Experimental and numerical study of turbulent fluid flow of jet impingement on a solid block in a confined duct with baffles

This study investigates the heat transfer and fluid flow characteristics of turbulent flow resulting from jet impingement on a heated solid block positioned on the lower wall of a duct with baffles. Both experimental and numerical methods were employed in this research. The flow was presumed to be three-dimensional, steady, incompressible, and turbulent. The study involved the installation of one baffle on the lower wall and another one on the upper wall. Three variants of the k-epsilon turbulence model (the standard, the RNG, and the realizable) were numerically compared. The realizable k-epsilon model has shown the most reliable results compared to the other models, and thus is utilized in all calculations. The flow characteristics were experimentally and numerically studied by varying jet Reynolds number (38,957 <= Re <= 77,315), baffle height (hb /d = 0.6,0.8 and 1.0), baffles' locations arrangement [(L1/d with L2/d) as (3 with 4), (4 with 6), (6 with 8) and (6 with 4)], solid block temperature (333 o K <= Tb <= 363 o K) at an aspect ratio (w/a) of 5.25. The results showed that several vortices were formed: a main vortex close to the upper wall, a smaller one above the hot solid block, a vortex adjacent to the solid block, and additional vortex zones both in front of and behind the lower and upper baffles. The vortices intensity increases as the Reynolds number grows up. When the baffle locations change downstream, the sizes of these generated vortices increase, the height of the recirculation zone behind the lower baffle is slightly higher than that behind the upper baffle, and the primary vortex diminishes. Besides, all recirculation zones grow up in sizes when swapping the baffle locations. The study also revealed that the pressure is higher when the baffle is presented in the domain than the case of no baffle. The pressure value at the stagnation point, peak sub-atmospheric pressure value and maximum pressure value increase as the Reynolds number increases. They also increase with the increase of baffle height. However, it was found that the pressure values decay when the positions of the baffles get changed in the downstream direction. In addition, the results showed that the maximum deviation in temperature between the experimental and theoretical results was about 3 %. Besides, the increase in the maximum temperature value in the presence of baffles was about 10.8 % as compared to the case without baffles. Furthermore, the temperature increases as the Reynolds number decreases while it increases with the increase of solid block temperature and/or baffles height and location.