front of a laboratory fume Hood is vital to reducing potential exposure to the air contaminant generated inside the Hood.
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A new quantitative method for testing performance of in-use laboratory chemical fume Hoods
Journal of Chemical Health and Safety, 2016Co-Authors: Michael J. Ellenbecker, Susan R Woskie, L DiberardinisAbstract:The American Society of Heating and Air-Conditioning Engineers (ASHRAE) 110-1995 tracer gas test method is a well-established measure of laboratory chemical Hood performance, but it requires expensive equipment and trained personnel. This study proposes a new quantitative method for testing laboratory chemical fume Hood performance using materials commonly found in laboratories. The method uses dry ice and warm water to generate visible fog and carbon dioxide (CO2) gas, and then measures chemical fume Hood leakage with a CO2 detector. The fog can also be used as a visual aid to train workers in proper Hood use. To compare the new method with the ASHRAE 110-1995 tracer gas method, both were used to test a conventional by-pass laboratory chemical fume Hood under eight typical use conditions (comprised of different sash opening heights, thermal loads, and Hood clutter). Average Hood Face velocity was maintained at 0.5 m/s (100 ft/min) ± 1% throughout all tests. The test results of the new method were comparable to those of the ASHRAE 110-1995 method. A significant regression equation was found in this study (F(1,6) = 36.15, p = 0.001), with R2 of 0.858: SF6 breathing concentration (in ppb) is equal to −118.184 + 0.912 × CO2 leakage values (in ppm). Using this regression equation, CO2 leakage can be used to estimate SF6 breathing zone concentrations. Ultimately, the new method is cheaper and easier to use than the ASHRAE 110-1995 method for routine Hood performance evaluation.
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Evaluation of leakage from fume Hoods using tracer gas, tracer nanoparticles and nanopowder handling test methodologies.
Journal of Occupational and Environmental Hygiene, 2014Co-Authors: Kevin H. Dunn, Candace Su-jung Tsai, James S. Bennett, Susan R Woskie, Alberto Garcia, Michael J. EllenbeckerAbstract:The most commonly reported control used to minimize workplace exposures to nanomaterials is the chemical fume Hood. Studies have shown, however, that significant releases of nanoparticles can occur when materials are handled inside fume Hoods. This study evaluated the performance of a new commercially available nano fume Hood using three different test protocols. Tracer gas, tracer nanoparticle, and nanopowder handling protocols were used to evaluate the Hood. A static test procedure using tracer gas (sulfur hexafluoride) and nanoparticles as well as an active test using an operator handling nanoalumina were conducted. A commercially available particle generator was used to produce sodium chloride tracer nanoparticles. Containment effectiveness was evaluated by sampling both in the breathing zone (BZ) of a mannequin and operator as well as across the Hood opening. These containment tests were conducted across a range of Hood Face velocities (60, 80, and 100 ft/min) and with the room ventilation system tur...
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articles effective local exhaust ventilation on cooking fumes of seasoned meats
BKESS, 1998Co-Authors: Byeong Kyu Lee, Michael J. EllenbeckerAbstract:This study identified the fumes produced from the cooking of the seasoned meats containing various condiments such as garlic, onion, pepper, soy sauce, and sesame oil. Concentrations, at the breathing zone of the cook, of volatile organic compounds (VOCs) and aldehydes included in the cooking fumes of seasoned meats were identified. Many chloro-and fluoro-aliphatic hydrocarbons, aromatic hydrocarbons, ketones, and aldehydes, which could be carcinogen suspecting chemicals, were producing from the cooking fumes of the seasoned meats. This study also identified the ventilation efficiencies of the cooking fumes of the six exhaust ventilation systems, which were widely being used in the general apartments, houses, and small-food factories. For a comparison of the ventilation efficiencies of the systems, acetaldehyde was chosen as a marker pollutant and its concentrations at the breathing zone of the cook were identified. The laboratory fume Hood showed the best ventilation efficiency of the six ventilation systems studied, and then the lateral Hood ventilation and the down draft ventilation followed the laboratory fume Hood. Finally, this study identified that both a wall factor nearby pollutant sources and a distance factor between the Hood Face and pollutant sources should be also considered for an effective local exhaust ventilation system design.
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effective local exhaust ventilation on cooking fumes of seasoned meats
Journal of Environmental Sciences-china, 1993Co-Authors: Byeong Kyu Lee, Michael J. EllenbeckerAbstract:This study identified the fumes produced from the cooking of the seasoned meats containing various condiments such as garlic, onion, pepper, soy sauce, and sesame oil. Concentrations, at the breathing zone of the cook, of volatile organic compounds (VOCs) and aldehydes included in the cooking fumes of seasoned meats were identified. Many chloro- and fluoro-aliphatic hydrocarbons, aromatic hydrocarbons, ketones, and aldehydes, which could be carcinogen suspecting chemicals, were producing from the cooking fumes of the seasoned meats. This study also identified the ventilation efficiencies of the cooking fumes of the six exhaust ventilation systems, which were widely being used in the general apartments, houses, and small-food factories. For a comparison of the ventilation efficiencies of the systems, acetaldehyde was chosen as a marker pollutant and its concentrations at the breathing zone of the cook were identified. The laboratory fume Hood showed the best ventilation efficiency of the six ventilation systems studied, and then the lateral Hood ventilation and the down draft ventilation followed the laboratory fume Hood. Finally, this study identified that both a wall factor nearby pollutant sources and a distance factor between the Hood Face and pollutant sources should be also considered for an effective local exhaust ventilation system design.
Rong Fung Huang - One of the best experts on this subject based on the ideXlab platform.
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effects of boundary layer separation controllers on a desktop fume Hood
Journal of Occupational and Environmental Hygiene, 2016Co-Authors: Rong Fung Huang, Jiakun Chen, Shuofu HungAbstract:ABSTRACTA desktop fume Hood installed with an innovative design of flow boundary-layer separation controllers on the leading edges of the side plates, work surFace, and corners was developed and characterized for its flow and containment leakage characteristics. The geometric features of the developed desktop fume Hood included a rearward offset suction slot, two side plates, two side-plate boundary-layer separation controllers on the leading edges of the side plates, a slanted surFace on the leading edge of the work surFace, and two small triangular plates on the upper left and right corners of the Hood Face. The flow characteristics were examined using the laser-assisted smoke flow visualization technique. The containment leakages were measured by the tracer gas (sulphur hexafluoride) detection method on the Hood Face plane with a mannequin installed in front of the Hood. The results of flow visualization showed that the smoke dispersions induced by the boundary-layer separations on the leading edges of...
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Effects of boundary-layer separation controllers on a desktop fume Hood
Journal of occupational and environmental hygiene, 2016Co-Authors: Rong Fung Huang, Jiakun Chen, Ching Min Hsu, Shuofu HungAbstract:A desktop fume Hood installed with an innovative design of flow boundary-layer separation controllers on the leading edges of the side plates, work surFace, and corners was developed and characterized for its flow and containment leakage characteristics. The geometric features of the developed desktop fume Hood included a rearward offset suction slot, two side plates, two side-plate boundary-layer separation controllers on the leading edges of the side plates, a slanted surFace on the leading edge of the work surFace, and two small triangular plates on the upper left and right corners of the Hood Face. The flow characteristics were examined using the laser-assisted smoke flow visualization technique. The containment leakages were measured by the tracer gas (sulphur hexafluoride) detection method on the Hood Face plane with a mannequin installed in front of the Hood. The results of flow visualization showed that the smoke dispersions induced by the boundary-layer separations on the leading edges of the side plates and work surFace, as well as the three-dimensional complex flows on the upper-left and -right corners of the Hood Face, were effectively alleviated by the boundary-layer separation controllers. The results of the tracer gas detection method with a mannequin standing in front of the Hood showed that the leakage levels were negligibly small (≤0.003 ppm) at low Face velocities (≥0.19 m/s).
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Flow characteristics and robustness of an inclined quad-vortex range Hood.
Industrial health, 2014Co-Authors: Jiakun Chen, Rong Fung HuangAbstract:A novel design of range Hood, which was termed the inclined quad-vortex (IQV) range Hood, was examined for its flow and containment leakage characteristics under the influence of a plate sweeping across the Hood Face. A flow visualization technique was used to unveil the flow behavior. Three characteristic flow modes were observed: convex, straight, and concave modes. A tracer gas detection method using sulfur hexafluoride (SF 6) was employed to measure the con- tainment leakage levels. The results were compared with the test data reported previously in the literature for a conventional range Hood and an inclined air curtain (IAC) range Hood. The leakage SF6 concentration of the IQV range Hood under the influence of the plate sweeping was 0.039 ppm at a suction flow rate of 9.4 m 3 /min. The leakage concentration of the conventional range Hood was 0.768 ppm at a suction flow rate of 15.0 m 3 /min. For the IAC range Hood, the leakage concentration was 0.326 ppm at a suction flow rate of 10.9 m 3 /min. The IQV range Hood presented a significantly lower leakage level at a smaller suction flow rate than the conventional and IAC range Hoods due to its aerodynamic design for flow behavior.
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Flow and Leakage Characteristics of a Sashless Inclined Air-Curtain (sIAC) Fume Hood Containing Tall Pollutant-Generation Tanks
Journal of Occupational and Environmental Hygiene, 2013Co-Authors: Jiakun Chen, Rong Fung Huang, Wei Lun HungAbstract:In many fume Hood applications, pollutant-generation devices are tall. Human operators of a fume Hood must stand close to the front of the Hood and lift up their hands to reach the top opening of the tall tank. In this situation, it is inconvenient to access the conventional Hood because the sash acts as a barrier. Also, the bluff-body wake in front of the operator's chest causes a problem. By using laser-assisted smoke flow visualization and tracer-gas test methods, the present study examines a sashless inclined air-curtain (sIAC) fume Hood for tall pollutant-generation tanks, with a mannequin standing in front of the Hood Face. The configuration of the sIAC fume Hood, which had the important element of a backward-inclined push-pull air curtain, was different from conventional configurations. Depending on suction velocity, the backward-inclined air curtain had three characteristic modes: straight, concave, and attachment. A large recirculation bubble covering the area—from the Hood ceiling to the work su...
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Flow and Containment Characteristics of a Sash-less, Variable-Height Inclined Air-Curtain Fume Hood
Annals of Occupational Hygiene, 2013Co-Authors: Rong Fung Huang, Jiakun Chen, Wei Lun HungAbstract:To increase containment efficiency and reduce energy consumption, a sash-less, variable-height inclined air-curtain fume Hood (sIAC Hood) was developed and tested by a laser-assisted flow visualization technique and tracer-gas detection method. This novel design requires neither sash nor baffle. The sIAC Hood employed the inclined push-pull air-curtain technique and two deflection plates installed on the side walls of the Hood to induce a tetra-vortex flow structure. The results of flow visualization showed that the slot for suction flow, offset from the slot for the up-blowing jet, caused the air curtain to incline towards the rear wall, thus enhancing the robustness of the tetra-vortex flow structure. Such a flow structure could reduce the influence of draught and human walk-by across the Hood Face. The containment around the central area of the Hood was isolated by the inclined push-pull air curtain. The pollutants carried by the reverse flow induced by the flow separation were guided by the deflection plates from the side walls towards the rear, thus contributing to the formation of the tetra-vortex flow structure. The up/down movable ceiling positioned the suction slot close to the device's pollutant emission opening, but left room (less than 50 cm) for unrestricted hand movement. Testing was carried out based on the methodology described in EN14175. The results of a static test showed that small Face velocities of 0.25 and 0.16 m s(-1) were enough to obtain nearly null leakage levels for low and tall pollutant sources. The results of a traversing plate test showed that the Face velocity, 0.32 m s(-1), would cause negligibly small leakage levels. The sIAC Hood could obtain significantly higher containment efficiency than a conventional Hood by operating at a Face velocity significantly lower than that of conventional Hoods.
Byeong Kyu Lee - One of the best experts on this subject based on the ideXlab platform.
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articles effective local exhaust ventilation on cooking fumes of seasoned meats
BKESS, 1998Co-Authors: Byeong Kyu Lee, Michael J. EllenbeckerAbstract:This study identified the fumes produced from the cooking of the seasoned meats containing various condiments such as garlic, onion, pepper, soy sauce, and sesame oil. Concentrations, at the breathing zone of the cook, of volatile organic compounds (VOCs) and aldehydes included in the cooking fumes of seasoned meats were identified. Many chloro-and fluoro-aliphatic hydrocarbons, aromatic hydrocarbons, ketones, and aldehydes, which could be carcinogen suspecting chemicals, were producing from the cooking fumes of the seasoned meats. This study also identified the ventilation efficiencies of the cooking fumes of the six exhaust ventilation systems, which were widely being used in the general apartments, houses, and small-food factories. For a comparison of the ventilation efficiencies of the systems, acetaldehyde was chosen as a marker pollutant and its concentrations at the breathing zone of the cook were identified. The laboratory fume Hood showed the best ventilation efficiency of the six ventilation systems studied, and then the lateral Hood ventilation and the down draft ventilation followed the laboratory fume Hood. Finally, this study identified that both a wall factor nearby pollutant sources and a distance factor between the Hood Face and pollutant sources should be also considered for an effective local exhaust ventilation system design.
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effective local exhaust ventilation on cooking fumes of seasoned meats
Journal of Environmental Sciences-china, 1993Co-Authors: Byeong Kyu Lee, Michael J. EllenbeckerAbstract:This study identified the fumes produced from the cooking of the seasoned meats containing various condiments such as garlic, onion, pepper, soy sauce, and sesame oil. Concentrations, at the breathing zone of the cook, of volatile organic compounds (VOCs) and aldehydes included in the cooking fumes of seasoned meats were identified. Many chloro- and fluoro-aliphatic hydrocarbons, aromatic hydrocarbons, ketones, and aldehydes, which could be carcinogen suspecting chemicals, were producing from the cooking fumes of the seasoned meats. This study also identified the ventilation efficiencies of the cooking fumes of the six exhaust ventilation systems, which were widely being used in the general apartments, houses, and small-food factories. For a comparison of the ventilation efficiencies of the systems, acetaldehyde was chosen as a marker pollutant and its concentrations at the breathing zone of the cook were identified. The laboratory fume Hood showed the best ventilation efficiency of the six ventilation systems studied, and then the lateral Hood ventilation and the down draft ventilation followed the laboratory fume Hood. Finally, this study identified that both a wall factor nearby pollutant sources and a distance factor between the Hood Face and pollutant sources should be also considered for an effective local exhaust ventilation system design.
Jiakun Chen - One of the best experts on this subject based on the ideXlab platform.
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effects of boundary layer separation controllers on a desktop fume Hood
Journal of Occupational and Environmental Hygiene, 2016Co-Authors: Rong Fung Huang, Jiakun Chen, Shuofu HungAbstract:ABSTRACTA desktop fume Hood installed with an innovative design of flow boundary-layer separation controllers on the leading edges of the side plates, work surFace, and corners was developed and characterized for its flow and containment leakage characteristics. The geometric features of the developed desktop fume Hood included a rearward offset suction slot, two side plates, two side-plate boundary-layer separation controllers on the leading edges of the side plates, a slanted surFace on the leading edge of the work surFace, and two small triangular plates on the upper left and right corners of the Hood Face. The flow characteristics were examined using the laser-assisted smoke flow visualization technique. The containment leakages were measured by the tracer gas (sulphur hexafluoride) detection method on the Hood Face plane with a mannequin installed in front of the Hood. The results of flow visualization showed that the smoke dispersions induced by the boundary-layer separations on the leading edges of...
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Effects of boundary-layer separation controllers on a desktop fume Hood
Journal of occupational and environmental hygiene, 2016Co-Authors: Rong Fung Huang, Jiakun Chen, Ching Min Hsu, Shuofu HungAbstract:A desktop fume Hood installed with an innovative design of flow boundary-layer separation controllers on the leading edges of the side plates, work surFace, and corners was developed and characterized for its flow and containment leakage characteristics. The geometric features of the developed desktop fume Hood included a rearward offset suction slot, two side plates, two side-plate boundary-layer separation controllers on the leading edges of the side plates, a slanted surFace on the leading edge of the work surFace, and two small triangular plates on the upper left and right corners of the Hood Face. The flow characteristics were examined using the laser-assisted smoke flow visualization technique. The containment leakages were measured by the tracer gas (sulphur hexafluoride) detection method on the Hood Face plane with a mannequin installed in front of the Hood. The results of flow visualization showed that the smoke dispersions induced by the boundary-layer separations on the leading edges of the side plates and work surFace, as well as the three-dimensional complex flows on the upper-left and -right corners of the Hood Face, were effectively alleviated by the boundary-layer separation controllers. The results of the tracer gas detection method with a mannequin standing in front of the Hood showed that the leakage levels were negligibly small (≤0.003 ppm) at low Face velocities (≥0.19 m/s).
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Flow characteristics and robustness of an inclined quad-vortex range Hood.
Industrial health, 2014Co-Authors: Jiakun Chen, Rong Fung HuangAbstract:A novel design of range Hood, which was termed the inclined quad-vortex (IQV) range Hood, was examined for its flow and containment leakage characteristics under the influence of a plate sweeping across the Hood Face. A flow visualization technique was used to unveil the flow behavior. Three characteristic flow modes were observed: convex, straight, and concave modes. A tracer gas detection method using sulfur hexafluoride (SF 6) was employed to measure the con- tainment leakage levels. The results were compared with the test data reported previously in the literature for a conventional range Hood and an inclined air curtain (IAC) range Hood. The leakage SF6 concentration of the IQV range Hood under the influence of the plate sweeping was 0.039 ppm at a suction flow rate of 9.4 m 3 /min. The leakage concentration of the conventional range Hood was 0.768 ppm at a suction flow rate of 15.0 m 3 /min. For the IAC range Hood, the leakage concentration was 0.326 ppm at a suction flow rate of 10.9 m 3 /min. The IQV range Hood presented a significantly lower leakage level at a smaller suction flow rate than the conventional and IAC range Hoods due to its aerodynamic design for flow behavior.
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Flow and Leakage Characteristics of a Sashless Inclined Air-Curtain (sIAC) Fume Hood Containing Tall Pollutant-Generation Tanks
Journal of Occupational and Environmental Hygiene, 2013Co-Authors: Jiakun Chen, Rong Fung Huang, Wei Lun HungAbstract:In many fume Hood applications, pollutant-generation devices are tall. Human operators of a fume Hood must stand close to the front of the Hood and lift up their hands to reach the top opening of the tall tank. In this situation, it is inconvenient to access the conventional Hood because the sash acts as a barrier. Also, the bluff-body wake in front of the operator's chest causes a problem. By using laser-assisted smoke flow visualization and tracer-gas test methods, the present study examines a sashless inclined air-curtain (sIAC) fume Hood for tall pollutant-generation tanks, with a mannequin standing in front of the Hood Face. The configuration of the sIAC fume Hood, which had the important element of a backward-inclined push-pull air curtain, was different from conventional configurations. Depending on suction velocity, the backward-inclined air curtain had three characteristic modes: straight, concave, and attachment. A large recirculation bubble covering the area—from the Hood ceiling to the work su...
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Flow and Containment Characteristics of a Sash-less, Variable-Height Inclined Air-Curtain Fume Hood
Annals of Occupational Hygiene, 2013Co-Authors: Rong Fung Huang, Jiakun Chen, Wei Lun HungAbstract:To increase containment efficiency and reduce energy consumption, a sash-less, variable-height inclined air-curtain fume Hood (sIAC Hood) was developed and tested by a laser-assisted flow visualization technique and tracer-gas detection method. This novel design requires neither sash nor baffle. The sIAC Hood employed the inclined push-pull air-curtain technique and two deflection plates installed on the side walls of the Hood to induce a tetra-vortex flow structure. The results of flow visualization showed that the slot for suction flow, offset from the slot for the up-blowing jet, caused the air curtain to incline towards the rear wall, thus enhancing the robustness of the tetra-vortex flow structure. Such a flow structure could reduce the influence of draught and human walk-by across the Hood Face. The containment around the central area of the Hood was isolated by the inclined push-pull air curtain. The pollutants carried by the reverse flow induced by the flow separation were guided by the deflection plates from the side walls towards the rear, thus contributing to the formation of the tetra-vortex flow structure. The up/down movable ceiling positioned the suction slot close to the device's pollutant emission opening, but left room (less than 50 cm) for unrestricted hand movement. Testing was carried out based on the methodology described in EN14175. The results of a static test showed that small Face velocities of 0.25 and 0.16 m s(-1) were enough to obtain nearly null leakage levels for low and tall pollutant sources. The results of a traversing plate test showed that the Face velocity, 0.32 m s(-1), would cause negligibly small leakage levels. The sIAC Hood could obtain significantly higher containment efficiency than a conventional Hood by operating at a Face velocity significantly lower than that of conventional Hoods.
Zhou Shulin - One of the best experts on this subject based on the ideXlab platform.
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Center-Line Velocity Change Regime in a Parallel-Flow Square Exhaust Hood.
International journal of environmental research and public health, 2020Co-Authors: Chen Jianwu, Yang Bin, Chen Zhenfang, Longzhe Jin, Yanqiu Sun, Zhou ShulinAbstract:A parallel-flow exhaust Hood is an effective ventilation device to control dust and toxic pollutants and protect the occupational health of workers, whether it is used alone or combined with a uniform air supply Hood in a push-pull ventilation system. Some scholars have studied the outside air flow characteristics of the conventional exhaust Hood with non-uniform air speed at the Hood Face, but the law of velocity variation outside the parallel-flow exhaust Hood is not clear at present. Therefore, this paper uses the dimensionless method to study the center-line velocity change regime in a parallel-flow square exhaust Hood based on simulation and experimental data. The results show that the dimensionless center-line velocity has a good change law with the characteristic length of exhaust Hood in a parallel-flow square exhaust Hood, which can eliminate the influence of Hood Face velocity and the Hood size on the velocity change regime; and the experimental data is basically consistent with the calculated data, which shows that the regression equation method is reliable.
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The Influence on the Limit Flow Ratio Caused by the Change of the Area of the Exhaust Hood Face in the Design of Push–Pull Ventilation
Lecture Notes in Electrical Engineering, 2019Co-Authors: Zhou Shulin, Yang Bin, Zhang HuijunAbstract:This study is to investigate whether the change of the exhaust Hood area has an effect on the limiting flow ratio KL in an push–pull ventilation device, especially when the Face area of the supply Hood is larger than the exhaust Hood. This research is based on experiment. Set up a push–pull ventilation device, change the area of the exhaust Hood Face under the condition of maintaining other factors unchanged. Determine the minimum exhaust volume which completely drains the given air supply without overflow by the tracer method, and the KL could be deduced. The experimental results show that under the above experimental conditions, the change of the exhaust Hood area will cause a change on the limiting flow ratio KL, and the larger the gap between the supply and exhaust Hood area, the greater the KL value will be. Change the distance between the push and pull Hood Face, repeat the above experiments, it is verified that the conclusions above are still valid when the distance changes.