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A Simplified Correlation
for Forced Convective Heat Transfer
in Tape-Generated Swirl Flow of Air
-- M S N Murty, K V Ramesh, G M J Raju and Y S P Narayana Rao
The forced convective heat transfer data are generally correlated as a function of flow rate, physical
properties of fluid and geometry of the system. The proposed equations are generally complex, as revealed by
literature. However, heat transfer coefficient data can be predicted from a single simple equation for a variety
of geometries. This method helps in reducing the time and cost of experimental investigations. The
forced convective heat transfer coefficient data obtained with full length twisted-tape inserts used for flow of air
are well-correlated as Nu = 2.34
(Remod)0.2448. In this equation Nu is Nusselt number and Remod is modified Reynolds number. It is to be noted that this equation is without the aid of Prandtl number and the tape twist ratio.
This study confirms that a simplified method is possible for correlating the forced convective heat transfer
data without the aid of Prandtl number and the additional geometrical parameters of the system.
© 2009 IUP. All Rights Reserved.
Generic Model Controller with Adaptive State Estimation for Nonlinear
Cstr
-- Dipesh S Patle and Hare Krishna Mohanta
A hybrid control scheme consisting of a generic model control (GMC) and a nonlinear adaptive state
estimator (ASE) is designed. The ASE estimates the partially known parameters in the presence of
process/predictor mismatch, whereas GMC takes care of the nonlinearities and interactions in the nonlinear
industrial processes. The developed GMC-ASE controller is implemented in a jacketed continuous
stirred-tank reactor (CSTR). The performance of the developed controller is compared with a
conventional proportional-integral (PI) controller. It is observed that a GMC-ASE controller shows relatively
better performance than the PI controller due to the exponential error convergence capability of the ASE
estimator and high quality performance of the GMC controller.
© 2009 IUP. All Rights Reserved.
Analysis of Momentum Transfer
with Coaxially Placed Disc as Turbulence Promoter
in Circular Conduits
-- V Nageswara Rao and N Chitti Babu
Studies on the effect of coaxially placed entry region disc as turbulence promoter on momentum
transfer rates in forced convection flow of electrolyte were conducted. The study covers various diameters of the
disc (Dd). Within the range of variables covered, the augmentation achieved in friction factor was found to be
5-fold over the tube flow in absence of promoter. Momentum transfer rates were analyzed with
momentum transfer roughness function and roughness Reynolds number. The following correlation was reported
from the study R(h+) = 0.0009
(Re+)1.125 (f5)_0.869.
© 2009 IUP. All Rights Reserved.
Effects of Physicochemical Conditions
on Ceramic Cross-Flow Microfiltration
of Mineral Dispersions
-- P Mikulášek
In this paper the influence of dispersion pH, ionic strength, and coagulant type on ceramic
membrane microfiltration of TiO2 dispersions were studied. A series of cross-flow microfiltration experiments
were carried out at various pH values, ionic strengths and with various multivalent inorganic salts.
Filtration behaviors were analyzed based on measurements of zeta potential of alumina membrane and
TiO2 particle and particle size distribution of the
TiO2 suspension. The results showed that inorganic anions affect
the microfiltration of TiO2 dispersion by changing the surface properties of both the alumina membrane
and TiO2 particle. The solution environment affects the dispersion of
TiO2 particles and plays a major role in
the filtration flux.
© 2009 IUP. All Rights Reserved.
Modeling of Liquid-Liquid Phase Transfer
Catalysis Based on Interfacial Mechanism
-- Sunil K Maity
The liquid-liquid phase transfer catalyzed reaction of benzyl chloride with aqueous ammonium sulfide
is modeled based on interfacial mechanism considering the reaction kinetics in the organic phase and
ionic equilibrium in the aqueous phase. The rate constants and equilibrium constants of the developed model
are estimated at different temperatures using an indigenously developed algorithm based on
Levenberg-Marquardt. The frequency factors and activation energies of the rate constants are determined from
an Arrhenius plot of ln (rate constants) versus 1/T. The calculated results based on the developed model
using the estimated reaction parameters are compared with the experimental observations, and quite a
good correlation is observed.
© 2009 IUP. All Rights Reserved.
Chemical Process Engineering
in Marine Biotechnology: Opportunities and Challenges
-- Shaik Basha, Z V P Murthy and Bhavanath Jha
Chemical process engineering is the critical link that transforms basic research discoveries into
commercial reality. The role of chemical process engineering in marine biotechnology, as the technology of
industrial exploitation of biochemical marine systems, is illustrated. The scientific disciplines underlying
biotechnology are pointed out. Chemical engineering is described as an established discipline, drawing upon
chemical, biological and engineering sciences, and concerned with design, development, implementation and
operation of processes and process plant for handling biological materials. The present status of chemical
process engineering in marine biotechnology has been described. Key engineering challenges, including
design, development, modeling and evaluation of sustainable production systems employing
phototrophic organisms, development of metabolic engineering and immobilized cell and enzyme
bioreactors, environmental aspects of large-scale photobioreactors, and bioproduct formulation, especially with
reference to stability and functionality are presented.
© 2009 IUP. All Rights Reserved.
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