Thermo Creep Transition in Non-homogeneous Thick-walled Rotating Cylinders

Creep stresses have been derived using transition theory. The results for the combined effects of angular speed and temperature are calculated and depicted graphically. It has been observed that a cylinder made of less compressible material at the internal surface and highly compressible at the outer surface is on the safer side of the design for different values of N, W2 and temperature as compared to highly compressible material at the internal surface and less compressible at the outer surface.Defence Science Journal, 2009, 59(1), pp.30-36, DOI:http://dx.doi.org/10.14429/dsj.59.148

Elastic-plastic Transition of a Non-homogeneous Thick-walled Circular Cylinder under Internal Pressure

Elastic-plastic stresses have been derived for a cylinder under internal pressure using Seth's transition theory. The effect of non-homogeneity has been discu ssed numerically and depictedgraphically. It has been observed that a cylinder made of non-homogeneous material with nohomogeneity increasing radially requires a higher percentage increase in pressure to becomefully plastic than to its initial yielding as compared to a homogeneous cylinder and is on the safer side of the design

Spray drier simulation and air flow pattern studies

The literature pertaining to the key stages of spray drying has been reviewed in the context of the mathematical modelling of drier performance. A critical review is also presented of previous spray drying models. A new mathematical model has been developed for prediction of spray drier performance. This is applicable to slurries of rigid, porous crust-forming materials to predict trajectories and drying profiles for droplets with a distribution of sizes sprayed from a centrifugal pressure nozzle. The model has been validated by comparing model predictions to experimental data from a pilot-scale counter-current drier and from a full-scale co-current drier. For the latter, the computed product moisture content was within 2%, and the computed air exit temperature within 10oC of experimental data. Air flow patterns have been investigated in a 1.2m diameter transparent countercurrent spray tower by flow visualisation. Smoke was introduced into various zones within the tower to trace the direction, and gauge the intensity, of the air flow. By means of a set of variable-angle air inlet nozzles, a variety of air entry configurations was investigated. The existence of a core of high rotational and axial velocity channelling up the axis of the tower was confirmed. The stability of flow within the core was found to be strongly dependent upon the air entry arrangement. A probe was developed for the measurement of air temperature and humidity profiles. This was employed for studying evaporation of pure water drops in a 1.2m diameter pilot-scale counter-current drier. A rapid approach to the exit air properties was detected within a 1m distance from the air entry ports. Measured radial profiles were found to be virtually flat but, from the axial profiles, the existence of plug-flow, well-mixed-flow and some degree of air short-circuiting can be inferred. The model and conclusions should assist in the improved design and optimum operation of industrial spray driers

Thermal creep analysis of pressurized thick-walled cylindrical vessels

Thermal stresses are calculated in thick-walled circular cylinder under internal and external pressure. The concept of transition theory and generalized strain measures is employed for the creep analysis of thick-walled cylinder. The mathematical modelling details of the methodology applied in this analysis are discussed extensively. Analytical method of solution has been applied to simplify the governing differential equations. The obtained results are presented in terms of graphs. On the basis of analysis, it has been deduced that less compressible thick-walled circular cylinder with thermal effects under the influence of internal and external pressure with non-linear measure is a better alternative for design engineers as compared to other cylinders

Thermal creep analysis of pressurized thick-walled cylindrical vessels

Thermal stresses are calculated in thick-walled circular cylinder under internal and external pressure. The concept of transition theory and generalized strain measures is employed for the creep analysis of thick-walled cylinder. The mathematical modelling details of the methodology applied in this analysis are discussed extensively. Analytical method of solution has been applied to simplify the governing differential equations. The obtained results are presented in terms of graphs. On the basis of analysis, it has been deduced that less compressible thick-walled circular cylinder with thermal effects under the influence of internal and external pressure with non-linear measure is a better alternative for design engineers as compared to other cylinders