IMECE2002-32095 CFD ANALYSIS OF LIQUID-COOLED EXHAUST MANIFOLDS IN A REAL ENGINE CYCLE

ABSTRACT Liquid-cooled exhaust manifolds are used in turbocharged diesel and gas engines in the marine and various industrial applications in order to minimize heat rejection to surrounding areas, maximize energy to the turbocharger, and maintain a maximum allowable skin temperature. A commercial CFD software FLUENT ® was used to analyze liquid-cooled exhaust manifolds in a real time engine cycle. Detailed information of flow property distributions and heat transfer were obtained in order to provide a fundamental understanding of the manifold operation. Experimental data was compared with the CFD results to validate the numerical simulation. Computations were performed to investigate the parametric effects of operating conditions on the performance of the manifold. Two different geometries were compared. One of them was found to have better performance, resulting in an approximately 2 to 3% fuel consumption improvement. INTRODUCTION Liquid-cooled exhaust manifolds are used on turbocharged diesel engines for marine, oilrig, and other industrial applications. The purpose of cooling the manifold is to prevent possible fire hazards by maintaining a maximum safe temperature on the exposed surfaces or "skin" of the manifold. The adverse effec

SIMULATION OF PULVERIZED COAL INJECTION IN A BLAST FURNACE

ABSTRACT A three-dimensional multiphase CFD model using an Eulerian approach is developed to simulate the process of pulverized coal injection into a blast furnace. The model provides the detailed fields of fluid flow velocity, temperatures, and compositions, as well as coal mass distributions during the devolatilization and combustion of the coal. This paper focuses on coal devolatilization and combustion in the space before entering the raceway of the blast furnace. Parametric studies have been conducted to investigate the effect of coal properties and injection operations

PREDICTION OF RACEWAYS IN A BLAST FURNACE

ABSTRACT In a blast furnace, preheated air and fuel (gas, oil or pulverized coal) are often injected into the lower part of the furnace through tuyeres, forming a raceway in which the injected fuel and some of the coke descending from the top of the furnace are combusted and gasified. The shape and size of the raceway greatly affect the combustion of the coke and the injected fuel in the blast furnace. In this paper, a three-dimensional (3-D) computational fluid dynamics (CFD) model is developed to investigate the raceway evolution. The furnace geometry and operating conditions are based on the Mittal Steel IH7 blast furnace. The effects of Tuyere velocity, coke particle size and burden properties are computed. It is found that the raceway depth increases with an increase in the tuyere velocity and a decrease in the coke particle size in the active coke zone. The CFD results are validated using experimental correlations and actual observations. The computational results provide useful insight into the raceway formation and the factors that influence its size and shape

2.45GHz radiofrequency fields alter gene expression in cultured human cells

AbstractThe biological effect of radiofrequency (RF) fields remains controversial. We address this issue by examining whether RF fields can cause changes in gene expression. We used the pulsed RF fields at a frequency of 2.45GHz that is commonly used in telecommunication to expose cultured human HL-60 cells. We used the serial analysis of gene expression (SAGE) method to measure the RF effect on gene expression at the genome level. We observed that 221 genes altered their expression after a 2-h exposure. The number of affected genes increased to 759 after a 6-h exposure. Functional classification of the affected genes reveals that apoptosis-related genes were among the upregulated ones and the cell cycle genes among the downregulated ones. We observed no significant increase in the expression of heat shock genes. These results indicate that the RF fields at 2.45GHz can alter gene expression in cultured human cells through non-thermal mechanism

Shaping the Future of Manufacturing with Simulation and Visualization

Computer simulation and virtual reality visualization have evolved to become critical emerging technologies in creating immersive virtual environments for numerous fields. The ability to allow people to go inside these virtual environments provides a unique, and effective tool for understanding complex manufacturing processes, and thus to innovate and to make significant improvements in a time and cost efficient way. It empowers people to work collaboratively and intuitively, prototyping and improving manufacturing processes virtually, and enabling smart manufacturing and improved decision-making for automation. As industry forges its way into the future, advanced computer simulation and visualization technologies will play an ever-increasing role in addressing the issues of productivity, energy, environment and quality, as well as workforce training to meet the challenges of tomorrow. The use of these technologies has already begun, and examples will be presented. Questions that will be addressed: How are simulation and visualization currently being used in industrial manufacturing? What are the challenges of integrating these technologies in industry? What does the future hold for manufacturing

NOx Reduction by NOx Recycle Approach

NOx recycle is a new approach for NOx reduction. It uses regenerable sorbent to adsorb NOx in the flue gas from a combustor followed by desorption, producing a highly concentrated NOx-laden stream containing both NO and N02. This stream is then sent back to the same combustor or to a separate combustor, where the NOx is reduced in the flame. Experimental studies have been performed to prove the concept of the NOx recycle approach. Results show that about 40% to 90% of NOx reduction efficiency can be achieved depending on experimental conditions. The NOx destruction efficiency in the combustor is affected by the recycle location, the amount of exit air and the composition of recycle gases. The most favorable recycle location is at the primary air duct. When NOx is recycled into the secondary air duct, the lower the exit 02, the better for the NOx destruction in the flame. Higher NOx reduction efficiency is obtained for the N02 recycle in comparison with the NO recycle. The concept of the NOx recycle approach has been employed in the NOXSO process, which is a dry, post-combustion flue gas treatment technology for coal-fIred boilers. The NOx recycle approach is expected to be a new alternative for NOx removal from flue gas, especially for integrated systems which use regenerable sorbent to simultaneously remove NOx, S02, and other pollutants emitted from combustion

NUMERICAL INVESTIGATION ON COOLING STRATAGIES IN A COMMERCIAL BLAST FURNACE HEARTH

ABSTRACT A blast furnace is the predominant iron-producing process in the U.S. It is widely believed that the blast furnace hearth refractory is the most dominant factor affecting the campaign life of a blast furnace. The hearth, where the liquid metal is collected, is made of carbon bricks. Cooling water is normally applied to the outside wall of the hearth. Wear of the carbon refractory occurs primarily because of erosion, which is related to the operating conditions of the hearth, such as the liquid flow in the hearth and the heat duty to the walls. Evaluation of fluid flow, heat transfer, and erosion patterns in the hearth are critical to the extension of the campaign life of a blast furnace, leading to the increase of productivity and saving of costs significantly. Advanced computational fluid dynamics (CFD) modeling techniques make it possible for providing detailed information on furnace conditions and parametric effects on performance. In this research, the blast furnace No. 13 at U.S Steel has been simulated using a comprehensive CFD model. The model was validated using the temperatures measured by thermocouples in the wall refractories of the furnace. The effects of cooling water on the temperature distributions as well as erosion patterns were evaluated. The results provide useful information for the furnace operations

Numerical Investigation of Cooling Strategy for Reducing Blast Furnace Hearth Erosions

ABSTRACT Hearth wearing is the key limit of a blast furnace campaign life. Hot metal flow pattern and temperature distributions are the two key variables to determine the rate and style of the hearth wearing. There are several strategies to control and reduce the hearth erosion, such as changing cooling water temperature and changing the heat transfer coefficient. In this paper, both cooling strategies are investigated using a comprehensive computational fluid dynamics (CFD) code, which was developed specifically for the simulation of blast furnace hearth. That program can predict the liquid flow patterns and temperature distributions of the hot metal as well as temperature profiles in the hearth refractory materials under different conditions. The results predicted by the CFD code were compared with actual industrial operation data. The cooling strategies are evaluated based on the energy analysis and effect on the hearth erosion