Soot surface growth in laminar hydrocarbon/air diffusion flames at atmospheric pressure

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76443/1/AIAA-2001-1077-966.pd

Soot Surface Growth and Oxidation in Diffusion Flames at Subatmospheric and Atmospheric Pressures

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76349/1/AIAA-2003-665-817.pd

Effects of Flow Properties on Soot Formation and Oxidation Rates in Flame Environments

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76893/1/AIAA-2004-641-494.pd

Soot Surface Reactions in High-Temperature Laminar Diffusion Flames

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76360/1/AIAA-3230-367.pd

Soot Formation and Oxidation in Laminar Flames

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76320/1/AIAA-2006-1508-194.pd

Insulation Performance of Building Components and Effect on the Cooling Load of Homes in Saudi Arabia

A common practice in the construction of residential and commercial buildings in Saudi Arabia is to insulate the outer walls and windows only. Other building components such as the roof, columns and slabs, and doors are usually neglected. Moreover, vital components such as the roof and windows are especially neglected in commercially built residential and commercial buildings. The aim of this study is to put this common impression and practice to the test by quantifying the contribution of every building component to the overall air-conditioning load of the building. The hypothesis evaluated in this paper is that despite the common practices, there could be an optimum selection of insulators for the building components that yields the lowest energy consumption and maximum savings not only in energy costs but also installation costs. The required air-conditioning load is determined using manual calculations and the HAP software package for 1022 possible configurations. The findings of the analysis point to the importance of the roof, as it is the major contributor to the thermal load, followed closely by columns and slabs, with 44.2% of the overall cooling load. It is found that a single wall consisting of 2 cm of cement plaster, 20 cm of cement–polyurethane brick, and 2 cm of cement plaster is less expensive and has higher thermal resistance than any of the more expensive double walls. The study found one scenario of possible configurations with the optimized selection of building materials and their insulation materials that provides the most effective insulation at the lowest cost

Enhancing Solar Still Performance Using Vacuum Pump and Geothermal Energy

Improvement in the performance of a solar still is investigated with the integration of a geothermal cooling system and a vacuum pump. Geothermal cooling is simulated to provide a cold, effective underground water temperature, which could reach 15⁻25 °C below ambient. Cooling is achieved by circulating water underground. As a result of this circulation, the cold fluid from the ground flows into a counter flow shell and tube heat exchanger. A vacuum pump is used to keep the solar still at a certain vacuum pressure. The sizes of the geothermal system and solar still are designed in such a way that the water outlet temperature from the ground and its flow rate are capable of condensing the entire vapor produced by the still. An analytical model was developed and then solved using the Newton⁻Raphson method for solving non-linear equations. A prototype was built to validate the analytical model. The results were in close agreement. A 305% increase in daily water productivity resulted from the proposed enhancements. After experimental validation, the effects of various parameters such as vacuum pressure, ambient temperature, and wind speed on the yield of geothermal solar still were examined. It was found that the increase in vacuum pressure enhanced performance, whereas the increase in wind speed had a detrimental effect on the yield of the solar still. A higher ambient temperature increased the yield of the solar still. Finally, the design of the heat exchanger for condensing the distilled water using geothermal cooling water was also investigated in terms of the increase in UA (the product of overall heat transfer coefficient and the area of heat exchanger) with inlet cooling geothermal water temperature

Performance Assessment of an Ice-Production Hybrid Solar CPV/T System Combining Both Adsorption and Vapor-Compression Refrigeration Systems

The technology of a hybrid solar concentration photovoltaic/thermal (CPV/T) system is an efficient way of converting solar energy to heat and electrical power, in which overall energy-extraction efficiency is at its highest. In this study, numerical dynamic simulation models were developed for a hybrid solar CPV/T system and an adsorption refrigeration system (ARS). Under the climatic conditions of Riyadh all year round, the electrical and thermal powers generated by the CPV/T system were used to estimate the ice production of both the vapor compression refrigeration system (VCS) and the ARS. The CPV/T system can provide a thermal energy of 37.6 kWh and electrical energy of 24.7 kWh a day on average over the year using a 12.5 m2 facing area of Fresnel lenses. The ARS employed an advanced approach which used Maxsorb III adsorbent packed in two aluminum foam beds. An optimum cycle time of the ARS was adapted for each month to match the variation in the thermal energy, while a variable-speed compressor was chosen for the VCS. Due to its higher coefficient of performance (COP), the proposed solar hybrid system can produce 494.4 kg of ice per day while sharing 84.5% of the VCS. The average solar COP over the year of the hybrid system can attain 0.875, which represents a promising value for a solar ice-production system

Examination of Using Aluminum-Foam/Finned-Tube Beds Packed with Maxsorb III for Adsorption Ice Production System

Producing ice using adsorption systems can represent a sustainable solution and meet the recent global environmental regulations as they use natural refrigerants and can be driven by solar energy. However, the beds used in these systems still have low thermal and adsorption characteristics. This study investigates numerically the use of an emerging aluminum foamed bed packed with advanced Maxsorb adsorbent in a two-bed adsorption system and reports cases of performance improvements compared to the classical finned-tube based system used to produce ice. A comprehensive 2-D transient pressure distribution model for the two beds was developed and validated. The model considers the temporal and spatial variations of the two beds’ parameters, while the effect of the thermal mass and heat transfer effectiveness of the condenser and evaporator components are imitated at the boundary conditions for bed openings using two zero-dimensional models. The results show the interrelated effects of varying the cycle times from 400 s to 1200 s with 2, 5, and 10 mm foam thicknesses/fin heights on the overall performance of both systems. The Al-foam based system demonstrated the performance superiority at a 2 mm foam thickness with maximum ice production of 49 kgice/kgads in 8 h, an increase of 26.6% over the counterpart finned-tube based system at a 400 s cycle time. The best COP of 0.366 was attained at a 5 mm foam thickness and 1200 s with an increase of 26.7%. The effective uptake of the Al-foam based system was reduced dramatically at a 10 mm foam thickness, which deteriorated the system performance

Examination of Using Aluminum-Foam/Finned-Tube Beds Packed with Maxsorb III for Adsorption Ice Production System

Producing ice using adsorption systems can represent a sustainable solution and meet the recent global environmental regulations as they use natural refrigerants and can be driven by solar energy. However, the beds used in these systems still have low thermal and adsorption characteristics. This study investigates numerically the use of an emerging aluminum foamed bed packed with advanced Maxsorb adsorbent in a two-bed adsorption system and reports cases of performance improvements compared to the classical finned-tube based system used to produce ice. A comprehensive 2-D transient pressure distribution model for the two beds was developed and validated. The model considers the temporal and spatial variations of the two beds’ parameters, while the effect of the thermal mass and heat transfer effectiveness of the condenser and evaporator components are imitated at the boundary conditions for bed openings using two zero-dimensional models. The results show the interrelated effects of varying the cycle times from 400 s to 1200 s with 2, 5, and 10 mm foam thicknesses/fin heights on the overall performance of both systems. The Al-foam based system demonstrated the performance superiority at a 2 mm foam thickness with maximum ice production of 49 kgice/kgads in 8 h, an increase of 26.6% over the counterpart finned-tube based system at a 400 s cycle time. The best COP of 0.366 was attained at a 5 mm foam thickness and 1200 s with an increase of 26.7%. The effective uptake of the Al-foam based system was reduced dramatically at a 10 mm foam thickness, which deteriorated the system performance