
Archive issue  vol.2 No.4
1.
MASS TRANSFER EFFECTS ON UNSTEADY MIXED
CONVECTION FLOW WITH CHEMICAL REACTION
H.S. TAKHAR
School of Engineering, University of Manchester
Manchester, M13 9PL, UK
B.K. JHA
Department of Mathematics, Banaras Hindu University
Varanasi221 005, INDIA
The effect of chemical reaction on unsteady forced and freeconvection flow
past an infinite vertical plate has been analysed. Analytical expressions for
the velocity field, leading edge effects, and skinfriction have been obtained
by using the Laplace transform technique. The effects of K (chemical reaction
parameter), Sc (Schmidt number) and t (time parameter) on the velocity field,
leading edge, and skinfriction have been extensively discussed.

Key words: 
mixed convection flow, chemical reaction, Laplace transform, mass transfer, leading edge effect. 
TOP OF PAGE 
2.
COMBINED CONVECTION IN POWERLAW FLUIDS
ALONG A VERTICAL WEDGE EMBEDDED IN A POROUS MEDIUM
Rama Subba Reddy GORLA
Department of Mechanical Engineering
Cleveland State University, Cleveland
Ohio 44115, USA
Mahesh KUMARI
Department of Mathematics
Indian Institute of Science
Bangalore 560 012, INDIA
A nonsimilar boundary layer analysis is presented for the problem of
combined convection from a vertical wedge in a porous medium saturated with a
powerlaw type nonNewtonian fluid. The transformed conservation laws are solved
numerically for the case of variable surface heat flux conditions. Results for
the details of the velocity and temperature fields as well as the Nusselt number
have been presented. The viscosity index ranged from 0.5 to 1.5 and the wedge
angle parameter ranged from 0 to 1.

Key words: 
nonNewtonian fluids, combined convection, porous media, heat transfer. 
TOP OF PAGE 
3.
STUDY ON THE RHEOLOGICAL BEHAVIOR OF POLYMER
MELTS AND CONCENTRATED SOLUTIONS
M.S. SONG, J.C. YANG, C. ZHANG
Research Institute of Polymer Materials
Beijing University of Chemical Technology
Beijing 100029, P.R.CHINA
Based on a mutipleentanglement model, a new relation of linear viscoelastic
functions (the zero rate shear viscosity 'eta'_{0}, the zero extensional rate viscosity
'eta'_{ext}^{0}, the first normal stress coefficient 'psi'_{10}^{0} , and the terminal relaxation time 'tau')
to the molecular weight and its distribution for flexible chain polymer were
formulated. The dependence of scaling of exponent of entanglement networks in
the long entanglement spacing 'ypsilon' or 'ypsilon' for testing flexible chain polymers on the
primary molecular weight and the number of testing polymers was derived from the
two types relaxation mechanisms. A new method for determining the 'ypsilon' and 'ypsilon' for
mono and polydipersed polymer was proposed. It shows that when M_{n} = 3M_{e} to 6M_{e}, the
values of 'ypsilon' can range from 3.77 down to 3.33, their values are in a good
agreement with the experimental results for different molecular weight of
monoand polydispersed polymers and different polymer species. The dependence of
'eta'_{0}, 'psi'_{10}^{0}, 'eta'_{ext}^{0} and 'tau'_{T} on the weight average molecular weight and its distribution was
derived from the constrained multidimensional number of entanglements per
polymer chain and the primary molecular weight distribution function with the
statistical method.

Key words: 
rheological behavior, viscoelasticity, multidimensional topography of constraint, dependence of 'eta'_{0} on M_{w} / M_{n}. 
TOP OF PAGE 
4.
INFLUENCE OF HELICALCOILED WIRE
INSERTS IN TURBULENT PIPE FLOWS
Melda Ö.ÇARPINLIOGLU, Mustafa OZBEY
Gaziantep University Faculty of Engineering
Mechanical Engineering Department
Gaziantep 27310 TURKEY
An experimental investigation has been conducted on the influence of
helicalcoiled wires in turbulent pipe flows in the Reynolds number range of
30000 =< Re =< 90000. Helical coiled wires of varying diameter d, length L, pitch
p, number of coils n and helix angle a were used in the study. The dimensionless
insert parameters covered the ranges 13.33 =< D/d =< 26.66, 5 =< p/d =< 21.3, 50 =<
L/d =< 300, 4.7 =< n =< 30 with helix angles 66.6^{o} =< 'alpha' =< 79^{o}. The influence of inserts was
determined through the measurements of mean axial, tangential velocity profiles
and static pressure profiles in the flow field. Hydrodynamic performance of
inserts were expressed in terms of correlations between flow friction factor, f
and nondimensional insert parameters.

Key words: 
insert, friction factor, insert dimensions. 
TOP OF PAGE 
5.
TURBULENT FRICTION FACTOR FOR TWOPHASE:
AIR AND POWERLAW FLUID FLOWS THROUGH A HORIZONTAL TUBE
B.K. RAO
College of Engineering
Idaho State University, Pocatello, ID, 83209 USA
The fully developed twophase turbulent isothermal Fanning friction factors
for airpowerlaw fluid flows through a horizontal tube were measured
experimentally. The test fluids were aqueous solutions of Carbopol. Over the
range of the generalized Reynolds number (Re') from 10.000 to 100.000, the
homogeneous model was found to be accurate enough for engineering prediction of
turbulent friction factor for air and powerlaw fluid flows through horizontal
tubes.

Key words: 
twophase, turbulent, friction factor, powerlaw fluids. 
TOP OF PAGE 
6.
ATOMIC OSCILLATOR WITH SPINNING AND
ORBITING ELECTRON AS RADIATOR OF HEAT
Viktor PEKÁREK
Institute of Electrical Engineering, Academy of Sciences
of the Czech Republic
Dolejškova 5, 182 02 Prague 8, CZECH REPUBLIC
The subatomistic treatment of the theory of radiation allows the intrinsic
oscillation of the electron to be interpreted as the crucial mechanism
underlying the emission and absorption of heat. Considering the
threedimensional MaxwellBoltzmann energydistribution, the ordinary method of
statistics yields the mean energy per particle in the form ____ that is compatible
with the Planck radiation law. The theory defines the conditions for space
quantization of the orbital and intrinsic angular momenta of elementary
particles, transposing the probabilistic views of classical thermodynamics into
quantum mechanics of a single atom.

Key words: 
1D and 3D MaxwellBoltzmann energy distribution, mean energy, zeropoint energy, space quantization, orbital angular momentum, intrinsic angular momentum, electron, photon. 
TOP OF PAGE 
7.
NONLINEAR ANALYSIS OF FLEXIBLY SUPPORTED
FINITE TURBULENT FLOW OIL JOURNAL BEARINGS
A.K. CHATTOPADHYAY
Department of Mechanical Engineering
B.E. College (Deemed University), Howrah
West Bengal, INDIA
S. KARMAKAR
Research and Development Departments
W P I L Limited, Panihati
West Bengal, INDIA
A theoretical analysis is presented investigating the stability of a
symmetrical, rigid rotor on a flexibly supported journal bearing. Oilfilm flow
in the bearing is assumed to be turbulent and the dynamics of the system is
studied by calculating the components of fluid film force by solving the
generalized Reynolds equation modified to include the effect of turbulence and
using these in the nonlinear equation of motion of the journal and the bearing.
The modified Reynolds equation is solved for pressure distribution by using
finite difference method with S.O.R. scheme. The equations of motion are solved
by state space technique using the fourth order RungeKutta method as the tool
for solving the nonlinear equations. This gives the transient response of the
journalbearing system. The locus of the journal centre indicates whether the
system is stable, marginally stable or unstable. The results indicate that other
parameters e.g. aspect ratio, eccentricity ratio, mass parameter, stiffness and
damping parameters of the support system remaining fixed an increase in
turbulence results towards more stable orbit.

Key words: 
journal, bearing, finite, turbulent, stability. 
TOP OF PAGE 
8.
2D AND 3D COMPUTER MODELLING OF
EXPLOSIVE FORMATION OF PROJECTILES
K. JACH, M. MROCZKOWSKI, A. SARZYŃSKI, R. ŚWIERCZYŃSKI, J. TYL
Institute of Optoelectronics, Military University of Technology
Kaliskiego 2, 01489 Warsaw, POLAND
In the paper, equations of the motion of media completed by constitutive
relations rendering properties of materials have been presented. The
physicalmathematical model described in this paper contains a description of
elastic/viscoplastic properties of materials, considers their strength
characteristics and possibility of crack formation. Equations of the problem as
a result of their complexity, nonlinearity, multidimensionality are solved
numerically. In this case, the method of free particles has been applied in
numerical analysis. The results of exemplary 2D and 3D numerical solutions
illustrating processes of explosive formation of projectiles have been presented.
High degree of accuracy of the results of the computer simulations makes the
applied theoretical methods an important tool for the design of explosive
formation of projectiles (EFP).

Key words: 
explosive formation of projectiles (EFP), numerical modelling. 
TOP OF PAGE 
9. Brief note
A SIMPLIFIED CONCEPT OF IMPROVING A DIE
FILL IN FORGING OF BEVEL GEARS
Georgi Georgiev PETZOV, Georgi Kroumov NIKOLCHEV
Research Laboratory for Metal Forming and Work Hardening
Technical University Varna, BULGARIA
The concept of improving the tooth cavity's fill in forging of bevel gears
is based on the relationship between the initial height and impression's depth
of the preform. Through their optimal relation the bulge of the preform can be
limited and thereby the metal displacement to the die corners intensified.
Through an analytical determination of the bulging free surface at constant
friction and then its minimizing, it is shown that an optimal relation of the
preform's dimensions can be predicted. This concept is experimentally proved and
can be applied instead of using more complicated computing methods.

Key words: 
closeddie forging, bevel gear, hobbing, bulging, metal flow. 
TOP OF PAGE 
