Miroslav Raudensky

Optimal cooling of rolls in hot rolling

Abstract A laboratory experimental device was developed to allow full-scale measurements on roll cooling to be carried out. The full-scale tests use a complete configuration of rows of nozzles as in the plant conditions or prepared by a designer. The laboratory approach allows the design to be optimised or to compare old and new solutions. The tests provide a distribution of cooling intensity (heat transfer coefficient and heat flux) at the roll surface. The second step of the optimisation process is the usage of a numerical model for computation of temperature and roll crown in a hot rolling regime. A industrial typical rolling schedule is used to check the efficiency of cooling. A typical application of the experimental–numerical procedure is in improvements of cooling, in intensification of rolling and in design work. The paper shows how this approach can help in “making a decision” related to a prior plant application. Examples of the results and general recommendations for cooling are included.

Experimental Technique for Heat Transfer Measurements on Fast Moving Sprayed Surfaces

An experimental technique for the measurements of heat transfer distribution at spray cooled surfaces is described. The measurements were done at moving surfaces up to a velocity of 12 m/s. The samples of different cross sections (flat, profile, rail, etc.) can move linearly. Different approaches are used for the measurements of heat transfer coefficient (HTC) distribution or heat flux distribution at rotating cylindrical body. An inverse task for the computation of surface temperature, HTC, and heat flux distribution obtained from the measurements conducted for internal transient temperature is described. The paper describes necessary demands on experiment configuration and temperature measurements when studying highly transient processes (fast moving objects under spraying nozzles or high circumferential velocities of rotating surface). The results of HTC distribution for spray cooling are shown and are compared to water impingement density. Influence of water impingement density, water pressure, spray configuration, and surface velocity is studied. Examples for water nozzles and for mist nozzles (water-air) are given. Emulsions and oils are beneficial for some industrial applications of spray cooling. The cooling experiments performed with these liquids provide information about decrease of cooling intensity even for a low concentration of the oils in water. The results comparing the cooling properties of these liquids and their comparison to water are presented.

Performance Evaluations of Technology Transfer Offices of Major US Research Universities

By analyzing the highlights of the major activities reported by the technology transfer offices (TTOs) of twenty US major universities, the performances of TTO activities are quantitatively assessed and the associated scores are compared with each other. The key performance indicators, which govern the success of the university technology transfer, are specifically selected and examined. Two normalized metrics, overall performance metric (OPM) and patenting control ratio (PCR), which are the representing combined indicators for the TTO performance, are developed and demonstrated. The two metrics are evaluated for each university selected and compared to specifically provide a comprehensive overview of how good is the TTO of a university as compare to those of its peers. Finally, the factors for a successful TTO are described and the major unsolved issues are also discussed.

Liquid Sprays for Heat Transfer Enhancements: A Review

Sprays used for enhanced heat transfer are reviewed, starting from the spray characteristics, measurement methods, and spray dynamics, to spray heat transfer. Some results for spray heat transfer at large Reynolds numbers and surface boiling are also presented, including some recent results summarizing the effects of various injection parameters. It is recommended that basic principles of heat transfer be used to integrate various effects, such as coolant and surface temperatures, water and air flow rates, and injection conditions, into a concise form so that the results can be generalized and be applied to a large range of conditions.

In‐Line Heat Treatment and Hot Rolling

In‐line heat treatment of rolled materials is becoming increasingly used at hot rolling plants. The advantage of this method is the achievement of required material structure without the necessity of reheating.This paper describes a design procedure for cooling sections for the purpose of obtaining the required structure and mechanical properties. The procedure is typically used for the cooling of tubes, rails, long products and plates.Microstructure and nature of grains, grain size and composition determine the overall mechanical behaviour of steel. Heat treatment provides an efficient way to manipulate the properties of steel by controlling the cooling rate. The rate of cooling is defined by a heat transfer coefficient (HTC). Good controllability of HTC can be reached using either air‐water or water nozzles. Thus, an on‐line heat treatment with the assistance of spray nozzles enables a manufacturing process that can improve product performance by increasing steel strength, hardness and other desirable c...

Performances of Technology Transfer Activities of US Universities after Bayh-Dole Act

 Abstract—The activities and performance of university patenting and licensing are studied to gauge the effectiveness of the Bayh-Dole Act, which is the most influential pieces of US legislation on university technology transfer. Based on the raw data from five different sources, the annual numbers of the patents granted, the licenses signed, and the startup companies launched are analyzed. The correlation evaluations are performed for all data presented to quantify the trends at different time periods. It is found that the patenting and licensing activities in US universities slow down greatly after 2000 and remain actually flat until 2010, while the associate activities from 2010 to 2012 are active and strong again to the level in the period before 2000 and after the enactment of the Act. Some explanations on the differences found in the different data sources and different time periods are provided.

Assessments of technology transfer activities of US universities and associated impact of Bayh---Dole Act

Patents and licenses are foundational to successful technology transfer in universities. In this article, the activities and performance of university patenting and licensing are studied to gauge the effectiveness of the Bayh–Dole Act (the “Act”), the most influential piece of US legislation on university technology transfer (UTT). Based on raw data from five sources, the annual numbers of patents granted, licenses signed, startup companies launched, and research expenditures are analyzed. Correlations are performed for all data presented to quantify trends over different time periods. We found that patenting and licensing activities in US universities slowed down greatly after 2000 and remained flat until the period from 2010 to 2012, when activities recover to the level of strength characterizing the period before 2000 and after the enactment of the Act. We identify that economic recessions is the major cause to the flatness of the patenting activities during 2000s. We also explain some of the differences found among different data sources and time periods.

Fouling of Polymeric Hollow Fiber Heat Exchanger by Wastewater

Warm wastewater can be used as a source of heat for heat pumps in buildings such as gyms, swimming pools, and laundries. Unfortunately, heat exchangers installed in a sewage channel are negatively affected by fouling because deposits on the heat exchange surface create additional resistance to heat transfer and decrease the efficiency of the system. Heat exchangers consisting of polypropylene hollow fibers were prepared and tested to transfer heat from two types of wastewater: from a shower and from laundry. It was found that these devices have high thermal performance (with an overall heat transfer coefficient of up to 2,020 W/m(2) K) while working in clean conditions. Fouling tests showed that fouling strongly depends on the type of wastewater. During the experiment with shower wastewater the observed fouling was low because it was associated with the accumulation of a small amount of solid particles (particulate fouling). No significant decrease of overall heat transfer coefficient was observed during the two-week test in this case. The experiment with laundry wastewater showed that fouling was more extensive because it was associated with both types of fouling: particulate fouling and biofouling. The overall heat transfer coefficient was decreased by two times (from 1747 W/m(2) K to 863 W/m(2) K) during the 35-day experiment.

Development of accelerated cooling for new plate mill

Abstract The aim of the paper is to design the new wide plate mill. The work on the new cooling technology was supported by extensive laboratory testing while a simulator with full scale testing of cooling units was used. The principal objective of the investigation was to establish the design specification of equipment for accelerated cooling, particularly with respect to the product dimensions and steel grades. The possibilities of accelerated cooling are limited by technical parameters of cooling equipment such as thickness of water layer, flowrate, spray height, position of cooled surface to the nozzles and water or plate speed. These parameters were studied for different product temperatures and water impingement densities from 50 to 110 l s−1 m−2. The heat transfer coefficient was determined and compared for each case. There were three recognised significant cooling regions: water layer region, impinging jet region without water layer and impinging region with water layer, which must be taken into account. The application of the new cooling technology showed better flatness product and productivity higher than previous accelerated cooling system, even shorter cooling length. The rejection ratio by flatness problem of new mill was nearly half of the previous one.

Spray cooling by Al 2 O 3 and TiO 2 nanoparticles in water

An experimental investigation of spray cooling performed with water based nanofluids containing Al2O3 or TiO2 was conducted. The concentration of nanoparticles in the liquid was used in the experimental program was from 1 to 40 wt.%. A steel sensor with a soldered thermocouple was cooled from 200 °C. The liquid was sprayed on the surface with a full cone nozzle from distances of 40, 100 and 160 mm. The heat transfer coefficient was calculated at an interval of surface temperature from 100 °C to 50 °C by inverse modelling, and compared with the heat transfer coefficient of water cooling. The results surprisingly show a decrease of heat transfer coefficient on the cooled surface with a concentration of the nanoparticles.