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Numerical simulations are used to analyze the thermal performance of turbulent flow inside heat exchanger tube fitted with cross-cut twisted tape with alternate axis (CCTA). The design parameters include the Reynolds number (5000

In this paper, an optimization procedure is presented by response surface method to optimize the temperature and velocity of drying air and thickness of the moist object inside the dryer. The optimization procedure is performed to determine the minimum drying time and energy consumption as responses. A two-dimensional (2D) numerical solution is accomplished to analyze coupled heat and mass transfer occurring during drying of an apple slice. The air flow and the moist object are solved conjugate, while the heat and mass transfer equations are solved coupled together using lattice Boltzmann method (LBM). Beside this, a sensitivity analysis is executed to calculate the sensitivity of the responses (drying time and energy consumption) to the control factors. Results reveal that the real optimized parameters for the minimum drying time and energy consumption are temperature (T = 80 °C), velocity (V = 0.10404 m/s), and thickness ratio (TR = 0.1). The results of numerical solution are compared to the experimental results, presenting a reasonable agreement. This analysis could be useful in food drying. [ABSTRACT FROM AUTHOR]

The effect of catalytic surface reaction on non-reactive flow in micro-channels is investigated. The hydraulic diameter of the channel is considered within the range of 0.2-1.2 mm, and the channel length is considered to be 5 mm. The whole length of the channel wall is coated with a catalyst. The sensitivity analysis shows that the effect of normalized hydraulic diameter is more than the normalized longitude coordinates in accordance with the existence of the large ratio of surface area to volume in the micro-channel. For validation of this model, the variation of fuel conversion is compared with the published experimental data and shows an acceptable agreement. [ABSTRACT FROM AUTHOR]

In this paper, an optimization procedure is performed by response surface methodology to optimize the position and size of the partition inside a single slope solar still. The partition is installed separately at bottom surface and glass cover of the still to improve the performance. The optimization procedure is performed to determine the maximum Nusselt number as a response. Two-dimensional steady equations with laminar assumption have been solved using a finite volume approach. Analysis is performed for a fixed value of Rayleigh number. Beside this, a sensitivity analysis is performed to calculate the sensitivity of the response (Nusselt number) to the position and size of the partition. Results show that the real optimized parameters for the maximum normalized Nusselt number of bottom installed partition are X′ = 0.23 and Y′ = 0.18. These parameters for the the maximum normalized Nusselt number of top installed partition are X′ = 0.53 and Y′ = 0.56162. Also, the installation of partition leads to an increase in vortices number with smaller sizes. Smaller vortices provide sufficient pathways to heat exchange and increase the still efficiency. [ABSTRACT FROM AUTHOR]