scholarly journals Measure-valued solutions and the phenomenon of blow-down in logarithmic diffusion

2009 ◽  
Vol 352 (1) ◽  
pp. 515-547 ◽  
Author(s):  
Juan Luis Vázquez
Keyword(s):  
Blow Down

THE LIQUID NITROGEN COOLED MAGNET FOR THE EINDHOVEN MHD BLOW DOWN FACILITY

1984 ◽  
Vol 45 (C1) ◽  
pp. C1-595-C1-598
Author(s):  
W. F.H. Merck ◽  
Th. Roman ◽  
J. Rauch ◽  
E. Violi ◽  
R. K. Maix
Keyword(s):  
Liquid Nitrogen ◽  
Blow Down

Blow-Down Valve Noise and Interactions With Downstream Orifice Plates

2003 ◽  
Author(s):  
Denis G. Karczub ◽  
Fred W. Catron ◽  
Allen C. Fagerlund
Keyword(s):  
Noise Exposure ◽  
Control Valve ◽  
Low Noise ◽  
Noise Levels ◽  
Exposure Limits ◽  
Blow Down ◽  
Gas Processing ◽  
The Impact ◽  
Acoustic Fatigue ◽  
Infrequent Event

In a blow-down situation as might occur at a natural gas processing facility, noise levels are very high and significantly exceed the noise levels one would normally associate with a control valve. As the blow-down operation is an infrequent event, this may be permissible but requires consideration of the duration of these high noise levels to ensure that occupational noise exposure limits and acoustic fatigue limits are not exceeded. Tests of noise levels due to an 8-inch control valve in a 12-inch pipeline under blow-down conditions are compared here with noise level predictions based on the IEC standard. Consideration is also given to the impact of placing an orifice plate downstream of the control valve as is often done to reduce pressure drop across the valve in the expectation that control valve noise levels will be reduced. Simple orifice plates often installed by plant operators to achieve this goal are shown to have an adverse impact, and it is shown that a multi-hole diffuser or low-noise control valve should instead be used.

Experimental Study of Two-Phase Flow Induced by Cavitation Through a Safety Relief Valve

2013 ◽  
Author(s):  
Jorge Pinho ◽  
Patrick Rambaud ◽  
Saïd Chabane
Keyword(s):  
Local Minimum ◽  
Two Phase Flow ◽  
Flow Characteristics ◽  
Control Valve ◽  
Recovery Factor ◽  
Phase Flow ◽  
Relief Valve ◽  
Two Phase ◽  
Blow Down ◽  
Choked Flow

The goal of this study is to understand the behavior of a safety relief valve in presence of a two-phase flow induced by cavitation, in which the mass flux tends to be reduced. Two distinct safety relief valves are tested: an API 2J3 type and a transparent model based on an API 1 1/2G3 type. Instead of using a spring, the design of both valves allows the adjustment of the disk at any desired lift. Tests are conducted with water at ambient temperature. Results show a similar influence of cavitation on the flow characteristics of both valves. The liquid pressure recovery factor FL, which is normally used to identify a choked flow condition in a control valve, is experimentally determined in a safety relief valve. The existence of a local minimum located at a height position L/D = 0.14 indicates in this position, a change on the flow characteristics of both valves. It is verified that the existence of a local minimum in the liquid recovery factor is related to the minimum cross section of the flow, which does not remain constant for every lift positions. Furthermore, it is remarked that in the case of the 2J3 safety valve, the blow down ring adjustment has significant influence on the location of the minimum cross sections of the flow.

Dissolved Organic Matter in Steam Assisted Gravity Drainage Boiler Blow-Down Water

2013 ◽  
Vol 27 (7) ◽  
pp. 3883-3890 ◽  
Author(s):  
Subhayan Guha Thakurta ◽  
Abhijit Maiti ◽  
David J. Pernitsky ◽  
Subir Bhattacharjee
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Gravity Drainage ◽  
Blow Down ◽  
Steam Assisted Gravity Drainage

On the performance of a cascade of turbine rotor tip section blading in wet steam Part 3: Wake traverses

1997 ◽  
Vol 211 (8) ◽  
pp. 639-648 ◽  
Author(s):  
F Bakhtar ◽  
H Mashmoushy ◽  
O C Jadayel
Keyword(s):  
Liquid Phase ◽  
Two Phase Flow ◽  
Turbine Rotor ◽  
Phase Flow ◽  
Wet Steam ◽  
Flow Conditions ◽  
Two Phase ◽  
Blow Down ◽  
The Third ◽  
Phase Mixture

During the course of expansion of steam in turbines the fluid first supercools and then nucleates to become a two-phase mixture. The liquid phase consists of a large number of extremely small droplets which are difficult to generate except by nucleation. To reproduce turbine two-phase flow conditions requires a supply of supercooled vapour which can be achieved under blow-down conditions by the equipment employed. This paper is the third of a set describing an investigation into the performance of a cascade of rotor tip section profiles in wet steam and presents the results of the wake traverses.

scholarly journals Evaluation of a pilot plant for removal of nitrate from groundwater using ion exchange and recycled regenerant

2017 ◽  
Vol 12 (3) ◽  
pp. 541-548
Author(s):  
Sheldon Tarre ◽  
Michael Beliavski ◽  
Michal Green
Keyword(s):  
Ion Exchange ◽  
Batch Reactor ◽  
Nitrate Removal ◽  
Bacterial Count ◽  
Water Volume ◽  
Foam Fractionation ◽  
Well Water ◽  
Combined System ◽  
Blow Down ◽  
Product Water

A combined system of ion exchange (IX) and advanced biophysical treatment of a recirculating regenerant was tested for nitrate removal from groundwater with minimal brine discharge and chloride addition to the product water. Using well water containing 21.5 ± 1.4 mg NO3−-N/L, optimal IX operation was found at a service cycle of 500 bed volumes (BV). Product water nitrate concentrations (7.4 ± 1.4 mg/L as N) met regulations while minimizing both Cl− addition to the treated water (1.03 meq Cl− added per meq NO3−-N removed) and waste brine production (0.2% of the water volume treated). The total organic carbon in the product water was slightly higher (1.5 ± 0.5 vs. 1.3 ± 0.4 mg/L) than the well water and before disinfection the bacterial count was 10–700 cfu/ml. Brine used to regenerate the IX columns was treated first in a sequential batch reactor (SBR) for biological denitrification followed by ozonation for polishing. The SBR was operated at 8 hour cycles and achieved complete nitrate removal. An ozone dose of 3 to 5 mg/L brine allowed for efficient recycling of the denitrified regenerant by removing suspended solids by foam fractionation. In spite of the low brine blow-down, DOC in the recycled regenerant brine after a year of continuous operation was maintained at relatively low levels of 61.0 ± 11.6 mg/L.

Upstream Film Cooling on the Contoured Endwall of a Transonic Turbine Vane in an Annular Cascade

2020 ◽  
Author(s):  
Daniel A. Salinas ◽  
Izhar Ullah ◽  
Lesley M. Wright ◽  
Je-Chin Han ◽  
John W. McClintic ◽  
...  
Keyword(s):  
Film Cooling ◽  
Density Ratio ◽  
Lateral Spread ◽  
Pressure Sensitive Paint ◽  
Blow Down ◽  
Film Cooling Effectiveness ◽  
Pressure Sensitive ◽  
Mainstream Flow ◽  
Additional Protection ◽  
Annular Cascade

Abstract The effects of mainstream flow velocity, density ratio (DR), and coolant-to-mainstream mass flow ratio (MFR) were investigated on a vane endwall in a transonic, annular cascade. A blow down facility consisting of five vanes was used. The film cooling effectiveness was measured using binary pressure sensitive paint (BPSP). The mainstream flow was set using isentropic exit Mach numbers of 0.7 and 0.9. The coolant-to-mainstream density ratio varied from 1.0 to 2.0. The coolant to mainstream MFR varied from 0.75% to 1.25%. The endwall was cooled by eighteen discrete holes located upstream of the vane passage to provide cooling to the upstream half of the endwall. Due to the curvature of the vane endwall, the upstream holes provided uniform coverage entering the endwall passage. The coverage was effective leading to the throat of the passage, where the downstream holes could provide additional protection. Increasing the coolant flowrate increased the effectiveness provided by the film cooling holes. Increasing the density of the coolant increases the effectiveness on the endwall while enhancing the lateral spread of the coolant. Finally, increasing the velocity of the mainstream while holding the MFR constant also yields increased protection on the endwall. Over the range of flow conditions considered in this study, the binary pressure sensitive paint proved to be a valuable tool for obtaining detailed pressure and film effectiveness distributions.

Characterization of the morning transition from downslope to upslope winds and its connection with the nocturnal inversion breakup at the foot of a gentle slope

2021 ◽  
Author(s):  
Sofia Farina ◽  
Dino Zardi ◽  
Silvana Di Sabatino ◽  
Mattia Marchio ◽  
Francesco Barbano
Keyword(s):  
Salt Lake ◽  
Vertical Direction ◽  
Blow Down ◽  
Physical Mechanisms ◽  
Morning Transition ◽  
Thermally Driven ◽  
Slope Wind ◽  
Slope Flow ◽  
Nocturnal Inversion

<p>Thermally driven winds observed in complex terrain are characterized by a daily cycle dominated by two main phases: a diurnal phase in which winds blow upslope (anabatic), and a nocturnal one in which they revert their direction and blow down slope (katabatic). This alternating pattern also implies two transition phases, following sunrise and sunset respectively. </p><p>Here we study the up-slope component of the slope wind with a focus on the morning transition based on from the MATERHORN experiment, performed in Salt Lake Desert (Utah) between Fall 2012 and Spring 2013. </p><p>The analysis develops along three main paths of investigation. The first one is the selection of the suitable conditions for the study of the diurnal component and the characterization of the morning transition. The second one focuses on the deep analysis of the erosion of the nocturnal inversion at the foot of the slope in order to investigate the physical mechanisms driving it. And the third one consists in the comparison between the experimental data and the results of an analytical model (Zardi and Serafin, 2015). The study of the morning transition in the selected case studies allowed its characterization in terms of the relation with the solar radiation cycle, in terms of its seasonality and in terms of its propagation along the slope and along the vertical direction. Most of the results of this investigation are related to the identification of the main mechanisms of erosion of the nocturnal inversion at the foot of the slope and to its role to the beginning of the transition itself. Finally, it is shown how the above model can fairly reproduce the cycle between anabatic and katabatic flow and their intensity.</p><p>Zardi, D. and S. Serafin, 2015: An analytic solution for daily-periodic thermally-driven slope flow. Quart. J. Roy. Meteor. Soc., 141, 1968–1974.</p>

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