Influence of the non-equal aligned nozzles for fuel injection inside the supersonic combustion chamber.

The importance of fuel mixing for the progress of the scramjet engine is indisputable. The present article shows the importance of the non-equal multi-injector system for effective fuel distribution and flame holding inside the combustion segment of a scramjet engine. The supersonic air and fuel jet flow in the non-equal nozzle arrangement is simulated via computational fluid dynamic technique. Two injector types of circular and rectangular nozzle have been analyzed to attain flow characteristics of hydrogen jets at supersonic cross flow. Mach contour is also analyzed for these jet arrangements to show the interface of the jet in the non-equal jet arrangement. Besides, addition of internal air jet is also simulated and evaluated in this research. Our investigation shows that the diffusion height of the fuel jet is higher when a rectangular non-equal nozzle is applied. The circular nozzle is more active in the spreading of the fuel in the combustor and the use of an internal air jet effectively increases fuel in a combustor of the scramjet.

Thermal performance augmentation in a pipe employing hybrid nanofluid and a plate as turbulator with V-shaped double-winglet ribs.

This article employs a plate with V-shape ribs inside a tube as turbulator to augment the heat transfer rate. The utilized vortex generators are double-winglets arranged in a V-shape placed on both sides of the plate. The proposed system's suggested working fluids are water-based hybrid nanofluids, including Al2O3-Cu/water, Cu-CuO/water, and Cu-TiO2/water. This work involves a numerical evaluation of the effects of the type and volume concentration of the examined hybrid nanofluids on the enhancement of heat transfer. The experimental results are used to validate the numerical model. It is worth mentioning that all the obtained numerical results are compared with the simple tube, without any turbulator (vortex generator) and in the presence of water instead of the hybrid nanofluids. Based on the numerical results, it can be concluded that all employed hybrid nanofluids showed improved thermal performance compared to pure water. Furthermore, the differences between the models are more substantial for higher Reynolds numbers than for lower Reynolds numbers. In Re = 30,000, the Cu-TiO2/water exhibits the lowest thermal performance improvement (augmentation of about 0.3%), while the Cu-CuO/water at Re = 50,000 exhibits the largest thermal performance improvement (augmentation of approximately 5.7%), in the case of ∅1 = ∅2 = 0.5%. For ∅1 = ∅2 = 1%, the Cu-TiO2/water at Re = 30,000 has the lowest thermal performance improvement (augmentation of around 1.1%), while the Cu-CuO/water at Re = 50,000 has the most thermal performance improvement (augmentation of roughly 8.7%). According to the augmentation of around 2.8% at Re = 30,000 for Cu-TiO2/water and approximately 10.8% at Re = 50,000 for Cu-CuO/water, the thermal performance increase in the scenario of ∅1 = ∅2 = 1.5% is the lowest. In Conclusion, the Cu-CuO/water hybrid nanofluid with a volume concentration of ∅1 = ∅2 = 1.5% has the greatest thermal performance value of all the hybrid nanofluids studied.