Begell House Inc.
International Journal of Fluid Mechanics Research
FMR
2152-5102
45
1
2018
EFFECTS OF VISCOSITY ON TRANSIENT BEHAVIOR OF A LOW SPECIFIC SPEED CENTRIFUGAL PUMP IN STARTING AND STOPPING PERIODS
1-20
10.1615/InterJFluidMechRes.2017018920
Yu-Liang
Zhang
College of Mechanical Engineering, Quzhou University, 324000, Quzhou, China
Zu-Chao
Zhu
The Zhejiang Provincial Key Lab of Fluid Transmission Technology, Zhejiang Sci-Tech
University, 310018, Hangzhou, China
Wen-Guang
Li
Department of Fluid Machinery, Lanzhou University of Technology, 730050, Lanzhou, China
Jun-Jian
Xiao
College of Mechanical Engineering, Quzhou University, 324000, Quzhou, China
low specific speed
centrifugal pump
viscosity
starting process
stopping process
transient performance
Low specific speed centrifugal pumps have been extensively applied in petroleum, petro-chemical, and other industrial
sectors to transport liquids in a variety of viscosity. Their transient performance during starting and stopping processes can be important for their operational reliability; however, this performance has not been tackled under pumping highly viscous oils conditions so far. In the article, the transient turbulent flows in a low specific speed centrifugal pump are simulated with CFD code in starting and stopping periods for three liquids. The effects of viscosity on instant performance parameters, head-flow rate curves, instant internal flow variables, and flow structures in the impeller and volute are demonstrated. The parameter synchronization characteristic, hysteresis phenomenon in head-flow rate curves, and pump affinity law modification are addressed. It is turn out that a highly viscous liquid can respond to the pump speed change more quick than water, but is subject to a more significant overshoot in the shaft-power curve; thus, a liquid with higher viscosity than water potentially can reduce the operational reliability of a low specific speed centrifugal pump during the starting period.
NUMERICAL MODELING OF DAM-BREAK FLOW OVER ERODIBLE BED BY ROE SCHEME WITH AN ORIGINAL DISCRETIZATION OF SOURCE TERM
21-36
10.1615/InterJFluidMechRes.2018019183
Sanae
Jelti
Laboratoire LME, Département de Physique, Université Mohammed Premier, Oujda, Morocco
M.
Mezouari
Laboratoire LME, Département de Physique, Université Mohammed Premier, Oujda, Morocco
M.
Boulerhcha
Laboratoire LME, Département de Physique, Université Mohammed Premier, Oujda, Morocco
finite volume method
dam-break flow
sediment transport
erodible bed
Roe scheme
This work deals with the numerical modeling of dam-break flow over an erodible bed. The mathematical model is a combination of the shallow water, the transport diffusion, and the bed morphology change equations. The system is solved by the finite volume Roe scheme, associated with an original treatment of the source term. The results of several
tests are presented in order to verify and validate the performance of the model.
ROLE OF ADDITIVES AND ELEVATED TEMPERATURE ON RHEOLOGY OF WATER-BASED DRILLING FLUID: A REVIEW PAPER
37-49
10.1615/InterJFluidMechRes.2018018948
Yogita
Weikey
PhD scholar, National Institute of Technology, Raipur
Shobha Lata
Sinha
Mechanical Engineering Department, National Institute of Technology–Raipur (CG), India
492010
Satish Kumar
Dewangan
Department of Mechanical Engineering, National Institute of Technology, Raipur (CG), India
rheology
water-based drilling fluid
bentonite
high-temperature additives
nanocomposite
Water-based drilling fluids are very popular due to their hole-cleaning property, less cost, abundance, environment
friendliness, etc. Bentonite clay is used as a chief raw material to be added for the preparation of water-based drilling fluids. Rheology of the water-based drilling fluid can be easily altered using the favorable additives to contribute to better performance during drilling operation, although bentonite is a major ingredient of water-based drilling fluids for this purpose. Still, additional contribution of other additives in efficient functioning of the drilling fluid becomes very important for various situations. The present review paper discusses the effect of various additives in the water–bentonite suspensions, which is base suspension of the majority of water-based drilling fluid. Effects of natural polymer, synthetic polymer, nanocomposite, etc. on rheology of water–bentonite suspensions have been reviewed based on the past researches and recent advances made in this field. Considerations have also been given to study the behavior of
these additives at elevated temperatures.
DUFOUR–SORET AND THERMOPHORETIC EFFECTS ON MAGNETOHYDRODYNAMIC MIXED CONVECTION CASSON FLUID FLOW OVER A MOVING WEDGE AND NON-UNIFORM HEAT SOURCE/SINK
51-74
10.1615/InterJFluidMechRes.2018020450
Rakesh
Choudhary
Bhartiya Skill Development University Jaipur
Rakesh
Choudhary
Manipal University Jaipur, Jaipur, Rajasthan, India
Falkner–Skan flow
MHD
non-uniform heat source/sink
thermophoresis
Soret/Dufour effects
mass transfer
The present work examined the computational study of Dufour-Soret and thermophoresis effects of magnetohydrodynamic
(MHD) Casson fluid over a moving wedge with viscous dissipation, porous medium, and non-uniform heat
source. The impact of wedge angle parameter and thermal buoyancy parameter was also included in this study. A similar transformation is applied to convert the non-linear partial differential equations into ordinary partial differential equations. For solving these equations we have used Runge–Kutta fourth–fifth-order Fehlberg Method (RKF-45) with shooting technique. The skin friction coefficient, Nusselt number, and Sherwood number are also analyzed. The results of various parameters are shown through graphically and in tabular form.
INFLUENCE OF TEMPERATURE-DEPENDENT CONDUCTIVITY ON CONVECTIVE HEAT TRANSFER IN A VERTICAL DUCT
75-91
10.1615/InterJFluidMechRes.2018019672
Jawali C.
Umavathi
Department of Mathematics, Gulbarga University, Gulbarga-585 106, Karnataka, India
natural convection
variable conductivity
viscous dissipation
rectangular duct
numerical results
finite difference method
An analysis has been carried out to study the flow and heat characteristics of a Newtonian fluid in a vertical rectangular duct. One of the vertical walls of the duct is cooled to a constant temperature, while the other wall is heated to constant but different temperature. The thermal conductivity is assumed to vary as a linear function of temperature. The basic equations governing the flow and heat transfer are highly non-linear coupled partial differential equations. Numerical solution of the problem is obtained by using finite difference method of second-order accuracy. The effects of various physical parameters such as conductivity parameter BK (-1 ≤ BK ≤ 1.0), Grashof number Gr (1.0 ≤ Gr ≤ 25.0), Brinkman number Br (0.01 ≤ Br ≤ 2.0), and aspect ratio A(0.5 ≤ A ≤ 2.0), which determine the velocity and temperature contours, are shown pictorially. Results are also presented for the skin friction, volumetric flow rate, and heat transfer rate for representative values of different key parameters. It is found that the intensity of the velocity contours is dense in the lower half region of the duct for negative values of conductivity variation parameter and in the upper region of the duct for positive values of conductivity variation parameter. The 3D contours on temperature are concave for negative values of BK and convex for positive values of BK.