International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 06 Issue: 08 | Aug 2019 www.irjet.net p-ISSN: 2395-0072 © 2019, IRJET | Impact Factor value: 7.34 | ISO 9001:2008 Certified Journal | Page 1496 Experimental Investigation on Natural Convection Heat Transfer Augmentation with Vibration Effect B. Sudhakara Rao 1 , S. Ravi Babu 2 1 PG Scholar, Department of Mechanical Engineering, GMRIT, Rajam, Andhra Pradesh, India 2 Assistant Professor, Department of Power Engineering, GMRIT, Rajam, Andhra Pradesh, India ---------------------------------------------------------------------***--------------------------------------------------------------------- Abstract - The usual conventional fluids like H2O, engine oil, kerosene, ethanol, and ethylene glycol have lower thermal potential analyze to solids. Lower melting conductivity of fluid became an obstacle to use in distinctive utilization. The observations were carried out to obtain the increase in heat transfer rates as an outcome of mechanical vibrations enforced to a horizontal cylinder. The two cylindrical diameters are one in which external diameter 25cm and internal diameter is 12cm is heated inside the brass cylindrical surfaces. A Thermal layer was recognized outside the boundary layer in the ambient fluid later the study-state condition is obtain as the fluid temperature goes on increasing along an axial direction with Temperature variation of the cylinder along an axial direction. Preliminary carried out different heat inputs 30w, 40w, 50w, 60w and an interrelationship between the Nusselt numbers (Nu) for perpetual heat flux. The cylindrical surface is various vibrating frequencies 190 Hz, 160 Hz, 130 Hz, and 100 Hz. A range of amplitude, frequency, temperature difference and it is observed that amplitude length 0.5 amps. The vibration local heat transfer coefficient increases with linearly and Nusselt number increases from the bottom location to the top location. Key Words: Natural Convection, Heat Transfer, Constant Heat Flux, boundary layer, Vibration, amplitude, frequency. 1. INTRODUCTION The effect of oscillations upon the estimate of heat transfer by free convective heating surface can be studied analytically with two various methods. In this first method, a surface is taken in static and vibrations effect in the neighbouring surface in a fluid medium. In this second method, oscillation motion impacted up on surface medium itself, its escape the fluid natural conditions. In this method, the mechanical system caused by vibration at buoyant frequency and amplitude depends on it. Mechanical vibrations are used in different applications like industrial, space program and rocket propulsion motors, etc. (Martinelli and Boelter 1938) one of the earliest analyses of the vibration effect on heat transfer was done by. They studied the effect of vibrations upon the heat transfer from a horizontal tube in the water absorbed [1].The influence of vibration on the convective heat transfer which has been investigated in the past studies for cylinders, flat plate, and other geometries and has carried out for different directions of applied vibration relative to these surfaces and various ranges of applied frequency and amplitude and different thermal boundary conditions. The results of these investigations show that the vibration gives a large increase to none increase or even a decrease in the heat transfer rate [2]. One of the practical problems, which originally inspired interest in the effect of vibration on heat transfer, was encountered in rocket propulsion motors. As combustion instability of high amplitude occurred in such motors, the local heat transfer to the motor walls drastically increased and the wall temperature rose to the point where the motor was destroyed. The vibrating either the surface of the liquid contents of an extraction column to improve its efficiency. This is the principle of pulsed columns which is widely applied in the nuclear field [3].Abdel amid R. S. performs an experimental study for the effect of forced vertical vibrations on free convection heat transfer coefficient, from a flat plate made of aluminum with dimension (300 mm length, 100 mm width, and 3 mm thickness). It has been heated under a constant heat flux of (250-1500 W/m2) in an upward direction. The flat plate was located horizontally or inclined in multiple angles at a range of (0 o , 30 o , 45 o , 60 o , 90 o ). The experimental study is carried out at a range of frequency (2-16 Hz) and the amplitude at the range of (1.63-7.16 mm). The results of this study show that the relation between the heat transfer coefficient and the amplitude of vibration is incrementally for inclination angles from (0 o , 30 o , 45 o , 60 o , 90 o ), and reaches a maximum ratio of (13.3%) in the horizontal state, except at the vertical state (θ = 90 o ) the heat transfer coefficient decreases as the excitation increases and the maximum decrease ratio occurs at (7.65 %) [4].In the current study, a detailed effort has been under taken to develop correlations for heat transfer from a cylinder in a low-amplitude zero-mean oscillatory flow. The cylinder is representative of a heat exchanger tube while the oscillatory flow is typical of the acoustic field in a thermo acoustic engine. The low- amplitude feature refers to oscillatory flow displacement amplitudes being small on the scale of the characteristic body dimension, i.e. the cylinder diameter. The various dimensionless parameters of importance in this range have been identified and systematically covered [5].Besides acoustic streaming, other acoustic mechanisms can transport heat. Greatly enhanced heat transport down a temperature gradient can be obtained using large amplitude oscillating flows without recourse to the streaming effect. The large particle velocity creates a thin boundary layer between the bulk of the fluid and an adjacent wall containing a large temperature gradient normal to the wall. Because the fluid and wall temperatures differ substantially, and because the boundary layer is thin, enormous radial heats flux results. On opposite halves of the