A COMPARATIVE STUDY OF FLOW AND HEAT TRANSFER CHARACTERISTICS OF STAGGERED AND IN-LINE CROSS-FLOW TUBE-TYPE HEAT EXCHANGERS, PART II: THE FINITE ELEMENT ANALYSIS

Numerical analysis of fluid flow and heat transfer were performed for cross-flow tube-type heat exchanger in staggered and in-line arrangement. The purpose of this project was to simulate the process of forced convection heat transfer of air over a heated cylindrical pure copper rod using finite element scheme and compared the results with experimentally obtained data. Also, the work was to compare the performance of both staggered and in-line tube bundle configurations. The cross-flow tube-type heat exchangers consist of 25 mm transverse pitch, 18.75 mm longitudinal pitch, 20 cylindrical rods of Ø12.5 mm in a 125 x 125 mm cross section. Finite element simulation was carried out by modeling the working sections of the cross flow heat exchangers. In this, Model geometry was created, meshed, calculated, and post-processed using FEMLAB 3.0 for ten different air inlet velocities corresponding to experimental data obtained. The simulation results revealed 29.77% and 25.31% deviation in Nusselt number from experimental results for staggered and in-line tube bank respectivel

Wind Energy Systems for Omu Aran, Kwara State, Nigeria

The quest for energy from renewable and sustainable sources has led to the investment on exploration and installations of wind energy systems to harness energy from wind for use by mankind. Various wind energy systems exist and they are quite expensive. Selections of appropriate systems for installation are dependent on the wind power available in a location. It is therefore important that proper wind assessment is done before investments on infrastructures for harnessing wind power are put in place. Wind data between 2014 and 2018 were obtained from the Landmark University Weather Station in Omu Aran and the pattern of wind speed distribution in the location over the years in focus were determined by the Weibull function. The power law was used to estimate the wind speeds at heights of 10 and 20 metres respectively. Recommendations on appropriate wind energy systems suitable for Omu Aran region were made based on the wind speed pattern

Experimental Comparison of Staggered and In-line Tube-bank Thermal Performance.

Experimental investigation of fluid flow and heat transfer were performed for cross-flow tube-type heat exchanger in staggered and in-line arrangement. The purpose of this work was to determine the process of forced convection heat transfer of air over a heated cylindrical pure copper rod. Also, the work was to compare the performance of both staggered and in-line tube bundle configurations. Tube bank with staggered arrangement consisted of 25 mm transverse pitch, 18.75 mm longitudinal pitch, 20 cylindrical rods of diameter12.5 mm, in a 125 x 125 mm cross section. An in-line tube arrangement was constructed based on the staggered tube bank dimensions. During the test, the working sections were placed one after the other in a specially design testing rig air channel through which the fluid flowed normal to the tube. A complete set of test were taken with the heated element in each of the four banks of tube for ten different throttle openings in the range of 10 to 100%. The test results show that the heat transfer coefficient associated with the tube is a function of its position in the tube bank. Higher heat transfer coefficients were obtained in the subsequent tube bank downstream of the first row. However, the heat transfer coefficients stabilize, such that little change occurs for tube beyond the fourth row. The overall heat transfer coefficient for staggered tube arrangement was found to be 4.28% higher than of the in-line tube arrangement

PROMOTING ECO-FRIENDLY CORROSION INHIBITOR USING BITTER KOLA LEAVES IN CARBON MILD STEEL USING HCLACIDIC MEDIA

Corrosion of mild steel in HCl was investigated using the weight loss method. The mild steel used was cut into 16 coupons with 5.0 cm x 5.0 cm x 0.2 cm dimensions which weredegreased with ethanol and washed with distilled water and finally weighed. The mild steel coupons were exposed to HCl with varied concentrations (0, 10, 25 and 40%) of Garcinia kola extracts used as corrosion inhibitors for 4 hours at 400C and 600C respectively. The result showed that at 400C; the inhibition efficiency of 65.5% was observed at 25 % HCl concentration and 62.9% at 40% HCl concentration while at 600C; inhibition efficiency of 87.7% was at 25% HCl concentration and 88.1% at 40% concentration respectively. It can be concluded that increase in concentration increases the inhibition efficiency. The presence of flavonoid and alkanoids in bitter kola stem is a good inhibito

Stand-alone wind energy systems for power generation in Nigeria

The realization of a stable and adequate electricity generation and supply has been a serious challenge in Nigeria, especially in the remote areas of the country. The interest of the government and private firms has been on the installation of power plant running on fossil fuel while neglecting the renewable energy resources the country is endowed with. To achieve adequate generation and supply of electricity to the populace in urban and remote areas, appropriate stand-alone wind energy systems are recommended for installation in wind sites, on buildings and communication masts based on the wind pattern of the various locations in the country. A brief review of the wind potentials of the various locations in the country is done. A review on the HAWT and the various configurations of the VAWT is done with emphasis on its merits and demerits and also a brief review on building-mounted wind power systems is done, with recommendations on appropriate wind energy systems for installation

Influence of Commercial Gasoline Samples on the Performance Characteristics of SI Engines

It has been observed though not documented that some gas filling stations in Nigeria adulterate their fuel before selling to customers. Numerous engine users had also complained of fuel obtained from some petrol filling stations burn faster than others. Engines used in automobile vehicles and power plants always developed one fault or the other leading to frequent visit to mechanics. In view of these preceding issues, experimental study was conducted to determine the influence of gasoline sold in Nigeria market on engine performance characteristics. Four samples of commercial gasoline were collected from different petrol stations within Omu-Aran metropolis, Kwara State, Nigeria and tested on a four stroke single cylinder spark ignition engine (P8161) automotive test bed at wide throttle opening. However, the octane rating of the selected fuel samples could not be ascertain because gasoline supplied at Nigeria petrol stations are no longer rated as it used to be as regular, premium and regular unleaded. The results of this investigation show that the performance parameters such as torque, brake power, brake mean effective pressure and thermal efficiency for each fuel sample increase with increase engine speed up to a maximum value and begin to decrease as engine speed increase due to frictional loss. Maximum brake power obtained with fuel sample A was 5.751 kW at 3083 rpm. For fuel sample B, the maximum brake power was 5.025kW at 2884 rpm, 5.269 kW at 2727 for fuel sample C and 5.019 kW at 2718 rpm for fuel sample D. From this test, brake maximum power and torque occur at the same engine speed for each sample of fuel sample studied. Also the maximum power obtained from fuel sample B and D were approximately the same at different engine speed. It may suffice to say that fuel sample B and D were likely supplied to the different petrol filling stations by the same source. The minimum amount of fuel consumed in order to attain maximum power was more with fuel sample D and B corresponding to 36.73 g/kW.hr and 36.63 g/kW.hr respectively. The minimum brake specific fuel consumption was lower for fuel sample A and C with value 32.21 g/kW.hr and 35.44 g/kW.hr respectively. Therefore, it is more economical and reliable to run spark ignition engines with fuel sample A and C. Analysis of fuel variability shows that the coefficient of variation in engine speed for fuel sample A, B, C and D were 32.6%, 34.2%, 33.1% and 35.2% respectively. In terms of brake power developed the coefficients of variation were 52.2%, 56%, 53.8% and 60.6% for fuels A, B, C and D respectively. The coefficient of variation in terms brake specific fuel consumption are 101.3%, 142.8%, 111.5% and 131.9% for fuel samples A, B, C and D respectively. It means that more of fuel B was consumed follow by fuel sample D during the combustions process compared to fuel samples A and C. For fuel sample B approximately 43% additional fuel is required to attain the maximum power and about 32% of fuel sample D. Approximately 12% additional of fuel sample C is required while only 2% of fuel sample A is needed. From the results fuel sample A is more reliable for achieving engine performance specifications follow by fuel sample C and B while fuel sample D is less reliable. One of the factors that may be responsible for the variation is fuel octane rating which is a measure of how smooth an engine runs or resistance to knocking. If this is true, engines running on fuel samples D and B are more prone to pre-ignition or engine knock than fuel sample A and C. It then means there is strong relationship between fuel samples and engine performance

The Role Of Tire In Car Crash, Its Causes, And Prevention

This paper looked at the role that tires play in car crash. In the course of our study, we analyzed various causes of tire related car crash which includes; tire pressure (under-inflation and over-inflation) and abnormal wears. Bad inflation pressure of tires, either under-inflation or over-inflation causes tires to wear easily and increases poor vehicle handling by drivers. The solution to the crashes originating from tire was also outlined; inflating the tire with its recommended inflation, using good tires that are not up to six years from the date of manufacture and also the use of tires with good tread will prevent tire related car crash. Keywords---Tire, car crash, inflation, prevention, wear, thread

Combustion Enhancers in Diesel Engines: Magnetic Field Option

Particulate Matter (PM) is one of the major harmful substances in diesel exhaust gas. Technologies like the Diesel Particulate Filter (DPF) and Diesel Oxidation Catalyst (DOC) have been positioned at the exhaust to reduce the quantity of harmful substances released to the environment. This paper highlights the factors that affect combustion in diesel engines and the potential of the introduction of electromagnetic field in the combustion chamber on the improvement of the diesel engine efficiency and reduction in the quantity of Particulate Matter (PM) produced. Keywords: Magnetic Field, Diesel Fuel, Sauter Mean Diameter, Viscosity, Combustion

Electricity Stability in Nigeria Through Increased Hydro Power Generation

Slow response to generation and delivery of stable electricity in Nigeria, poses as a problem to development of the country. Industries and residential homes in the country now use generating set as an alternative due to instability in electricity supply. To reduce problem of power outages in Nigeria through renewable sources of energy, hydro power stands as one option to meet the growing demand of electricity because of presence of many rivers with hydro potentials. Keywords----Electricity, Hydropower, Power outage, Renewabl