A feasibility study of real-time monitoring techniques for scale deposition thickness in pneumatic conveying pipelines

In this study, the feasibility of two techniques for real-time monitoring of scale deposition thickness were evaluated. Traditional pressure drop measurements and a variant of the heat pulse monitoring technique which was developed in this study were tested and compared in a lab scale experiment. Measurements were performed on test pipes while transportation air was led through the conveying system. Coating layers of different thicknesses were applied to the inner walls of the test pipes to simulate scaling. Prediction models were calibrated from the experimental data by multivariate methods and were used to assess the performance of the techniques. It was found that the heat pulse method provided the most accurate predictions for scale thickness. The pressure drop method did not give acceptable results for the application considered in this paper. Results show that the heat pulse method is somewhat sensitive to changes in the feed air temperature. However, it will still provide reliable results for online monitoring of industrial applications in which the conveying air temperature is relatively stable.     

A simple method for prediction of heating and cooling cooling in solids of various shapes

Methods for prediction of temperature-time profiles in solids undergoing heating or cooling are examined. Because physical data are often uncertain a prediction method that is accurate to ±10% is adequate in many situations. A procedure is proposed that meets this criterion, is simple to use, and is applicable to a wide range of regular and irregular shapes. The method introduces a concept of the number of equivalent heat transfer dimensions to take account of the solid's geometry. Alignment charts can then be used to find the centre temperature of a body as a function of time and the external heat transfer conditions.     

A simple method for prediction of heating and cooling cooling in solids of various shapesUne méthode simple de prévision du taux de réchauffage et de refroidissement dans des solides de diverses formes

Methods for prediction of temperature-time profiles in solids undergoing heating or cooling are examined. Because physical data are often uncertain a prediction method that is accurate to ±10% is adequate in many situations. A procedure is proposed that meets this criterion, is simple to use, and is applicable to a wide range of regular and irregular shapes. The method introduces a concept of the number of equivalent heat transfer dimensions to take account of the solid's geometry. Alignment charts can then be used to find the centre temperature of a body as a function of time and the external heat transfer conditions.     

A mathematical model and a heuristic approach for design of the hybrid manufacturing systems to facilitate one-piece flow

One-piece flow is a design rule that entails production in manufacturing cells on a ‘make one, check one, and move-on one’ basis (Black, J.T., 2007. Design rules for implementing Toyota Production System. International Journal of Production Research, 45 (16), 3639–3664), which reduces manufacturing lead time significantly. This paper proposes a sequential methodology comprised of a mathematical model and a heuristic approach (HA) for the design of a hybrid cellular manufacturing system (HMS), to facilitate one-piece flow practice. The mathematical model is employed in the cases of small- and medium-sized problems, and it attempts to minimise the total number of exceptional operations, while considering machine capacities and alternative machines. The machine-part matrix achieved by the mathematical model is input into the flow line design stage of the HA, where backflow within the cells is eliminated. However, for industrial problems, the proposed HA is utilised. After the formation of the cells by clustering, the HA attempts to eliminate exceptional operations of a given cellular configuration together with a functional structure by employing alternative machines, based on the decision rules developed. Later, unidirectional flow within the cells is achieved and the capacity and budget constraints are satisfied. A medium-sized problem is solved by using both of the approaches, namely, the model integrated with the flow-line design stage of the HA and the complete HA. The results are discussed and the limitations are explained.     

A non-lumped dynamic simulation method of sorption compressor for sorption cryocooler

A dynamic analysis of sorption compressor is motivated by the design of a practical sorption compressor. In this paper a non-lumped dynamic simulation method based on a non-isothermal parameter has been developed. An algorithm for simulating the dynamic behaviors of sorption compressor involving mass and energy transport is described and is calculated using Computational Fluid Dynamics (CFD). The calculated time-dependent pressure and temperature across the sorption compressor are obtained and verified by experiments. Then, the effects of thermal gradient and non-equilibrium adsorption–desorption on the net gas outflow from the sorption compressor are also investigated. It is shown that thermal gradient and non-equilibrium adsorption–desorption can significantly affect the net gas outflow with the same total heat input.     

A method and instrument for measuring the thermal properties of samples of a regenerative product in a matrix when they are heated by a constant heat flux

A mathematical model of a method of measuring the thermal properties of new regenerative products is developed. The construction of a measuring instrument is proposed. Experimental data on the thermal conductivity and volume heat capacity of regenerative products in a matrix are obtained. Translated from Izmeritel’naya Tekhnika, No. 5, pp. 49–53, May, 2009.