Forced Convection Heat Transfer Analysis of Square Shaped Dimples on Flat Plates
Jamil Ahmed,
Hasibur Rahman Sardar,
Abdul Razak Kaladgi
Issue:
Volume 3, Issue 5, September 2015
Pages:
66-70
Received:
24 May 2015
Accepted:
29 June 2015
Published:
10 August 2015
Abstract: Dimples play a very important role in heat transfer enhancement of electronic cooling systems. This work mainly deals with experimental investigation of forced convection heat transfer over square shaped dimples on a flat aluminum plate under external laminar flow conditions. Experimental measurements on heat transfer rate and friction characteristics of air (with various inlet flow rates) on a flat plate were conducted. Both staggered and inline arrangements of the dimples were considered for the analysis. From the obtained results, it has been observed that the heat transfer coefficient were high for the plate having dimples.
Abstract: Dimples play a very important role in heat transfer enhancement of electronic cooling systems. This work mainly deals with experimental investigation of forced convection heat transfer over square shaped dimples on a flat aluminum plate under external laminar flow conditions. Experimental measurements on heat transfer rate and friction characterist...
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Combustion Characteristics and Energy Potential of Municipal Solid Waste in Arusha City, Tanzania
Halidini Sarakikya,
Jeremiah Kiplagat
Issue:
Volume 3, Issue 5, September 2015
Pages:
71-77
Received:
7 August 2015
Accepted:
21 August 2015
Published:
2 September 2015
Abstract: Municipal Solid Waste (MSW) generation has been increasing due to population growth, changing life style, technology development and increased consumption of goods. The increase of waste generation combined with the use of waste dumps may lead to environmental and social problems such as water contamination, land and atmospheric pollutions, resulting to breeding grounds for vermin, cause risk of fire, bad smell and potentially are the cause of illness. Energy recovery from municipal solid waste can alleviate these problems while providing a source of energy. The objective of this study is to evaluate the combustion properties and energy potential from municipal solid waste of Arusha, Tanzania. Incineration is among the methods for MSW treatments, and therefore, the data and information provided shows that energy can be recovered from Arusha MSW during incineration process. Energy flow (exothermic and endothermic) and thermal degradation analysis were carried out using Differential Scanning Calorimetry (DSC) and thermo – gravimetric analysis (TGA) respectively. The sample of composition of municipal solid waste examined included paper, cardboard, wood, textile, rubber, polyethylene Teraphthalate (PETE), low density polyethylene (LDPE) and food waste. These materials were heated in a combined DSC and TGA analyser and experiments were performed at heating rate of 10○C/min, in a pure nitrogen atmosphere at temperatures between room temperature and 1100 ○C. The results observed from TGA and DTG show that the highest reactivity was the samples from Central Market, followed by those from Sakina and Ngarenaro market. It was observed that municipal solid waste is less reactive to combustion compared to dry biomass, thus its reactivity can be improved by removing non- combustible materials such as metals and food scraps or by pre-treating the MSW so as to reduce the amount of oxygen present in it. The final analysis of the municipal solid waste showed that, the average percentage of nitrogen, sulfur, chlorine and phosphorus in the waste were 2.36%, 0.37%, 0.04% and 0.11% respectively, which is low and therefore, emissions released by this MSW during combustion are also low. The energy content of the solid waste tested was about 12MJ/kg on dry basis. The elemental composition shows that municipal solid waste contains 50% and 5% of carbon and hydrogen respectively.
Abstract: Municipal Solid Waste (MSW) generation has been increasing due to population growth, changing life style, technology development and increased consumption of goods. The increase of waste generation combined with the use of waste dumps may lead to environmental and social problems such as water contamination, land and atmospheric pollutions, resulti...
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