Design and Construction of a Tube Type Lubricating Oil Heat Exchanger (Published)
A heat exchanger is a device used to transfer thermal energy (enthalpy) between two or more fluids, at different temperatures. This tube type lubricating oil heat exchanger is used to extract heat from lubricating oil circulating in the main engine of a vessel. Its operation is based on the principle of heat balance, given as: Q=MhCph∆Th = McCpc∆Tc. This heat exchanger was designed using the Logarithmic Mean Temperature Difference method and it takes up sea water at 27 degree celsius and exits it at a temperature of 68 degree celsius. The exchanger has 96 tubes and a shell area of 0.0239 square meter, with an overall heat transfer coefficient of 172.3W/moc and effectiveness of 50.41 percent. The paper shows standard steps to design and analyze the working and performance of a Tube type heat exchanger. By plotting a graph of effectiveness against lubricating oil temperature difference, using the energy balance equation and analyzing same, the maximum possible effectiveness is obtained. The uniqueness of this design is essentially in its mode of operation, simplicity and construction.
Keywords: Construction, Design, Heat Exchanger, Tube Type Lubricating Oil
DESIGN, FABRICATION AND TESTING OF A LABORATORY SIZE HAMMER MILL (Published)
The laboratory size hammer mill was fabricated from locally available materials for crushing of minerals such as calcite, dolomite, limestone, granite and other materials of medium hardness. The crushing process is achieved by the use of a set of hammers in a crushing chamber which beats the mineral feeds into smaller particles small enough to pass through the aperture of the replaceable sieve positioned beneath the crushing chamber. The size aimed depends on the aperture of the replaceable screen. Based on the theoretical design, it was found that the main shaft speed of 913.5 rpm transmitted by a belt drive from a three horse power electric motor is suitable to crush effectively. A comparison of the products of the newly fabricated machine with those of a standard Denver laboratory jaw crusher shows that the crushing rate of the new machine is higher, though the standard machine produces coarse products. The results however indicated that the new machine can perform better in terms of products with improved design. The machine is portable, design to be power operated.
Keywords: Design, Fabrication, Laboratory Size Hammer Mill