Devdatta P. Kulkarni

Convective Heat Transfer and Fluid Dynamic Characteristics of SiO2 Ethylene Glycol/Water Nanofluid

Nanofluids comprised of silicon dioxide (SiO2) nanoparticles suspended in a 60:40 (% by weight) ethylene glycol and water (EG/water) mixture were investigated for their heat transfer and fluid dynamic performance. First, the rheological properties of different volume percents of SiO2 nanofluids were investigated at varying temperatures. The effect of particle diameter (20 nm, 50 nm, 100 nm) on the viscosity of the fluid was investigated. Subsequent experiments were performed to investigate the convective heat transfer enhancement of nanofluids in the turbulent regime by using the viscosity values measured. The experimental system was first tested with EG/water mixture to establish agreement with the Dittus-Boelter equation for Nusselt number and with Blasius equation for friction factor. The increase in heat transfer coefficient due to nanofluids for various volume concentrations has been presented. Pressure loss was observed to increase with nanoparticle volume concentration. It was observed that an increase in particle diameter increased the heat transfer coefficient. Typical percentage increases of heat transfer coefficient and pressure loss at fixed Reynolds number are presented.

Design, construction and testing of a low‐cost hybrid rocket motor

Small hybrid rocket motors using solid propellant and gaseous oxidizer are becoming increasingly popular as a propulsion device. This paper describes the development of a one‐dimensional flow model for the design of a small rocket motor. Combustion of polyethylene as solid propellant with oxygen is used as a candidate hybrid fuel to test and evaluate the performance of this hybrid system. To assess the performance under different operating conditions, a computer program has been developed, which facilitates inputs to be varied and effects assessed. A system of governing equations is summarized in the main body of this paper and is numerically solved by the computer program. The results of the modelling are then used to design and build a small low‐cost rocket motor for experimental verification. Therefore, the materials presented herein could be used in the future design of hybrid rocket motors.

Thermal Properties of Petroleum and Gas-to-liquid Products

Abstract There are many locations in the world where natural gas is abundant, but isolated from the transportation infrastructure. Research is currently underway to develop methods to convert the gas to liquid (GTL) and transport it to the market. For safe and efficient transportation of this GTL, researchers and engineers must know its properties. This article presents several correlations for viscosity, specific heat, and thermal conductivity of this GTL. Researchers are also considering transportation of GTL commingled with crude oil. Therefore, the properties of this commingled mixture are presented here as well. Data on how these properties vary with temperature is also presented in graphs; this information would be very useful for designing a method of transportation in extremely cold regions.

Analysis of Pressure Loss and Heat Transfer of Non-Newtonian Fluid Flow through Trans-Alaska Pipeline System

Abstract In this study, theoretical analyses have been performed to determine the feasibility of transporting gas-to-liquid (GTL) products through the Trans-Alaska Pipeline System (TAPS) using a non-Newtonian fluid flow approach. Due to heat loss, the fluid temperature decreases in the direction of flow, and this affects the fluid properties, which in turn influence the convection coefficient and pumping power requirements. This article presents fluid temperature and heat loss along the pipeline at different locations. Furthermore, this study includes calculations on the power required to pump GTL and crude oil/GTL mix. Parametric studies had been performed varying two parameters: wind velocity, to vary convection over the pipeline, and snow depth. Ambient air velocities of 0.45 m/s (1 mph), 4.47 m/s (10 mph), and 8.94 m/s (20 mph) have been considered. Snow depths of 0 m (0 ft), 0.305 m (1 ft), and 0.61 m (2 ft) have also been taken into account. These results show that the pumping power and heat loss for GTL and commingled mixtures are less than that predicted by Nerellas (2002) Newtonian flow calculations.