Thermal Decomposition Behaviour of Foundry Sand for Cast Steel in Nitrogen and Air Atmospheres

Sand casting is the most widely used casting technique, known for ages, even since ancient times. The main goal of this study was to determine the thermal decomposition behaviour of foundry sand for cast steel. We first tested the basic properties of foundry sand, including its proximate analysis, chemical composition, and particle size characteristics; we next monitored the thermal decomposition behaviour of foundry sand for cast steel via simultaneous thermal analysis. We focused on the mass loss of foundry sand for cast steel at different heating rates in nitrogen and air atmospheres. We adopted a novel method to calculate the volatile release characteristic index of foundry sand. The volatile content of foundry sand for cast steel was very low, so the volatile release characteristic index of the sand could not be strictly calculated according to this concept. We calculated the thermal decomposition kinetics parameters of foundry sand, namely, the activation energy and preexponential factor, under kinetics theory. To thoroughly test the fitting effect, we conducted a single-factor analysis of variance on the source of error. The results showed that the independent variable has a significant influence on the dependent variable and that the fitting equation we selected is feasible and effective.

On the possibility to decrease the fuel consumption for a heavy-duty truck Diesel engine using the Turbo-compound method: a case study

The reduction of Diesel internal combustion engines emissions is one of the major concerns of the engines manufacturers. Despite the fact that the efficiency of the gas post-treatment systems has been significantly improved, decreasing the smoke and the soot from the cylinder inside remains a main research goal. This work is proposing a theoretical study on these pollutants formation for different kinds of direct injection methods. By dividing the in-cylinder injection the heat release characteristic could be modified, leading to different temperature and pressure levels. Using exhaust gas recirculation (EGR) the reduction of the gas temperatures might also be decreased, limiting NOx formation. To evaluate the level of the cylinder gas emissions formation a two-step procedure could be followed. First, by using a numerical calculation system the heat release characteristic can be highlighted concerning a Diesel engine with stratified injection; then, using an experimental relationship applying a large data base, the amount of the gas emissions can be subsequently provided. The authors propose some combinations between injection characteristics and EGR used fractions which could generate successfully results speaking in terms of NOx, soot and smoke formation.