Bodius Salam

Performance of Turbulent Flow Heat Transfer Through a Tube With Perforated Strip Inserts

An experimental study was conducted to evaluate the performance of heat transfer for turbulent flow through a tube using air as the working fluid with perforated rectangular strip inserts. Mild steel rectangular strips of different pore diameters 2.1, 3.2, 4.25, 5.3, and 7.42 mm with corresponding porosities of 1.1%, 2.5%, 4.4%, 6.8%, and 13.3%, respectively, were used in the flow field. Heat transfer and pressure drop data were taken for Reynolds numbers ranging from 14,000 to 47,000. The experimental results showed that the Nusselt number, heat exchanger effectiveness, and friction factor were higher than those of the plain tube. The Nusselt number and the friction factor for employing the perforated strip inserts were found to be increased up to 2.65 and 1.75 times, respectively, over the corresponding plain tube. The heat transfer performance was evaluated and found to be 2.5 times higher compared to the plain tube based on the constant blower power. Finally, a correlation was developed with the experimental data for prediction of heat transfer in turbulent flow through a tube with perforated rectangular strip inserts.

Heat Transfer and Pressure Drop Characteristics in Turbulent Flow Through a Tube

An experimental investigation has been carried out for turbulent flow through a tube with perforated strip inserts. Strips were of mild steels with circular holes of different diameters. Flow varies, with ranging Reynolds numbers from 15,000 to 47,000. Air velocity, tube wall temperatures, and pressure drops were measured for a plain and strip-inserted tube. The heat transfer coefficient and friction factor were found to be 2.80 times and 1.8 times, respectively, that of the plain tube. The heat transfer performance was evaluated and found to be 2.3 times that of the plain tube based on constant blower power.

Biogas from mesophilic digestion of cow dung using charcoal and gelatin as additives

Biogas, a source of renewable energy is produced from bacteria in the process of biodegradation of organic matter under anaerobic conditions. A research work was performed to find out the production of biogas from cow dung using charcoal and gelatin as additives. Five laboatory scale experimental set-up were constructed using 0, 0.2, 0.4, 0.6 and 0.8% gelatin with cow dung as additive to perform the research work. For all the set-up 0.5% charcoal was also added. All the set-ups were made from 1-liter capacity conical flask. The amount of water and cow dung was used respectively 382 gm. and 318 gm. in every set-up. Total solid content was maintained 8% throughout all set-ups. The digesters were operated at ambient temperature of 26°-32°C. The total gas yield without using gelatin additive was found to be 12 L/kg cow dung. The maximum gas yield was found from 0.2% gelatin additive and 23% more as compared to without gelatin gas production. The retention time varied from 28 to 79 days for the experiments.

Biogas from mesophilic anaerobic digestion of cow dung using gelatin as additive

A research work was conducted to investigate the enhanced production ability of biogas from mesophilic anaerobic digestions of cow dung (CD) using gelatin as additive. Five laboratory scale digesters were constructed to digest cow dung, where one set up was used for digestion of cow dung without additive and the other set up were used for digestion with additive. Gelatin additive was added in the slurry of amount 0.29, 0,57, 0.85 and 1.14% (wt.). The digesters were made of glass conical flask of 1-liter capacity each. Cow dung was used 335 gm and water was used 365 gm in each experiment. In the slurry, total solid content was maintained 8% (wt.) for all the observations. The digesters were fed on batch basis. The digesters were operated at ambient temperatures of 26 – 35°C. The total gas yield was obtained about 14.4 L/kg CD for digestion without additive and about 65% more biogas for digestion with 0.29% gelatin additive. The retention time for digestion without additive was 38 days and with additive ret...