A mathematical model is developed and tested with plant data for the ammonia cold shot converter of Razi Petrochemical Complex. The model is based on a material and energy balance in a differential element of beds and is subjected to the assumptions of uniform distribution of temperature and composition through a general cross section and negligible mass and heat transfer in axial direction. Th...

In the current study, reduction of nitrogen oxide from exhaust gas in the presence of NH3 as reductant on selective catalytic reductant (SCR) impregnated catalytic converter was simulated using Comsol© software. Mass transfer (one-dimensional) and heat transfer (three-dimensional) governing equations were taken into account to model the unsteady state behavior of the catalytic converter. Modeli...

The main purpose of this work is to investigate the porous medium and diffusion-thermo effects on unsteady combined convection magneto hydrodynamics boundary layer flow of viscous electrically conducting fluid over a vertical permeable surface embedded in a high porous medium, in the presence of first order chemical reaction and thermal radiation. The slip boundary condition is applied at the p...

this paper presents a numerical simulation of developing flow and heat transfer of a viscoelastic fluid in a rectangular duct. in fully developed flow of a viscoelastic fluid in a non-circular duct, secondary flows normal to the flow direction are expected to enhance the rate of heat and mass transfer. on the other hand, properties such as viscosity, thermal conductivity, specific heat and rela...

nucleate pool boiling heat transfer coefficient have been experimentally measured on a horizontal rod heater for various liquid binary mixtures. measurements are based on more than three hundred data points on a wide range of concentrations and heat fluxes. in this investigation, it has been confirmed that the heat transfer coefficient in boiling solutions are regularly less than those in pure ...

this paper describes the theoretical and experimental investigations of the key components and also the performance analysis of a rotary wheel for using as a solid desiccant dehumidifier and also indirect evaporator cooling system. solid desiccants have long been used in dehumidification and cooling systems for energy efficiency or reduce electricity. although many mathematical models on the ro...

If a mature sporangiophore is placed next to a barrier that is moving in a clockwise direction, it grows both away from the barrier and into the wind; the wind is generated by the moving barrier itself. When the barrier is moving in a counterclockwise direction, the sporangiophore grows towards both the barrier and the wind. The net direction of growth appears to be the vector sum of the rheotr...

In this article, stream flow effectivness is based on hydraulic network studied in the shell-side of a shell and tube heat exchange as a case study. For an appropriate heat exchangers rating design to meet a specified duty, it's better to consider each stream flow separately. Using the hydraulic network principals, a set of the correlations for calculating different stream flow rates in the cro...

The aim of the present study was to propose a panel being sensitive to the direction of heat transfer. For this purpose, a vertical rectangular cavity with prescribed dimensions was prepared and filled with water as the working fluid. A vertical mid-plane solid partition was installed within the cavity. Two relatively wide openings were created at the top and bottom of the partition and they we...

In this research mass transfer coefficient under jetting regime in different directions (from dispersed to continuous and continuous to dispersed phase) has been studied using an experimental setup. n-Butanol-succinic acid-water with low interfacial tension has been selected as experimental chemical system. The effects of various parameters such as jet velocity, nozzle diameter and the heig...