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The purpose of this paper is to show possible approaches which can be used for modeling complex flow phenomena caused by swirl burners combined with simulating coal combustion process using air- and oxy-combustion technologies. Additionally, the response of exist boiler working parameter on changing the oxidizer composition from air to a mixture of the oxygen and recirculated flue gases is investigated. Moreover, the heat transfer in the superheaters section of the boiler was taken into account by modeling of the heat exchange process between continuum phase and three stages of the steam superheaters.

An accurate solution of the flow field is required in order to predict combustion phenomena correctly for numerical simulations of the industrial pulverized coal (PC) boilers. Nevertheless, it is a very demanding task due to the complicated swirl burner construction and complex character of the flow. The presented simulations were performed using the discrete phase model for tracking particles and combustion phenomena in a dispersed phase, whereas the Eulerian approach was applied for the volatile combustion process modeling in a gaseous phase.

Applying the air- to oxy-combustion technology the temperature in the combustion chamber, decreased for investigated oxidizer compositions. This was caused by the higher heat capacity of flue gases which also influences on the level of the heat flux at the boiler walls. Simulations shows that increasing the O₂ concentration to 30 percent of volume base in the oxidizer mixture provided the similar combustion conditions as those for the conventional air firing. Moreover, the evaluated results give a good overview of differences between approaches used for complex swirl burners simulations.

Nowadays, the numerical techniques such as computational fluid dynamic (CFD) can be seen as an useful engineering tool for design and processes optimization purposes. The application of the CFD gives a possibility to predict the combustion phenomena in a large industrial PC boiler and investigate the impact of changing the combustion technology from a conventional air firing to oxy-fuel combustion.

This paper gives good overview on existing technique, approaches used for modeling PC boiler equipped with complex swirl burners. Additionally, the novelty of this work is application of the heat exchanger model for predicting heat loses in convective section of the boiler. This usually is not taken into account during simulations. The reader can also find basic concept of oxy-combustion technology, and their impact on boiler working conditions.

The purpose of this paper is to recommend a validated numerical model for simulation the flue gases heat recovery recuperators. Due to fulfill of this demand, the influences of ash fouling characteristics during the transient/steady-state simulation and optimization of a 3D complex heat exchanger equipped with inner plain fins and side plate fins are studied.

For the particle dispersion modeling, the discrete phase model is applied and the flow field has been solved using SIMPLE algorithm.

According to obtained results, for the recuperator equipped with combine inner plain and side plate fins, determination of ash fouling characteristics is really important, effective and determinative. It is clear that by underestimating the ash fouling characteristics, the achieved results are wrong and different with reality.

Finally, the configuration with inner plain fins with characteristics of: d_i =5 mm, d_o = 6 mm, d_g = 2 mm, d_k = 3 mm and NIPFT = 9 and side plate fins with characteristics of: T_F = 3 mm, P_F = 19 mm, NSPF = 17·2 = 34, W_F = 10 mm, H_F = 25 mm, L_F = 24 mm and ß = 0° is introduced as the optimum model with the best performance among all studied configurations.

Super 304HCu super austenitic stainless steel tubes containing 2.3 to 3 (Wt.%) of copper (Cu) is used in superheaters and reheater tubings of nuclear power plants. In general, austenitic stainless steels welded by conventional constant current gas tungsten arc welding (CC-GTAW) produce coarse columnar grains, alloy segregation and may result in inferior mechanical properties. Pulsed current gas tungsten arc welding (PC-GTAW) can control the solidification structure by altering the prevailing thermal gradients in the weld pool.

Super 304HCu tubes of Ø 57.1 mm and the wall thickness of 3.5 mm were autogenously welded using CC and PC-GTAW processes. Joints are characterized using optical microscopy, electron microscopy, energy dispersive spectroscopy and electron backscatter diffraction (EBSD) techniques. Hot tensile properties of the weld joints were evaluated and correlated with their microstructural features.

Current pulsing in GTAW has resulted in minimal eutectic film segregation, lower volume % of delta ferrite and appreciable improvement in tensile properties than CC-GTAW joints.

The EBSD boundary map and inverse pole orientation map of Super 304HCu weld joints evidence the grain refinement and much frequent high angle grain boundaries achieved using weld current pulsing.

Claimed to be programmable logic controllers (PLCs) that act like distributed control systems (DCSs), various people define hybrid systems differently: by functions, by industries served, by architecture, and even by no label at all. As a result, there is still confusion about the label “Hybrid Systems.” This paper aims to explore these issues briefly and to help understand and reduce confusion about these relatively recent hybrid systems, which are now also being called “Programmable Automation Controls” (PAC).

The paper compares DCSs, PLCs, centralized computer systems, use of industrial professional (personal) computers, original hybrid control systems, current hybrid control systems, evolution to PAC and shows evolution of new programming standards.

Hybrid control systems can readily become part of the overall plant productivity. This is a stepping‐stone towards complete enterprise control systems.

No small part of this capability is the emerging standard for easy consistent configuration of hybrid systems, regardless of the vendor who supplies them.

Because of the emerging configuration standard, the hybrid system can be re‐configured as needed due to plant changes or market swing. This provides the user with “agile manufacturing.”

More than a “cheap DCS,” these hybrid control systems can be an inexpensive stepping‐stone towards managing the business as it was meant to be managed. What is important is that these elements can be introduced in manageable increments to meet tight budgets.

Presents a review on implementing finite element methods on supercomputers, workstations and PCs and gives main trends in hardware and software developments. An appendix included at the end of the paper presents a bibliography on the subjects retrospectively to 1985 and approximately 1,100 references are listed.

The world of education within the UK is in turmoil. As in other countries there is a blurring between education and training. Teachers at all levels are faced with implementing the National Curriculum. Polytechnics are coming to terms with their independence from local authorities and dependence for (decreasing levels of) funding on the Polytechnics and Colleges funding Council. The Universities are grappling with their own new funding body — the Universities Funding Council. Students are likely to be faced with taking out ‘top‐up’ loans. The National Vocational Council lurks around the next comer to put in its ‘threepennyworth’.

Presents, at some length, the story of the writer’s father, sharing the history and experiences of a generation who prospered in the Chinese laundry industry. Chronicles the introduction of the wholesale shirt laundry, presenting new innovations and ideas and branching out into new regulated businesses in other fields, showing how emerging problems were tackled and overcome. Cites that most of the information is from memory, observation, letters and manuals. Considers the development and changes in the industry from 1930 to 1970, looking also at the accompanying changes in standards of living.

The complexity of controlling a diverse site is demonstrated by York Controls Group at Essex Police headquarters in Chelmsford. Varied building types with HVAC plant ranging from 20‐year‐old boiler‐fed radiators to modern air conditioning systems are managed by a York ISN building control system. Following the success of this application a number of remote police stations have been integrated within the main control system. Control integration is a hot topic in the controls industry with many manufacturers developing software gateways to allow their controllers to communicate with a range of buildings services plant as well as other manufacturers’ controllers. However, in the long term it is expected that common communications protocols will dispense with these gateways and representatives from all the European countries are currently working together to achieve agreed protocol.

Simulation and analysis of a real main steam line break transient at the Thermal Power Plant Drmno are presented. The main events of the transient were the closure of isolation valves in front of a high pressure turbine, an opening of a by‐pass line, and subsequent pipe break in front of isolation valves. Intensive pressure waves were generated and they propagated through the pipe network of the steam line, causing high fluid dynamic forces on the structure. The transient has been simulated by the computer code TEA‐01, based on the Method Of Characteristics with three characteristic directions. Several main steam line boundary conditions have been modelled and verified. Numerical results are compared with plant data logger records. Simulation has been performed for various scenarios in order to investigate the plant behaviour sensitivity on the boundary conditions. The phenomenology of the pressure waves propagation and the influence of the boundary conditions on these processes are described in detail, as well as fluid dynamic forces during the closure of isolation valves and subsequent pipe break in a section of the steam line in the vicinity of the pipe break.