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Enhancement of heat removal and reduction of fin size become a major concern in designing heat exchanger equipment. The present paper reports an experimental analysis to investigate the turbulent heat transfer performance of rectangular fin arrays, both solid and circular perforations along the length of the fins. The size and number of circular perforation have been varied. Tests have been conducted in a horizontal wind tunnel equipped with forced draft fan. The data are obtained by varying flow velocities while maintaining constant heat input and taken over a period of time. The Reynolds number is varied between 6 × 10 4 through 25 × 10 4 . The heat loss due to radiation and convection is taken into account during calculation. Thermal performances and effectiveness of perforation and equivalent surface solid fin arrays have been evaluated and compared. Results show remarkable heat transfer enhancement, lower thermal resistances, pressure drop and higher efficiencies, effectiveness for perforated fins with increasing number of perforations in addition to the considerable reduction in weight in comparison with solid fin arrays.

In this research work, an experimental investigation of wind effect on hexagonal cylinder was carried out. The study was performed on the single cylinder. The test was conducted in an open circuit wind tunnel at a Reynolds number of 4.22 x 10 4 based on the face width of the cylinder across the flow direction in a uniform flow velocity of 13.5 m/s. The test was carried out at various angles of attack from 0° to 50° at a step of 10°. The surface static pressures at the different locations of the cylinder were measured with the help of inclined multi-manometers. The wind velocity was kept constant at 13.5 m/s. The pressure coefficients were calculated from the measured values of the surface static pressure distribution on the cylinder. Later the drag and lift coefficients were obtained from the pressure coefficients by the numerical integration method. The results will enable the engineers and architects to design buildings more efficiently. Since the results will be expressed in the non-dimensional form they may be applied for the prototype building.

In the present study, mixed convection heat transfer inside a square cavity filled with Cu-water nanofluid has been investigated numerically. The bottom wall of the cavity is maintained at a constant high temperature while the vertical sidewalls are assumed to be at a constant low temperature. The top wall of the cavity is insulated and moving at a constant velocity. Galerkin finite element method has been employed to solve the continuity, momentum and energy balance equations for the present problem. Analysis of thermal and flow fields inside the cavity has been analysed in terms of isotherms, streamlines and heatlines for a wide range of the Richardson number and solid volume fraction of the nanoparticle. Particular attention was paid to the case of pure mixed convection case with the Richardson No being equal to 1 for various combinations of natural convection and forced convection effects. The heat transfer performance of the system has been analysed in terms of average Nusselt number over the heated wall for various parameters. The present study shows that the distribution of streamline, isothermal lines and heatlines are very sensitive to Richardson number. The present study also shows that larger heat transfer rates can be achieved with nanofluid than the base fluid for all conditions.

This paper explains the fabrication of an UAV having aerofoil shaped fuselage using NACA 4416 profile and compare the result between the aerodynamic characteristics with that of the same model obtained from CFD investigation. Open circuit subsonic wind tunnel has been used to test the fabricated UAV model and collection of data. The wind tunnel is associated with Versatile Data Acquisition System (VDAS) to measure the lift & drag force coefficients and point surface pressures. This paper explains the design parameters and investigation of the aerodynamic characteristics of the fabricated ‘Aerofoil Shaped Fuselage’ UAV model. This type of model might be used for many military and civil applications like scientific data gathering, surveillance for law enforcement & homeland security, precision agriculture, forest fire monitoring, geological survey etc. The aerodynamic characteristics of Aerofoil Shaped Fuselage UAV model have been carried out at two different Reynolds Number (1.37 x 10 5 and 2.74 x 10 5 respectively) with different angles of attack from -3 o to 18 o . The stalling angle of this design is found at about 14 o during experimental investigation. The aerofoil shaped fuselage UAV model might be used for designing the future UAV.

In this research work, an experimental investigation of wind effect on pentagonal and hexagonal staggered cylinders was carried out. The study was performed on the group consisting of three cylinders, arranged in staggered form, one pentagonal cylinder in the upstream and another two hexagonal cylinder in the downstream side. The test was conducted in an open circuit wind tunnel at a Reynolds number of 4.22 x 10 4 based on the face width of the cylinder across the flow direction in a uniform flow velocity of 13.5 m/s. The group of three cylinders was taken into consideration for the study and the surface static pressures were measured for various transverse spacing of 2D, 3D, 5D and longitudinal spacing of 1D, 2D, 4D, 6D, 8D, where D is the width of the cylinder across the flow direction. The surface static pressures at the different locations of the cylinder were measured with the help of inclined multi-manometers. The pressure coefficients were calculated from the measured values of the surface static pressure distribution on the cylinder. Later the drag and lift coefficients were obtained from the pressure coefficients by the numerical integration method. The results will enable the engineers and architects to design buildings more efficiently. Since the results will be expressed in the non-dimensional form they may be applied for the prototype building.

At present Closed Loop Pulsating Heat Pipe (CLPHP) is a novel cooling strategy for successful thermal management though it is a complex heat transfer device having a strong thermo-hydrodynamic coupling to govern the thermal performance. This research is to study the effect of inclination angle and working fluid on the heat transfer characteristics and performance of CLPHP. The performance characterization has been done using two different working fluids of water and ethanol with inclination angle of 0˚ (vertical), 30˚, 45˚, 60˚, 75˚ and 90˚ (horizontal). The experiment is conducted on a CLPHP made of 148 cm long copper capillary tube of 3.0 mm outer diameter and 2.0 mm inner diameter creating a total of 13 turns. The total length of evaporator section is 39.5 cm and condenser section is 31.5 cm; while the rest is assumed to be adiabatic. The evaporator section is heated by electrical heat input, while the condenser section is cooled by atmospheric air flow. Since a PHP is recognized as a two phase heat transfer device, for comparative studies it is operated as a double-phase system by filling it 70% with the working fluid. The comparative study results in a better understanding of the underlying physics of the PHP operation. The experimental results indicate a strong influence of gravity and thermo physical properties of the working fluid on the performance of the CLPHP. The results demonstrate the effect of the input heat flux, inclination angle and physiochemical properties of the working fluid on the thermal performance of the device.