Heat Transfer Modelling and Simulation of a 120 mm Smoothbore Gun Barrel During Interior Ballistics

Understanding the heat transfer phenomenon during interior ballistics and consequently presenting a realistic model is very important to predict the temperature distribution inside the cannon barrel, which influences the gun wear and the cook-off. The objective of this work is to present a new detailed numerical model for the prediction of thermal behaviour of a cannon barrel by combining PRODAS interior ballistics simulation with COMSOL simulation. In this study, a numerical model has been proposed for the heating behaviour of a 120 mm smoothbore cannon barrel, taking into account the combustion equation of the JA-2 propellant. Temperature dependent thermophysical properties of product gases were used for the calculation of the convective heat transfer coefficient inside the barrel. Projectile position, velocity of the projectile, gas temperature inside the barrel, volume behind the projectile and mass fraction during interior ballistics have been obtained by PRODAS software and used in the numerical model performed by COMSOL multiphysics finite element modelling and simulation software. Temperature simulations show that maximum wall temperature inside the cannon barrel is observed after 3 ms from fire, when maximum value of the convective heat transfer coefficient inside the barrel is observed. The results reveal that the convective heat transfer coefficient of burned gases inside the gun has major effect than the burned gas temperature on the heat transfer phenomenon.

Optimization of Heat Transfer Process in Double Gate MOSFET Using Modified BDE Model

In this paper, a nonlinear electrical model is derived and is used to calculate the electric field and the current density. To corroborate our electrical model, it was compared to TCAD simulator. It was shown that the proposed model captures the current density with a good degree of agreement with TCAD simulator. The electrical model is given by the modified Drift-Diffusion (D-D) model coupled with the Ballistic-Diffusive Equation (BDE) which is able to predict the heat transfer phenomenon in the nanoscale regime. The thermal device performance is then investigated by varying device parameters including gate and drain biases with implementation of different gate dielectric to explore its response on thermal characteristics. It was further shown that the proposed electro-thermal model is able to predict the nano heat conduction in (DG) nanostructure devices. In addition, it is shown that the heat flux process could be controlled by adjusting the drain and gate voltages.

Method of research for solar cookers performance characteristics- analysis and comparison

Cooking is one of the most common activity in day-to-day life of every woman. In rural areas the transportation of fuel is major problem and the increasing demand of energy for cooking applications is gaining importance and various investigations are being carried out for performance enhancement of the solar cooker. The box-type solar cooker has a complex thermal analysis due to the transient heat transfer phenomenon involved in three dimensions. A comparison of the standard correlation available are analysed for accuracy of predicted results with experimental data. The investigation involves the experimental determination of the parameters viz. wind heat transfer coefficient, side and bottom loss coefficient, inner and outer glass temperature. The extensive data is analysed with that of standard correlations and the significance of the experimental data is checked. Analysis found to have deviation of 3%-20% in experimental and correlation data, which indicates that for accuracy of performance analysis the studied parameters should be determined experimentally.

Mathematical Analysis of Thermal Energy Distribution in a Hybridized Mixed Convective Flow

The mixed convective flow of hybrid nanofluid (SWCNT-MWCNT/EG) containing micropolar fluid past a Riga surface embedded in porous medium is explored in detail throughout this study. In the momentum equation, the Darcy Forchheimer effect is used. The heat transfer phenomenon is exploited with viscous dissipation and thermal stratification over a non-Fourier heat flux model. PDEs are transformed into the necessary governing equations using transformations. The numerical results of non-linear governing equations are collected using Matlab function bvp4c. Graphical representations of the effects of relevant parameters on velocity, skin friction, and temperature are shown. The comparison of simple nanofluid and hybrid nanofluid is discussed in graphs. The temperature field is higher for hybrid nanofluid than simple nanofluid when solid volume fraction enhances. With increasing solid volume fraction, porosity parameter, and mixed convection parameter, the axial friction factor rises. The momentum boundary layer is inversely proportional to the slip parameter, Hartman number, variable viscosity and the porosity parameter.

A study of elastico-viscous fluid flow by a revolving disk with heat dissipation effects using HAM based package BVPh 2.0

Von Kármán problem of infinite disk is re-examined when fluid under consideration is elastico-viscous, satisfying the constitutive relations of Walters-B model. Main target here is to demonstrate how the presence of elasticity alters heat transfer phenomenon for the said problem especially when heat dissipation term is included in the analysis. We assume a self-similarity solution that results in a system of coupled non-linear equations. An easy to use package BVPh 2.0 based on the homotopy analysis method is used to present series solutions for values of elastico-viscous fluid parameter ($$K$$ K ) in the range $$0 \le K \le 1$$ 0 ≤ K ≤ 1 . Residuals are evaluated numerically at various order of approximations which depict that obtained solutions converge to the exact solutions. Boundary layer is substantially suppressed due to the consideration of elastico-viscous fluid assumption. Furthermore, velocity of the entrained fluid is inversely proportional to the parameter $$K$$ K . The results predict a substantial drop in heat transfer rate whenever elasticity effects are present. A considerable role of heat dissipation towards thickening of thermal boundary layer is apparent from the findings.

Thermo-fluidic transport of electromagnetohydrodynamic flow of sodium alginate based Casson nano fluid passing through a porous microtube under the effect of streaming potential

Thermal transport characteristics of Casson nanofluid through a porous microtube is analyzed under the effect of streaming potential and constant pressure gradient with electrokinetic effect associated with applied magnetic field. An analytical solution of the velocity and temperature distribution of Casson-nano fluid through the porous microtube related to combining effects of electromagnetohydrodynamics forces under the effect of streaming potential have been obtained. The significant influences of various non-dimensional parameters on velocity and temperature profiles are discussed in this study. Also, it is revealed the impact of nano particles on flow transport and heat transfer phenomenon. Furthermore, the Nusselt number is calculated analytically. The variations of pertinent parameters such as Hartmann number, Darcy number,Casson parameter, volume friction parameter of nanoparticles, joule heating parameter are delineated graphically and discussed in details.