Tom Honeyands

Gas dispersion through porous nozzles into down-flowing liquids

Abstract In this study the flow characteristics of a down-flowing gas–liquid column incorporating a submerged entry porous nozzle system are considered. A model based on one-dimensional drift flux analysis and critical Weber number for stable bubble size is presented. The model is used to predict the bubble size and gas void fraction as a function of the gas and liquid flow velocities within the bubbly flow regime, and can also be used to predict the gas and liquid flow conditions at which a transition from bubbly to churn-turbulent flow occurs. Reasonable agreement was found between the model predictions and experimental measurements carried out in the column using an optical fibre probe. The implications of these results for operation of submerged entry nozzle systems in the continuous casting of steel are also discussed.

A Novel Measurement of Voidage in Coke and Ferrous Layers in Softening and Melting under Load Test Using Synchrotron X-ray and Neutron Computed Tomography

For the first time, the bed voidage of samples from interrupted softening and melting (S&M) under load tests was measured directly using computed tomography (CT). The large size, fused structure and high metallic iron content of the samples required the very high energy synchrotron X-ray source for scanning; samples produced at higher temperatures, e.g., 1 450°C, required neutron CT to allow adequate penetration of the samples. This method was able to uniquely and accurately identify the volumes, distributions, and structures of coke, ferrous, and void in the S&M samples, and quantify the tortuosity of the voids. This information is critical for analysis of the pressure drop–contraction relationship in the S&M under load test, and will allow the improvement of the treatment of the cohesive zone in numerical models of the blast furnace.

A review of high-temperature experimental techniques used to investigate the cohesive zone of the ironmaking blast furnace

ABSTRACT The softening and melting (S&M) under load test is widely used as a laboratory-scale routine test to investigate the behaviour of ferrous burden materials in the cohesive zone (CZ). However, it has been more than 30 years since the last comprehensive review and over that time, operational conditions in large, high-production blast furnaces (BFs) have changed substantially. This review provides a summary and critique of current laboratory methods and practices used to evaluate the behaviour of ferrous materials in the CZ, focussing on the various configurations and operating conditions employed for the S&M under load test. Moreover, the review proposes and argues for a more integrated approach to S&M analysis for research, one which promotes a more comprehensive understanding of ferrous burden behaviour in the CZ region and which, in turn, enables the development of more robust, routine tests for the purpose of material comparisons and prediction of BF performance.