The physicochemical characteristics of vegetable oils, the atomization and the particle size of the spray are fundamental aspects for the simulation of their combustion on burners. In this study, the influence of temperature and pressure on the disintegration of the jet of jatropha oil and its mixture with gas oil was simulated on a Riello Gulliver burner with power ranging from 22.5 to 35.6 KW. The disintegration and dispersion conditions of the droplets from the burner were determined using the average Sauter diameter by equations and mathematical functions. The results showed that there is a minimum temperature and pressure (130°C and 14 bar, respectively) from which it is possible to obtain an adequate disintegration of jatropha oil and its mixtures with diesel with suitable selected type of burner. These simulation results are consistent with results obtained experimentally and show satisfactory disintegration conditions at low pressure.

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In order to find heat production techniques for drying and heating applications of premises in tropical climates from process characterization studies, a flat air collector with air and forced convection was first designed. A simulation of solar radiation, thermal behavior of the solar collector and an experimental test of the latter were carried for validation. The time profiles of the evolution of solar radiation and the temperatures of the heat transfer fluid at the inlet and outlet of the collector as well as those of the collector components during a day were presented, November 17th, 2019. During this day, for an ambient air temperature at the collector inlet varying between 20°C and 41°C, the experimental temperatures of the absorber and solar collector outlet air temperature are respectively 96°C and 78°C for maximum measured solar irradiation of the order of 900 W/m 2 . For the same interval of variation of ambient air temperature, the simulated temperatures of the absorber and of the solar collector outlet air are respectively of the order of 105°C and 90°C when the simulated maximum solar irradiation attains 880 W/m 2 of collection at true solar noon. The values of R2 obtained for the data of the solar radiation, collector outlet air temperature and temperatures of the absorber are respectively of the order of 0.960, 0.98 and 0.950, indicating a good correlation between the experimental and predicted data; whereas the root mean square error (RMSE) are respectively around 0.020, 0.013 and 0.011, showing a very good match between experimental and modelled temperatures. The temperature range at the outlet of the present device which is simple and achievable at low cost is important for the drying needs of the various products and heating.

This work is largely devoted to a review of existing works in the literature on single and multi-zone models of thermodynamic combustion in a diesel engine. It is found that numerical simulations of diesel engine operation based on thermodynamic models are of great interest in predicting engine performance and developing new concepts.  Also, the advantages and disadvantages of the different models of a multi-zone are given. This study summarises several studies over several years of these thermodynamic models in use by presenting the different results.  The limitations of the single-zone model led to the development of the multi-zone thermodynamic combustion model. This work therefore suggests a comprehensive study that takes into account the different models (kinetics, fuel flow, injection, heat transfer, etc.) to better appreciate the performance of the diesel engine.  This will give a clear idea of how to develop new concepts for single-zone or multi-zone thermodynamic modelling that will help car manufacturers, for example.