| || Heat and Mass Transfer in a Semi Infinite Porous Medium in Contact with Well Stirred Fluid
Author : Narang, H.N.
Source : Defence Science Journal ; Vol:20(1) ; 1970 ; pp 29-38
Subject : 532.542 Fluid Dynamics
Keywords : Mass transfer ;Heat flux;Capillary porous medium
Abstract : Unsteady transfer of heat and mass in a semi-infinite capillary-porous medium in contact with well-stirred fluid has been considered in this paper. At the interface, we have assumed the continuity of temperature and of heat flux while for mass transfer convective law has been assumed. It is also assumed that a quantity of heat, proportional to the moisture transferred at the interface, is produced with in the fluid. Some numerical results have been graphically depicted.
| || Inverse Estimation of Time-varied Heat Flux and Temperature on 2-D Gun Barrel using Input Estimation Method with Finite-element Scheme
Author : Chen, Tsung-Chien;Liu, Chiun-Chien
Source : Defence Science Journal ; Vol:58(1) ; 2008 ; pp 57-76
Subject : 623.4 Armaments and Ballistics;620.261 Explosives
Keywords : Heat flux;Input-estimation method;Finite element scheme;Inverse heat conduction;Inverse estimation
Abstract : When a gun fires, a large amount of heat flux is triggered by the propellant gas acting on the gun barrel inner wall, leading to the rise of temperature, which will cause serious destruction. In this paper, an inverse method based on the input-estimation method including the finite inverse heat conduction problem (IHCP) element scheme to inverse estimate the unknown heat flux on the 2-D gun barrel has been presented. The use of the online accuracy to inversely estimate the unknown heat flux on the chamber has been made using 7.62 mm gun barrel outer wall temperature measurement data. Using simulation uniform and non-uniform heat flux q(z,t) cases involves a gun barrel inner wall that varies with time t and the axial z-location with convection situation in the outer surface. Computational results show that the proposed method exhibits a good estimation performance and highly facilitates practical implementation.
| || Some Observations on the Ignition of Composite Solid Propellants
Author : Mohandas, K. ;Nagarajan, R.;Sankaralingam, S.;Kishore, K.
Source : Defence Science Journal ; Vol:45(3) ; 1995 ; pp 243-254
Subject : 662.3 Propellants;66 Chemical Technology
Keywords : Propellant ignition ;Pyrolysed polymer products;Heat flux
Abstract : Heat-up times derived from studies on the ignition characteristics of a few model composite solid propellants, containing polystyrene, carboxy-terminated polybutadiene, plasticised polyvinyl chloride and polyphenol formaldehyde as binders, show that they are directly proportional to the mass of the sample and inversely proportional to the heat flux. Propellant weight-loss prior to ignition and high pressure ignition temperature data on the propellants, ammonium per chlorate, and binders show that the ignition is governed by the gasification of the binder pyrolysis products. The activation energy for the gasification of the pyrolysed polymer products corresponds to their ignition behaviour suggesting that propellant ignition is controlled by the binder.