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The objective of this paper is to introduce the notion of fractional derivatives in the energy equations and to study the chaotic nature of the temperature distribution in a heat exchanger with variation of temperature dependent transport properties. The governing fractional partial differential equations are transformed to a set of recurrence relations using fractional differential transform method and solved using inverse transform. The approximate analytical solution obtained by the proposed method has good agreement with the existing results.

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The effect of impingement cooling on the internal surface (cooling passage) of the leading edge region in a commercial turbine high pressure first stage rotor blade is investigated using Computational Fluid Dynamics (CFD) simulations. The flow domain is obtained by stretching the middle cross section (50% span) of the above mentioned blade. The simulations are performed for 3 different profiles in the cooling flow passage. In all the cases, the nozzle position and Mach number of cooling fluid is kept constant at E/D = 4.32 and 0.4 respectively. In the first case, the suction side profile is modified to facilitate shift in the vortex. This may reduce the crossflow effect, which will enhance the Nuavg. However, simulation results showed that Nuavg is reduced by 2% when compared to base case. In the second case, the coolant flow passage is smoothened at the apex to reduce dead zone and to enhance spreading of the jet. In this case, a 3% increase in Nuavg is obtained. Based on the analysis of velocity contours in the second case, the coolant flow passage in the third case is further modified to improve the spreading of flow. This resulted in 5% increase in the Nuavg when compared to base case.

The paper presents experimental data and results from a prediction tool for the performance of a desiccant loop cooling system. The experiments are performed under a variety of high humidity and hot ambient conditions and the system performance is described. One of the experimental conditions is typical of many Indian cities and the systems appropriate for those cities are established. A simulation program that can predict the performance of the desiccant loop is developed. The simulation results show that this system can work as effectively as vapor compression air-conditioning for certain ambient conditions whereas it can function as a pre-cooler to a vapor compression system under more severe conditions, resulting in a reduced power consumption. The results presented in the paper give a guideline to practicing engineers as to when a desiccant loop cooling system would be useful. A simple payback analysis and a lifecycle cost analysis shows that a desiccant cooling system with a waste heat recovery recuperator is an economically viable investment.