Experimental Study on Discharge Coefficients of Windward Window in Buildings with Wind-Driven Cross Ventilation

2014 ◽  
Vol 1008-1009 ◽  
pp. 1061-1067
Author(s):  
Qiao Ning Wang ◽  
Yan Ling Guan ◽  
Qi Hai Liao
Keyword(s):  
Flow Rate ◽  
Natural Ventilation ◽  
Discharge Coefficient ◽  
Static Pressure ◽  
Flow Rates ◽  
Discharge Coefficients ◽  
Window Opening ◽  
Static Pressure Difference ◽  
Window Area ◽  
The Impact

Focus on the prediction of flow rates in buildings under natural ventilation, the investigation conducted a series of model rooms with cross ventilation. The impact of window-wall ratios, windows configurations as well as corresponding flow rates was investigated. The object of this investigation is to analyze characteristics of windward window opening discharge coefficient by measuring static pressure difference and the flow rate through windows. The conclusion are as follows: For large openings, the discharge coefficient of windward window opening increases as the window-wall ratio grows up; With windward window-wall ratio of 44.4% and 11.1%, the discharge coefficient of windward openings is almost irrelevant to flow rate and less affected by leeward window area; However, with windward window-wall ratio of 2.78%, the discharge coefficient increases slightly as flow rate rises, and the larger the area of leeward opening is, the smaller the discharge coefficient of windward opening becomes.

Experimental Study of Ingestion in the Rotor-Stator Disk Cavity of a Subscale Axial Turbine Stage

2014 ◽  
Author(s):  
J. Balasubramanian ◽  
P. S. Pathak ◽  
J. K. Thiagarajan ◽  
P. Singh ◽  
R. P. Roy ◽  
...  
Keyword(s):  
Flow Field ◽  
Flow Rate ◽  
Discharge Coefficient ◽  
Computational Effort ◽  
Radial Clearance ◽  
Turbine Stage ◽  
Flow Rates ◽  
Axial Turbine ◽  
Discharge Coefficients ◽  
Purge Flow

While it is widely recognized that ingestion of hot gas from the main annulus of axial gas turbine stages into rotor-stator disk cavities depend strongly on the unsteadiness of the prevailing flow field, the large computational effort needed to simulate the flow field renders its use in the design of turbine internal air system and seals difficult. As an alternative, considerable effort has been devoted in recent years to develop simple orifice models of disk cavity rim seals based on time-averaged flow information; these models contain empirical discharge coefficients for ingestion into and egress from the cavities. The present experimental work in a subscale axial turbine stage reports a simple orifice model of an axially-overlapping radial-clearance seal at the disk cavity rim and values of the discharge coefficients over a range of purge flow rate supplied to the cavity. In the experiments, the ingestion process was dominated by the main gas annulus flow. Time-averaged static pressure distribution was measured in the main annulus and in the disk cavity; the driving force for ingestion and egress was taken to be the pressure differential between the main annulus and the rim cavity at prescribed locations. Time-averaged ingestion was measured using the tracer gas technique; the pressure and ingestion data were combined to obtain the ingestion and egress discharge coefficients at several purge flow rates. The location on the vane platform 1mm upstream of its lip represented the main gas annulus pressure in the calculation of discharge coefficients. In the rim cavity, two locations on the stator, one in the ‘seal region’ and the other slightly inward radially, were prescribed to represent the rim cavity pressure as well as the sealing effectiveness. Two corresponding sets of ingestion and egress discharge coefficients are reported for the various purge flow rates. The ingestion discharge coefficient obtained using the seal region location in the rim cavity decreased as the purge flow rate increased; the corresponding egress discharge coefficient increased with purge flow rate. For the rim cavity location slightly inward radially from the seal region, the egress discharge coefficient maintained the same trend; however, the ingestion discharge coefficient decreased only slightly as the purge flow rate increased. It is suggested that the seal region location in the rim cavity is the more appropriate location in calculating the rim seal discharge coefficients. The ratio of ingestion to egress discharge coefficients exhibited considerable variation with purge flow rate.

Experimental Study of the Flow in the Suction Pipe of a Centrifugal Pump at Partial Flow Rates in Unsteady Conditions

1999 ◽  
Vol 121 (3) ◽  
pp. 291-295 ◽  
Author(s):  
S. Bolpaire ◽  
J. P. Barrand
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Static Pressure ◽  
Pressure Measurements ◽  
Flow Rates ◽  
Suction Pipe ◽  
Start Up ◽  
Test Loop ◽  
Fast Start ◽  
Operational Range

The operational range and the performances of pumps are limited by the occurrence of backflow and prerotation in the suction pipe as the flow rate is reduced. This paper presents the study of static pressure measurements and visualizations in the suction pipe, near the inlet of a centrifugal pump, at partial flow rates, in steady conditions, and during a fast start-up of the pump. The tests were carried out in water on the DERAP© test loop of the ENSAM Lille laboratory. Standard methods allowed to determine the recirculation critical flow rate. A visualization method showed that the axial extent of the recirculation and the prerotation with the flow rate is considerably reduced during a fast start-up compared to steady conditions.

Aerodynamic Loss Characteristics of a Turbine Blade With Trailing Edge Coolant Ejection: Part 1—Effect of Cut-Back Length, Spanwise Rib Spacing, Free-Stream Reynolds Number, and Chordwise Rib Length on Discharge Coefficients

2000 ◽  
Vol 123 (2) ◽  
pp. 238-248 ◽  
Author(s):  
Oguz Uzol ◽  
Cengiz Camci ◽  
Boris Glezer
Keyword(s):  
Reynolds Number ◽  
Mass Flow Rate ◽  
Flow Rate ◽  
Discharge Coefficient ◽  
Free Stream ◽  
Cooling System ◽  
Trailing Edge ◽  
Discharge Coefficients ◽  
Reynolds Number Dependency ◽  
Spanwise Rib

The internal fluid mechanics losses generated between the blade plenum chamber and a reference point located just downstream of the trailing edge are investigated for a turbine blade trailing edge cooling system. The discharge coefficient Cd is presented as a function of the free-stream Reynolds number, cut-back length, spanwise rib spacing, and chordwise rib length. The results are presented in a wide range of coolant to free-stream mass flow rate ratios. The losses from the cooling system show strong free-stream Reynolds number dependency, especially at low ejection rates, when they are correlated against the coolant to free-stream pressure ratio. However, when Cd is correlated against a coolant to free-stream mass flow rate ratio, the Reynolds number dependency is eliminated. The current data clearly show that internal viscous losses due to varying rib lengths do not differ significantly. The interaction of the external wall jet in the cutback region with the free-stream fluid is also a strong contributor to the losses. Since the discharge coefficients do not have Reynolds number dependency at high ejection rates, Cd experiments can be performed at a low free-stream Reynolds number. Running a discharge coefficient experiment at low Reynolds number (or even in still air) will sufficiently define the high blowing rate portion of the curve. This approach is extremely time efficient and economical in finding the worst possible Cd value for a given trailing edge coolant system.

Flow Distribution and Pressure Drop in Steady Airflow Through a Selective Laser Sintered Human Tracheobronchial Airway Model

2003 ◽  
Author(s):  
Kah-Hoe Tan ◽  
Ramkumar N. Parthasarathy ◽  
M. Cengiz Altan ◽  
David L. Johnson ◽  
R. E. Clinkenbeard
Keyword(s):  
Pressure Drop ◽  
Static Pressure ◽  
Flow Distribution ◽  
Reynolds Numbers ◽  
Flow Rates ◽  
Physiological Flow ◽  
Static Pressure Difference ◽  
The Mean ◽  
The Relationship ◽  
Airway Model

The flow distribution and pressure drop of steady airflow in the human central airways were studied experimentally using an anatomically correct, selective laser sintered (SLS) human tracheobronchial airway model. Measurements were made for tracheal flow rates ranging from 0.1 to 2.67 liters per second, which correspond to normal physiological flow ranges. The mean air velocities at the exit orifices of the airway model were detected by means of a pitot static tube connected to a pressure transducer. The flow rates, the average velocities, and the Reynolds numbers in each branch of the airway model were then computed. In addition, the static pressure difference between the trachea and the airway exits was measured. The experimental measurements were used to determine the relationship between pressure drop and flow rate. The ratio of inlet to total exit area of the model was identified as a significant factor that influenced the pressure drop. The results obtained in the present study will be particularly useful for validating computational studies.

Large-Scale Testing to Validate the Influence of External Crossflow on the Discharge Coefficients of Film Cooling Holes

2000 ◽  
Vol 123 (3) ◽  
pp. 593-600 ◽  
Author(s):  
D. A. Rowbury ◽  
M. L. G. Oldfield ◽  
G. D. Lock
Keyword(s):  
Film Cooling ◽  
Stream Flow ◽  
Large Scale ◽  
Discharge Coefficient ◽  
Static Pressure ◽  
Free Stream ◽  
Discharge Coefficients ◽  
Large Scale Testing ◽  
Cooling Hole ◽  
Film Cooling Holes

This paper discusses large-scale, low-speed experiments that explain unexpected flow-interaction phenomena witnessed during annular cascade studies into the influence of external crossflow on film cooling hole discharge coefficients. More specifically, the experiments throw light on the crossover phenomenon, where the presence of the external crossflow can, under certain circumstances, increase the discharge coefficient. This is contrary to most situations, where the external flow results in a decrease in discharge coefficient. The large-scale testing reported helps to explain this phenomenon through an increased understanding of the interaction between the emerging coolant jet and the free-stream flow. The crossover phenomenon came to light during an investigation into the influence of external crossflow on the discharge coefficients of nozzle guide vane film cooling holes. These experiments were performed in the Cold Heat Transfer Tunnel (CHTT), an annular blowdown cascade of film cooled vanes that models the three-dimensional external flow patterns found in modern aero-engines. (Rowbury et al., 1997, 1998). The variation in static pressure around the exit of film cooling holes under different flow conditions was investigated in the large-scale tests. The study centered on three holes whose geometries were based on those found in the leading edge region of the CHTT vanes, as the crossover phenomenon was witnessed for these rows during the initial testing. The experiments were carried out in a low-speed wind tunnel, with the tunnel free-stream flow velocity set to match the free-stream Reynolds number (based on the local radius of curvature) and the “coolant” flow velocity set to replicate the engine coolant-to-free-stream momentum flux ratio. It was found that the apparent enhancement of film cooling hole discharge coefficients with external crossflow was caused by a reduction in the static pressure around the hole exit, associated with the local acceleration of the free-stream around the emerging coolant jet. When these measured static pressures (rather than the free-stream static pressure) were used to calculate the discharge coefficient, the crossover effect was absent. The improved understanding of the crossover phenomenon and coolant-to-free-stream interactions that has been gained will be valuable in aiding the formulation of predictive discharge coefficient schemes.

Effect of Formula Type and Preparation on International Dysphagia Diet Standardisation Initiative Thickness Level and Milk Flow Rates From Bottle Teats

2021 ◽  
Vol 30 (1) ◽  
pp. 260-265
Author(s):  
Britt F. Pados ◽  
Victoria Feaster
Keyword(s):  
Gastroesophageal Reflux ◽  
Infant Formula ◽  
Flow Rate ◽  
Infant Formulas ◽  
Testing Methods ◽  
Flow Rates ◽  
Milk Flow ◽  
Thin Liquids ◽  
The Impact ◽  
Formula Type

Purpose The purpose of this study was to evaluate the effect of infant formula type and preparation (i.e., ready-to-feed vs. powder) on International Dysphagia Diet Standardisation Initiative (IDDSI) thickness level and milk flow rates from bottle teats/nipples. Method The ready-to-feed and powder formulations of the following products were tested for IDDSI thickness level, using IDDSI guidelines, and for milk flow rate, using established flow testing methods: Similac Advance, Similac For Spit-Up, Enfamil Infant, and Enfamil A.R. Analysis of variance was used to compare flow rates among formula types/preparations. Results Enfamil A.R. ready-to-feed was classified as IDDSI “slightly thick.” All other formula types/preparations were found to be IDDSI “thin” liquids. The standard infant formulas (Similac Advance and Enfamil Infant) had comparable flow rates to each other, regardless of preparation (ready-to-feed and powder). The gastroesophageal reflux–specific formulas (Similac For Spit-Up and Enfamil A.R.) had slower flow rates than the standard formulas; within this category, there were significant differences in flow rates between ready-to-feed and powder. Enfamil A.R. powder had the slowest flow rate, but was the most variable. Conclusion For infants with difficulty coordinating sucking, swallowing, and breathing, clinicians and parents should consider the impact that changes to infant formula type and preparation may have on the infant's ability to safely feed.

Assessment of the impact of water parameters on the flow rate of ceramic pot filters in a long-term experiment

2015 ◽  
Vol 15 (6) ◽  
pp. 1425-1432 ◽  
Author(s):  
C. Salvinelli ◽  
A. C. Elmore
Keyword(s):  
Flow Rate ◽  
Water Production ◽  
Premature Failure ◽  
Initial Flow ◽  
Flow Rates ◽  
Treated Water ◽  
Long Term Study ◽  
The Impact ◽  
The Relationship

Poor water quality is a major contributing factor to disease in developing countries. Silver-coated ceramic pot filters (CPFs) are a relatively common form of household water treatment system (HWTS) representing an effective and sustainable technology for poor communities. Water production seems to be the major limiting factor of the CPF's lifetime and sustainability since low flow rates do not produce an adequate daily volume of treated water. This paper describes a long-term study of CPF flow rates under controlled conditions using three different water sources. The relationship between water characteristics and flow rate was assessed with the intent of identifying the principal parameters that impact CPF water production. The study concluded that turbidity seems to be the principal indicator in determining CPF lifetime in terms of quantity of treated water. There is no evidence that biological activity also contributes to premature failure of CPFs and the data did not indicate that chemical precipitation is responsible for the filter clogging. Manufacturers commonly conduct initial flow rate tests using clear water as a measure of quality assurance. However, the relationship between initial flow rate and average flow rate during the lifetime of the CPF should be further studied.

scholarly journals Experimental study of in-situ W/O emulsification during the injection of MgSO4 and Na2CO3 solutions in a glass micromodel

2020 ◽  
Vol 75 ◽  
pp. 87
Author(s):  
Sepideh Palizdan ◽  
Hossein Doryani ◽  
Masoud Riazi ◽  
Mohammad Reza Malayeri
Keyword(s):  
Experimental Study ◽  
Flow Rate ◽  
Oil Recovery ◽  
Deionized Water ◽  
Water Flooding ◽  
Flow Rates ◽  
Glass Micromodel ◽  
The Impact ◽  
Emulsification Process

In-situ emulsification of injected brines of various types is gaining increased attention for the purpose of enhanced oil recovery. The present experimental study aims at evaluating the impact of injecting various solutions of Na2CO3 and MgSO4 at different flow rates resembling those in the reservoir and near wellbore using a glass micromodel with different permeability regions. Emulsification process was visualized through the injection of deionized water and different brines at different flow rates. The experimental results showed that the extent of emulsions produced in the vicinity of the micromodel exit was profoundly higher than those at the entrance of the micromodel. The injection of Na2CO3 brine after deionized water caused the impact of emulsification process more efficiently for attaining higher oil recovery than that for the MgSO4 brine. For instance, the injection of MgSO4 solution after water flooding increased oil recovery only up to 1%, while the equivalent figure for Na2CO3 was 28%. It was also found that lower flow rate of injection would cause the displacement front to be broadened since the injected fluid had more time to interact with the oil phase. Finally, lower injection flow rate reduced the viscous force of the displacing fluid which led to lesser occurrence of viscous fingering phenomenon.

scholarly journals GROWTH AND PROTEIN CONTENT OF Ulva prolifera MAINTAINED AT DIFFERENT FLOW RATES IN INTEGRATED AQUACULTURE SYSTEM

2017 ◽  
Vol 9 (2) ◽  
pp. 429-441
Author(s):  
Wastu Ayu Diamahesa ◽  
Toshiro Masumoto ◽  
Dedi Jusadi ◽  
Mia Setiawati
Keyword(s):  
Protein Content ◽  
Flow Rate ◽  
Ammonia Nitrogen ◽  
Ulva Prolifera ◽  
Average Weight ◽  
Flow Rates ◽  
Integrated Aquaculture ◽  
Aquaculture System ◽  
Total Ammonia ◽  
The Impact

Efforts to reduce the impact of waste improvement on degradation of water quality can be transferred by utilization of inorganic waste as a source of seaweed nutrition. This study aimed to determine the growth and protein content of Ulva prolifera maintained at different flow rates in integrated aquaculture system. 9 Yellowtail stocked with 5.095 g with an average weight of 566.11±81.51 g were kept in 540 L tank for 24 days, by water flowing at the rate of 10 L min-1. Water from the fish tank was distributed into the sediment tank and go to 6 Ulva tanks with the flow rate of 0.5, 1.0 and 1.5 L min-1. Test parameters measured were growth performance of Yellowtail, biomass of Ulva prolifera, protein content of Ulva prolifera, and total ammonia nitrogen. The measurement results showed that the biomass of fish increased to 5.408 g, then biomass of Ulva increased to 42 g, 156 g and 155 g for flow rate of 0.5 L, 1 L and 1.5 L min-1, respectively. The protein content of Ulva for all the treatments was the same (P> 0.05). A total of ammonia in the tank outlet of Ulva (0.0202 - 0.1137 mg N L-1) were smaller than those were in the inlet (0.0286 - 0.1394 mg N L-1).

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