The output of the latent heat storage devices (LHSDs), based on some phase change materials (PCMs), depends upon the thermophysical properties of the phase change material used. In this study, a paraffin-based nanofluid, blended with aluminum oxide (Al₂O₃) nanoparticles, is used as PCM for performance evaluation. A three-dimensional (3D) numerical model of regenerative type shell-and-tube LHSD is prepared using COMSOL Multiphysics^® 4.3a software to estimate the percentage of melt and the average temperature of the analyzed nanofluids. The results of this study are in close agreement with those reported in the literature, thereby ensuring the validation of the numerically predicted results. The effects of adding the nanoparticles on the rate of melting, as well as solidification and rate of stored/liberated energy, are studied. The results revealed that, by adding 10% nanoparticles of Al₂O₃, the melting rate of pure-paraffin-based LHSD improved by about 2.25 times. In addition, the rate of solidification was enhanced by 1.8 times. On the other hand, the heat of fusion and specific heat capacities were reduced, which, in turn, reduced the latent and sensible heat-storing capabilities. From the outcomes of the present research, it can be inferred that combining LHSD with a solar water heater may be used in technologies such as biogas generation.

In the present work, the effect of porosity and loading height on the performance of the domestic gas burners, using LPG as fuel, is studied extensively through experimentation. Water Boiling Test (Version 4.2.3) as per the recommendations of International Organization for Standardisation International Workshop Agreement (ISO-IWA) is adopted to determine the thermal efficiency of the domestic gas stove. It is observed that, by increasing the number of holes in intermediate and innermost rows by about 96% and 73%, the pitch gets reduced by 58% and 65% respectively. Due to increased porosity, the thermal efficiency in hot and cold phase is increased by about 30% and in simmer phase the thermal efficiency is increased by about 26%. In addition to this, it is also observed that there exists an optimum height for keeping the container over the gas burner (loading height) up to which the thermal efficiency increases and beyond that, the thermal efficiency drops significantly. The optimum loading height for cold and hot phase is 14.1, and 14.6 mm respectively for the LPG cookstove used in present work (1–3 kW). The thermal efficiency at cold and hot phase, while running the gas stove with stand (11.25 mm) is reduced by about 18.5 and 16.5% respectively compared to the optimum loading height of 14.1 and 14.6 mm respectively.

This paper presents the computational analysis of flames that are numerically modeled over heat flux burners at 298 K and 1 bar. ANSYS Fluent® software is used for conducting two-dimensional (2D) simulations. The conventional heat flux burner with 0.7 mm pitch and 0.5 mm diameter can measure the laminar burning velocities of gaseous fuel mixtures up to 60 cm/s. The effort is laid to design a tapered burner plate with hole diameter of 0.5 mm at inlet and 0.3 mm at outlet having pitch of 0.7 mm, capable of eliminating the limitations of the conventional heat flux burner. The simulations were based on the data provided in the literature and were performed at ambient pressure (1 bar) and temperature (298 K). The detailed numerical analysis shows that the flame height increases on reducing the diameter and pitch (increasing porosity) simultaneously. On the other hand, flame height decreases by decreasing the pitch, keeping the diameter constant. Furthermore, the rate of chemical reaction increases sharply on decreasing the pitch by 0.1 mm, whereas it decreases considerably on decreasing the diameter and pitch together. The thermal properties of the flame stabilized over the tapered heat flux burner are comparable to that of the conventional heat flux burner model. The current work proposes to use tapered burner design for the development of an adiabatic flat flame on the heat flux method for mixtures having laminar burning velocity beyond 60 cm/s.