Fazlar Rahman

Fluid flow in the lid driven cavity is a well-known phenomenon in the realm of fluid flow and heat transfer. Different cavity shapes such as square, circular, trapezoidal, and hexagonal have already been studied. However, most of the parametric analyses have previously been done using one specific cavity shape design. The present study intends to generalize the cavity design for a larger range of applications starting from the selection of cavity form due to the enhancement of heat transfer inside that selected cavity for different boundary conditions. Numerical studies using a finite element solver have been carried out to investigate the physics of fluid flow and heat transmission in a cavity where a wall of the enclosure is moving. In this research, the average Nusselt number for six distinct shaped lid-driven cavities is studied (e.g., square, rhombus, circular, rounded rectangular, trapezoidal and hexagonal). The hexagonal-shaped cavity has the largest Nusselt number of all of ...

In this paper, an experimental study of a concentric staggered annular fin with radial outlets and a staggered rectangular fin with lateral outlets for steady-state natural convection, and forced convection is presented. The objective of this work is to investigate the effect of shape, profile and arrangement of the fins in heat transfer with minimum blockage ratio, stagnation, and pressure drop. In this regard, the two different shapes of fins are designed with the same material, identical extended surface area, width, and thickness; and studied experimentally with identical thermal load and boundary conditions, as well as identical flow characteristics. In case of forced convection, the orientation of the base-plate of the fins is kept perpendicular to the direction of flow to achieve velocity vectors parallel to the fin surfaces. The overall heat transfer coefficient, fin efficiency, effectiveness, and temperature distribution of both fins are compared for different base-plate&#3...

High numbers of workplace casualties and injuries are reported each year in Bangladesh due to explosion of the boiler in the rice husking mills, as well as other industries including garments factories. Rice husking mills are using locally made steam boilers, which are fabricated of steel plate obtained from the ship breaking yard and not equipped with standard safety devices and fittings. The motivation of this work is to find the causes of explosion of those boilers and provide some modifications to reduce workplace casualties. In this regard, some rice husking mills in the rural area of Bangladesh are inspected to evaluate the working and operating condition of the boilers. The mechanical properties of steel plate obtained from the ship breaking yard is found by tensile test in UTM and those mechanical properties are used in numerical analysis of the boiler, which is currently operating in the rice husking mills and fabricated locally from same source of steel plate. The FEA tool...

A leaf spring is a simple form of spring commonly used for the suspension system in heavy duty vehicles which is originally called laminated or carriage spring. It performs the isolation task in transferring the vibration due to road irregularities to the passenger's body or goods transported on it. The advantage of leaf spring over helical spring is that the ends of the spring have been guided along a definite path as it deflect to act as a structural member in addition to an energy absorbing device. Increasing competition and innovations in the automobile sector, tends to modify the existing products with new or advanced material products. To improve the performance of the suspension system, many modifications have been taken place overtime but the recent innovations imply parabolic leaf spring and application of composite materials, as the composite materials have high strength-to-weight ratio compared to the conventional steels. The present work attempts to analyze the comparison between the conventional steel (AISI1030) leaf spring and the composite (Carbon/Epoxy) leaf spring with respect to static and fatigue analysis. Here static analysis determines the safe stress, deformation and corresponding pay load and also studies the behavior of structures under practical conditions. The research also focuses on fatigue analysis to determine its life cycle and also to observe its fatigue failure characteristics. The model of the leaf spring has been carried out into the CAD software. The analysis of the steel leaf spring has been divided into theoretical, experimental and simulation sections. The simulation of steel leaf spring has been validated with the theoretical and the experimental results. Further simulation has been done for composite leaf spring by FEA software. Finally, the result shows that the composite leaf spring has better load carrying capacity in reduced weight, and better fatigue behavior rather than the conventional steel material for the leaf spring.

The temperature and pressure response within control volume of a pneumatic system with thermal consideration is presented in this paper. The non-linear modeling equations of temperature and pressure are derived in a systematic way based on realistic estimation of heat transfer to the system, energy equation, ideal gas law and compressibility of fluid. The pressure and temperature response is compared analytically with the adiabatic condition and found that the system responds differently with thermal consideration.