![Sample our Engineering & Technology journals, sign in here to start your access, latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5933/TOC-Subject-Sample-2021-Engineering-Tech.jpg"})
ABSTRACT
In this article an experimental analysis has been conducted to study the effect obstacle parameters on thermal and hydrodynamic performance of impingement jets solar air passage having protrusion with combined arc obstacles on the heated surface. The study has involved the values of Reynolds number from 4000 to 18000, relative height ratios (
) from 0.8 to 1.7, relative pitch ratios (
) from 9.0 to 12, angle of arc (
) from 40
to 80
, stream wise variation (
) from 0.39 to 0.56, and span wise variation (
) from 0.82 to 0.99, and jet diameter ratio
of 0.065 respectively. Experimental data pertinent to Nusselt number (
) and friction factor (
) were generated for various sets of roughness and flow parameters. The highest improvement is obtained at a range of
=1.1,
=10,
=60°,
=0.43,
=0.86, and
0.065 respectively. The maximum value of the thermal hydrodynamic performance was found to be 1.50 for the range of parameters investigated.
Nomenclature
| = | Orifice area, | |
| = | Surface area of heated plate, | |
| = | Area of target plate, | |
| = | Area of flow, | |
| = | Hydrodynamic diameter, | |
| = | Gap or separate distance, | |
| = | Specific heat of air, | |
| = | Obstacle height-to-duct hydrodynamic diameter ratio, dimensionless | |
| = | Relative height ratio, dimensionless | |
| = | Friction factor, dimensionless | |
| = | Height of passage, | |
| Hd/Dj | = | Height of dimple to the diameter of jet, dimensionless |
| = | Convective heat transfer coefficient, | |
| = | Jet to jet spacing, | |
| = | Length of passage, | |
| = | Jet-to-target plate distance, | |
| = | Mach number, dimensionless | |
| = | Mass flow rate of air, | |
| = | Nusselt number, dimensionless | |
| = | Relative pitch ratio, dimensionless | |
| = | Pressure reduction across orifice plate, | |
| = | Reynolds number, dimensionless | |
| = | Plate temprature of air, | |
| = | Average temprature of air, K | |
| = | Entrance temprature of air, | |
| = | Exit temprature of air, | |
| = | Velocity of air, | |
| = | Width of passage, | |
| = | Streamwise variation, dimensionless | |
| = | Spanwise variation, dimensionless | |
| SAH | = | Solar air heater |
| SAC | = | Solar air channel |
Greek letters
| = | Thermal and hydrodynamic performance, dimensionless | |
| = | Angle of arc, degree | |
| = | Density of air, kg/m3 | |
| = | Open area ratio, | |
| = | Effective efficiencies, dimensionless | |
| = | Flow-attack-angle, degree |