Heat and Fluid Flow Characteristics of Inside Conical Ring Obstacles in an Impinging Jet Solar Air Heater

Abstract

newline xi newlineABSTRACT newlineIn this work, the experimental analysis on flow and heat transfer characteristics of different types of impingement jet plates is performed. The various air jet impingement plates such as, triangular shape air jets impingement plate, rectangular shape air jets impingement plate, square shape air jet impingement plate, circular shape air jets impingement plate have been analyzed for the same Reynolds number. The hydrodynamic and thermal performance is discussed to examine the overall effects of the various shapes of impingement jet plates. The results reveal that the circular impingement jet shapes provide better hydrodynamic and thermal performance than other comparable impingement jet shapes. The highest absolute data of (and#119873;and#119906;/and#119873;and#119906;and#119904;and#119904;)/(and#119891;/and#119891;and#119904;and#119904;)0.33 has been observed to be 1.59 corresponding to relative impingement jet diameter (and#119863;and#119868;and#119869;/and#119863;and#119867;) of 0.055, relative X-axis jet distance (and#119883;and#119894;and#119898;and#119901;/and#119863;and#119867;) of 0.366 and relative Y-axis jet distance (and#119884;and#119894;and#119898;and#119901;/and#119863;and#119867;) of 0.311. newlineThis thesis work deals with the experimental and numerical study with inside conical obstacles used on the underside of the absorber plate with round jets impingement in a solar air rectangular passage. Turbulent convection of fluid flow through the impingement round jets solar air rectangular passage with inside conical ring obstacle shapes are studied experimentally. The testing of impingement round jets solar air rectangular passage contains; relative inside conical ring height (and#119867;and#119877;/and#119863;and#119867;) lies from 0.073-0.128, ratio of inlet flow diameter to inner print diameter of ring (and#119863;and#119868;and#119877;/and#119863;and#119861;and#119877;) lies from 1.3-2.3, ratio of ring diameter to ring height (and#119863;and#119874;/and#119867;and#119877;) lies from 1.67-2.67, relative X-axis pitch (and#119883;and#119878;/and#119863;and#119874;) lies from 4.71-7.71, relative Y-axis pitch (and#119884;and#119878;/and#119863;and#119874;) lies from 2.92-5.14, relative impingement round jets diameter (and#119863;and#119868;and#119869;/and#119863;and#119867;) and Reynolds number (Re) of flow was varied between 5,000 to 23,000. The fixed values of relative impingement round jets diameter (and#119863;and#119868;and#119869;/and#119863;and#119867;) of 0.366, relative X-axis jet distance (and#119883;and#119894;and#119898;and#119901;/and#119863;and#119867;) of 0.366 and relative Y-axis jet distance (and#119884;and#119894;and#119898;and#119901;/and#119863;and#119867;) of 0.311. Experimental analysis has been carried out to determine the hydrodynamic and thermal performance of impingement round jets solar air heater with inside conical ring obstacles on the heated wall for the turbulent regime under a uniform heat flux. The highest value of hydrodynamic and thermal performance is observed at and#119867;and#119877;/and#119863;and#119867; of 0.110, and#119863;and#119868;and#119877;/and#119863;and#119861;and#119877; of 1.7, and#119863;and#119874;/and#119867;and#119877; of 2.33, and#119883;and#119878;/and#119863;and#119874; of 5.28, and#119884;and#119878;/and#119863;and#119874; of 3.42, and#119863;and#119868;and#119869;/and#119863;and#119867; of 0.055, and#119883;and#119894;and#119898;and#119901;/and#119863;and#119867; of 0.366, and and#119884;and#119894;and#119898;and#119901;/and#119863;and#119867; of newlinexii newline0.311. The extreme value of the hydrodynamic and thermal performance was found to be 2.16 for the range of parameters examined. newlineThe statistical correlations of Nusselt number and friction factor are also developed from the experimental results of inside conical ring obstacles in round jets impingement solar air rectangular passage, which can be used to predict the values of Nusselt number and friction factor with considerably good accuracy. A deviation of experimental and predicted values of the and#119873;and#119906;and#119874;and#119878; and and#119891;and#119874;and#119878; comes out to be ±11.2% and ±10.8%; respectively. These results show an acceptable agreement between the experimental and the predicted values of and#119873;and#119906;and#119874;and#119878; and and#119891;and#119874;and#119878;. newlineFurther, the optimization of performance of solar air heater has been carried out on the basis of exergetic efficiency criterion as a function of Reynolds number and temperature rise parameter at fixed value of solar intensity (and#119868;=1000and#119882;/and#119898;2). The exergetic efficiency (and#120578;and#119890;and#119909;and#119892;) of SAH with jet impingement and inside conical ring obstacles on absorber plate is calculated by considering the different range of system design and operating parameters. At the end, the design plots for optimum inside conical ring roughness parameter has been plotted on the basis of exergetic efficiency criterion at different values of solar intensity (and#119868;).