Leather is an important economic commodity. The feel of the leather invariably decides the quality of the leather. The rate and mode of drying alters the physico-mechanical properties of the leather significantly. Typically, in leather manufacture wet leathers with about 70% moisture levels are subjected to mechanical squeezing operation, samming, for removal of freely held water before subjecting to conventional drying processes to produce leathers with 15– 20% moisture. Experiments are conducted to gain a clear picture of how drying variable affects the mechanical properties of dried leathers. Shorter drying time and proper initial water content are favorable conditions to produce stronger and softer leather. Possibility have been explored of using mass quantity such as drying rate to generalize relationship between drying variables and mechanical properties. From the experiments, it can be concluded that by vacuum drying process stronger and softer leather can be achieved, which will have high tensile strength, grain crack strength and tongue tear strength. Further they would not undergo any wear and tear during finishing processes.
This book provides a comprehensive analysis of heat and mass transfer effects on magnetohydrodynamic convective flows. Basic idea are stressed and discussed in detailed full developments of results are provided. It helps researchers, students and engineers and scientists who work in the area of heat transfer heat transfer on magnetohydrodynamic convective flows. Applications of the problem are also discussed.
Viscosity and thermal conductivity are two temperature dependent properties of matter. In most of the problems of fluid mechanics, the viscosity and thermal conductivity of the fluid were assumed to constant. However it is known that these physical properties can change significantly with temperature.When the effect of variable viscosity and thermal conductivity are taken in to account, the flow characteristics are substantially changed from that of constant cases. Most fluids however have temperature dependent properties, and under circumstances where large temperature gradients exist across the fluid medium, fluid properties often vary significantly. Under many conditions, ignoring such variations may cause serious in-accuracy in estimating heat transfer rates. So, here in this book we are considering some heat and mass transfer problems of fluid mechanics where the effects of variable viscosity and thermal conductivity are observed under different flow conditions. The book will be helpful for researchers working in the field of heat and mass transfer flow.
The mathematical model describing the different aspects of physical problems as well as numerical method adopted for their solution have been introduced and discussed. The different phases of overall numerical solution procedure from their non-dimensional form through the similarity transformation to the solution of flow equations have been described. The boundary layer flow around bodies of different shapes like shrinking sheet, cylinder, inclined plate, moving surface, moving vertical plate, cone immersed in the fluid have been studied. These mathematical models are commonly encountered in many studies in aerodynamic, chemical engineering, hydrodynamic, wind engineering and ocean engineering etc. The study of various effects like chemical reaction, viscous dissipation, magnetic effect, thermal radiation etc. have been made to study their effects on velocity, temperature and concentration. The quantities of physical interest viz. skin friction, Nusselt number and Sherwood number have also been calculated and their analysis included in the study.
FLOW PROBLEMS WITH HEAT AND MASS TRANSFER. In this Dissertation, investigations are carried out on Natural convection flow of fluid between two infinite vertical parallel plates for different physical situations as well as different fluid properties. The different thermal conditions considered in this dissertation include symmetric and asymmetric heating of the boundaries, periodic temperature variation on the boundaries, viscous dissipation heating as well as the role of Non- Fourier energy equation on convective heat transfer. The dissertation also investigated the influence of heat generation or absorption and mass leakage (suction/injection) through the channel boundaries. Closed form solutions are obtained for momentum, energy and concentration equations for different physical situations. It is hoped that the result presented in this dissertation will be of use in validating Computer routines for numerical solutions of more complex natural convection fluid flows in the presence of heat and mass transfer and in stimulating needed experimental work in this area.
Higher energy consumption and storage loss beyond permissible limit are the two most important problems in Indian potato cold stores, which have been hindering with the further growth of this industry. The problems of energy consumption and storage losses are interrelated in nature and have direct relation with the intricacy of the coupled transport phenomena of heat, mass and momentum transfer in bulk-stored potatoes. The heat and mass transfer processes within the bags of potato in a stack depend on product properties, and operating as well as geometric parameters of the cold store. All these parameters influence the mechanism of heat and mass transfer in the storage facility, which ultimately affect the temperature of the packed product and humidity around the product.Therefore, an in-depth analysis of the relative importance of these parameters on the mechanism of transport phenomena within the bulk-stored potatoes in a cold store helps to overcome the problems of higher energy consumption and storage losses beyond permissible limit.
The use of microwave energy for processing materials has the potential to offer many advantages in reduced processing times and energy savings. In conventional thermal processing, energy is transferred to the material through convection, conduction, and radiation of heat from the surfaces of the material. In contrast, microwave energy is delivered directly to materials through molecular interaction with the electromagnetic field. In heat transfer, energy is transferred due to thermal gradients, but microwave heating is the transfer of electromagnetic energy to thermal energy and is energy conversion, rather than heat transfer. This difference in the way energy is delivered can result in many potential advantages to using microwaves for processing of materials. Because microwaves can penetrate materials and deposit energy, heat can be generated throughout the volume of the material.so we can said that, microwave is a new technology which can replace conventional heating in most of textile processes.
1stchapter, a two dimensional MHD natural convection and mass transfer flow past an inclined semi infinite vertical plate in the presence of heat generation and porous medium was discussed 2ndchapter, a free convective flow of viscous incompressible fluid of small electrical conductivity through a porous medium bounded by an oscillating infinite porous plate in slip flow regime. 3rdchapter, an analysis carried out to study the nonlinear MHD flow with heat and mass transfer characteristics of an incompressible, viscous, electrically conducting Boussinesq fluid over a vertical oscillating porous permeable plate embedded in a porous medium. 4thchapter, a theoretical analysis of influence of radiation effect on a two dimensional MHD convection and mass transfer flow of an electrically conducting fluid past an inclined semi-infinite vertical porous plate embedded in a porous medium. 5thchapter, a theoretical analysis of free convective two dimensional unsteady flow of a visco-elastic incompressible fluid through a porous medium bounded by an infinite vertical porous plate subjected to a uniform suction was presented under the influence of a uniform transverse magnetic field.
The effect of chemical reaction,radiation absorption and thermo-diffusion on MHD convective heat and mass transfer flow in Channels / Ducts with heat sources gives the study of heat generation or absorption effects in moving fluids, such as fluids undergoing exothermic or endothermic chemical reaction. Due to the fast growth of electronic technology, effective cooling of electronic has become warranted and cooling of electronic equipment ranges from individual transistors to main frame computers and from energy suppliers to telephone switch boards and thermal diffusion effect has been utilized for isotopes separation in the mixture between gases with very light molecular weight (hydrogen and helium) and medium molecular weight.
Urea prills are produced in the prilling tower, where a cooling-solidification-cooling process of the prills takes place. The ambient air is used as the cooling stream for this process. A case study of the urea prilling process is chosen due to in hot/humid days, the temperature of the product at the bottom of the prilling tower is hot and cannot be packed directly. In addition, the urea prills form lumps and cakes with each other on the scrubber at the bottom of the prilling tower that affects the quality of the product. A mathematical model based on the particle kinematics,and, heat and mass transfer between the urea prills and the cooling air is developed. This is followed by using a numerical technique with an explicit scheme to solve the model. The model numerical results are validated with Scanning Electronic Microscope (SEM) observation of urea particles. Moreover,to investigate the effect of the urea prilling tower configuration parameters on the above urea product problems, the hydrodynamic of air flow inside the tower is analyzed using Computational Fluid Dynamics (CFD) simulation software.
Styrikovich ?heat? And Mass Transfer Sourcebook – 5th All–union Conference, Minsk, 1976