scholarly journals On the application of storage coefficient determination by quasi-steady-state flow

2005 ◽  
Vol 36 (1) ◽  
pp. 13-20 ◽  
Author(s):  
Mehmet E. Birpinar ◽  
Ayhan Gazioglu

A simple analytical method has been used for estimating the storage coefficient provided that transmissivity of the aquifer is known at the quasi-steady-state condition in confined or unconfined aquifers. The application of the method has been performed for unconfined and confined aquifer test data in Chaj Doab, Pakistan with observation wells and compared with conventional methods in the groundwater flow literature dealing with pumping tests. The results from the methodology presented in this paper conform well in practice with the results obtained from the traditional methods on the basis of order of magnitude.

1996 ◽  
Vol 27 (4) ◽  
pp. 247-254 ◽  
Author(s):  
Zekâi Şen

A simple, approximate but practical graphical method is proposed for estimating the storage coefficient independently from the transmissivity value, provided that quasi-steady state flow data are available from a pumping test. In the past, quasi-steady state flow distance-drawdown data have been used for the determination of transmissivity only. The method is applicable to confined and leaky aquifers. The application of the method has been performed for various aquifer test data available in the groundwater literature. The results are within the practical limits of approximation compared with the unsteady state flow solutions.


1987 ◽  
Vol 18 (2) ◽  
pp. 101-110 ◽  
Author(s):  
Zekâi Şen

A method has been proposed for determining a unique storage coefficient value for confined and unconfined aquifers tapped by a large diameter well. The prerequisites for the application of this method are estimation of the transmissivity value and the field measurements of well radius, pumping discharge and time-drawdown measurements at large times, or preferably at the steady or quasi-steady state flow conditions. The application of the method does not require any complicated mathematical procedure of the classical type curve matching procedures. It is recommended especially as a supplementary method to the existing techniques in determining the storage coefficient.


Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1834
Author(s):  
Yuxi Li ◽  
Wanglin Li ◽  
Jiapeng He ◽  
Xiaojiao Zhang ◽  
Xinyi Li

Infiltration and anti-filtration recharge-pumping wells (hereinafter, referred to as IAF recharge-pumping wells) can enable rain-flood flowing in rivers or channel recharge to aquifers, in flood periods, and pump groundwater to be utilized in non-flood periods. In this study, a round IAF recharge-pumping well and a square IAF recharge-pumping well were developed, the structure and characteristic were introduced, the calculation equations of single-well recharge quantity of IAF recharge-pumping wells, in unconfined aquifers were deduced, and the steady-state flow recharge test was conducted in the laboratory. The conclusions were as follows. The theoretical equation of the single-well recharge quantity was reasonable. Compared to existing anti-filtration recharge wells, the new IAF recharge-pumping well had stronger anti-deposit and anti-scour abilities and the single-well recharge quantity increased by 400%. Compared to the square IAF recharge-pumping well, the round IAF recharge-pumping well had a better inlet flow pattern and a larger single-well recharge quantity. With an increase in the test times, the single-well recharge quantity gradually decreased and tended to be stable. The existence of the pumping pipe had a little influence on the single-well recharge quantity.


Author(s):  
Zakaria N. Ibrahim

Piping systems transporting fluid between plant components are subjected to a variety of anticipated and/or postulated flow changes that disturb their steady state operations. These changes cause the fluid flow to accelerate and/or decelerate. However, consideration of fluid elasticity transforms these disturbances into weak and/or strong propagating sound waves, depending upon the abruptness level of the fluid state change. This generates dynamic forces on the pipe segments of the piping system. A simple concept for understanding the piping fluid transient phenomenon from its physical perspective is presented. The piping system consists of several pipe segments, each segment having a constant cross-sectional flow area. The pipe segment is further divided into a consecutive series of zones. Each zone comprises two or three sub-zones of quasi steady state flow. The sub-zones are separated by interface fronts at which the jump in fluid pressure and velocity occurs across them. These fronts propagate and clash with each other to create the next temporal set of sub-zones quasi steady state flow. This method is denoted in this paper as steady state flow fronts clashing ‘SSFFC’. Clashing between the incident, transmitted and/or reflected wave fronts within the zone is introduced. As a precursor to the second part of a two-part publication, the SSFFC is physically illustrated and mathematically formulated to establish the temporal fluid steady state contained within each sub-zone constituting the pipe segment. The developed formulations are comparable to those instituted by the conventional method of characteristics. The pipe segment generalized fluid flow transient forces based on SSFFC methodology are also formulated. In the concurrent publication that forms part two of this presentation [8], sample applications of SSFFC methodology are illustrated.


Author(s):  
Hadi Ramin ◽  
Easwaran N. Krishnan ◽  
Gurubalan Annadurai ◽  
Carey J. Simonson

Abstract A small-scale test facility is developed to determine the sensible effectiveness of a Fixed-Bed Regenerator (FBR) and the results are used to validate a numerical model. The numerical and experimental results for quasi-steady-state conditions are in a good agreement within the experimental uncertainty bounds. At quasi-steady-state condition, the outlet temperature of FBR varies with time but cyclically repeats itself; this is an important difference between FBR (regenerator) and recuperator heat exchangers. The outlet temperature of recuperator heat exchangers reaches a constant value during the steady-state operation. The quasi-steady-state temperature profile is used to determine the sensible effectiveness of FBRs. However, FBRs undergo several cycles to reach the quasi-steady-state condition. The prediction of the duration of the transient duration of FBR is important for performance testing that could save money and time. CSA (Canadian Standards Association) recommends operating FBR for at least one hour to achieve a quasi-steady-state condition. This paper addresses the heat transfer behavior of FBRs during their transient operation. The initial transient cycles depend on the cycle period of FBR, air flow rate and the thermal condition of the exchanger at the beginning of the test. The small-scale FBR test facility is used to study the transient behavior of FBRs and this is the main focus of this paper. The temperature profile during the transient condition of FBR is obtained and the results are compared with the numerical model. The effects of the mass flow rate of air and the cycle duration on the transient period of FBR are studied. The results show that FBR reaches a quasi-steady state operation in less than 30 minutes. The results will be useful for understanding the time required for performance testing, which will reduce the cost and time of each test.


2000 ◽  
Vol 646 ◽  
Author(s):  
Tohru Takahashi ◽  
Tadashi Hasegawa

ABSTRACTL12 modified titanium trialuminides have been prepared by replacing 9at.% of the aluminum in Al3Ti with chromium and/or iron. The materials were recrystallized into single phase polycrystals after isothermal forging resulting in an average grain diameter of about 40μm. Lattice parameter of the material containing 9 at.% chromium or 9 at.% iron, are 0.3959nm and 0.3939nm, respectively. The lattice parameters varied linearly with composition between these values for additions of both chromium and iron. Uniaxial compression tests were performed at temperatures ranging from 293K to 1300K. The yield strength is not sensitive to chemical composition within the range of compositions tested. Flow stress serrations of a few % were observed at temperatures around 600K, where intermittent drops in flow stress started immediately after yielding and continued to the end. These serrations were observed up to about 800K. At 900K and above the materials became fully deformable. Quasi steady state flow and strain softening were observed at 1200K and 1300K, respectively, due to dynamic recrystallization.


2002 ◽  
Vol 57 (13) ◽  
pp. 2475-2501 ◽  
Author(s):  
Mehrdad Hashemi ◽  
Halil I. Kavak ◽  
Theodore T. Tsotsis ◽  
Muhammad Sahimi

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