Function Of Contact Pressure Research Articles

Fast pyrolysis of wood: direct measurement and study of ablation rate

Quantitative measurements of the apparent rate of reaction of wood rods undergoing fast pyrolysis by contact with a hot spinning steel disc are reported. The variations in the apparent volatilization rate and in the thickness of the reacting layer were studied as a function of disc velocity, rod diameter, contact pressure and disc temperature. The results show that the rate of reaction is mainly limited by heat transfer outside and inside the wood (ablation conditions). The external heat transfer coefficient, studied as a function of contact pressure, is much more important than the heat transfer coefficient calculated on the basis of simple radiation transfer. The conclusion is that fast pyrolysis of wood in the ablation regime can be observed if two necessary conditions are fulfilled : high available heat flux and efficient removal of the primary products of the reaction.

プラテン型ベルト研削の適応制御

Although belt grinding has recently been regarded as an equally important and popular processing to ordinary grinding, few of systematic or quantitative investigation have been conducted, this leaving belt grinding at the stage of sophisticated know-hows. From this standpoint belt grinding is one of the most effective and attractive application field of adaptive control.In belt grinding the continuous increase of contact pressure has been experimentally demonstrated to be highly advantageous from the viewpoint of economics. The objective function of grinding cost which is the function of contact pressure and belt life has been introduced as a general state equation. By determining the constants involved in the equation in an on-line manner and anticipating the cost successively, the optimal mode of pressure increase and belt life can be obtained.

The Use of Analog Computers for Determining Surface Parameters Required for Prediction of Thermal Contact Conductance

The mathematical analysis of a thermal contact by Fenech and Rohsenow requires knowledge of certain parameters describing the geometry of the contact interface. These parameters are volume average thickness of the void above and below the plane of the contact, the number of contacts per unit area, and the ratio of the actual contact area to the total area. The authors outline a method for determining these parameters graphically. This paper describes a method for obtaining analog voltages of surface profiles of contacting surfaces and the application of a general purpose analog computer to determine the geometric parameters of contact as a function of contact pressure. The results of applying this method are combined with the analysis of Fenech and Rohsenow. The predicted contact conductance is found to agree well with experimental data at mean contact temperatures of 100, 200, and 300 F for load pressures of 100 to 20,000 psi.