Experimental flow visualization and performance analysis of horizontal water-air ejector system

Muhammad Penta Helios*, Wanchai Asvapoositkul and Kyung Chun Kim

<p style="text-align:justify;"><strong>Abstract:</strong> This paper presented an experimental study of water-air two-phase flow in the throat-diffuser region of a horizontal ejector. The aims are to visualize flow patterns and to assess the performance of ejector at different backpressure. The performance was described into dimensionless terms, i.e., the pressure ratio and volumetric ratio. The ejector operated at a constant water flow rate and six different back pressure as the operating condition. Both non-intrusive and intrusive methods were applied to visualize the flow and to record related data of performance, i.e., flow rate, pressure, and temperature simultaneously. An image processing algorithm and performance analysis were employed simultaneously to analyze the images, while sensor data recording was used to evaluate the ejector's performance. The results revealed that the two flow patterns appeared with increasing of backpressure, namely the stratified-wavy and bubbly flows. The binary image exposed that the highest performance of the ejector obtained when the bubble generation and mixing process happened at the middle and end section of the throat, respectively. As the mixing process results, the highest area gas fraction and performance increased with increasing backpressure ratio. It indicated intimate air dispersed in water occurs pointed by declining of the volumetric ratio.<br /></p><p><strong>Keywords: </strong>High-speed camera, stratified-wavy flow, bubbly flow, mixing process, ejector performance.</p>

Life cycle cost analysis of ethanol production from sugarcane molasses for gasoline substitution as transportation fuel in Pakistan

Ahsan Farooq, Athikom Bangviwat and Shabbir H. Gheewala

<p style="text-align:justify;"><strong>Abstract:</strong> The transportation sector is growing rapidly in a developing country like Pakistan and it mostly depends on imported petroleum products. To substitute these limited and environment-offending fuels with renewable and more sustainable fuels, ethanol has been recognized as one of the possible solutions. However, the economic competitiveness of ethanol against gasoline must be investigated to ensure its economic sustainability. The present study has adopted a life cycle costing approach for the economic analysis of sugarcane molasses-based ethanol production. The economic feasibility of gasoline substitution by molasses-based ethanol in the form of gasoline-ethanol blends E10 and E20 (10% and 20% blends of ethanol with gasoline, respectively) has been explored. The results of cost breakdown analysis showed that the net feedstock cost had the highest contribution followed by operation and maintenance cost, and capital investment cost respectively, in the estimated ethanol production cost. Both blends showed comparative economic advantages over gasoline in terms of energy production. It is concluded that E20 is the better option because of its lower production cost, better environmental performance and the potential to bring better social reforms as compared to E10.<br /></p><p><strong>Keywords:</strong> Life cycle costing, Molasses, Ethanol, Gasoline, Pakistan.</p>