Mathematical modeling of cold cap
The ultimate goal of studies of cold cap behavior in glass melters is to increase the rate of glass processing in an energy-efficient manner. Regrettably, mathematical models, which are ideal tools for assessing the responses of melters to process parameters, have not paid adequate attention to the cold cap. In this study, we consider a cold cap resting on a pool of molten glass from which it receives a steady heat flux while temperature, velocity, and extent of conversion are functions of the position along the vertical coordinate. A one-dimensional mathematical model simulates this process by solving the differential equations for mass and energy balances with appropriate boundary conditions and constitutive relationships for material properties. The sensitivity analyses on the effects of incoming heat fluxes to the cold cap through its lower and upper boundaries show that the cold cap thickness increases as the heat flux from above increases, and decreases as the total heat flux increases. We also discuss the effects of foam, originating from batch reactions and from redox reactions in molten glass, and argue that models must represent the foam layer to achieve a reliable prediction of the melting rate as a function of feed properties and melter conditions.
Glass Furnace Model (GFM) development and technology transfer program final report.
A Glass Furnace Model (GFM) was developed under a cost-shared RD (2) solve problems related to production and glass quality by defining optimal operating windows to reduce cullet generation due to rejects and maximize throughput; and (3) make changes in furnace design and/or operation to reduce critical emissions, such as NO{sub x} and particulates. A two-part program was pursued to develop and validate the furnace model. The focus of the Part I program was to develop a fully coupled furnace model which had the requisite basic capabilities for furnace simulation. The principal outcome from the Phase I program was a furnace simulation model, GFM 2.0, which was copyrighted. The basic capabilities of GFM 2.0 were: (1) built-in burner modelsmore » that can be included in the combustion space simulation; (2) a participating media spectral radiation model that maintains local and global energy balances throughout the furnace volume; and (3) a multiphase (liquid, solid) melt model that calculates (does not impose) the batch-melting rate and the batch length. The key objectives of the Part II program, which overlapped the Part I program were: (1) to incorporate a full multiphase flow analytical capability with reduced glass chemistry models in the glass melt model and thus be able to compute and track key solid, gas, and liquid species through the melt and the combustion space above; and (2) to incorporate glass quality indices into the simulation to facilitate optimization studies with regard to productivity, energy use and emissions. Midway through the Part II program, however, at the urging of the industrial consortium members, the decision was made to refocus limited resources on transfer of the existing GFM 2.0 software to the industry to speed up commercialization of the technology. This decision, in turn, necessitated a de-emphasis of the development of the planned final version of the GFM software that had full multiphase capability, GFM 3.0. As a result, version 3.0 was not completed; considerable progress, however, was made before the effort was terminated. The objectives of the Technology Transfer program were to transfer the Glass Furnace Model (GFM) to the glass industry and to promote its widespread use by providing the requisite technical support to allow effective use of the software. GFM Version 2.0 was offered at no cost on a trial, six-month basis to expedite its introduction to and use by the industry. The trial licenses were issued to generate a much more thorough user beta test of the software than the relatively small amount completed by the consortium members prior to the release of version 2.0.« less
Badush Dam, NW Iraq : A Geological Study
The river Tigris flows from Turkey towards Iraq in its northwestern part dissecting the whole Iraqi territory. During 1981– 1986 a very large earth fill dam was constructed, which is Mosul Dam impounding the flow of the Tigris River. It is the largest dam in Iraq and one of the largest in the Middle East. The geological conditions of the dam site and surroundings, however, are not suitable due to thick exposures of the Fatha Formation, which consists of marl, clay, limestone and gypsum. The gypsum and limestone beds are highly karstified causing severe problems to the dam foundation. Mosul dam suffers from serious problems due to the presence of karstified rocks; therefore, the Ministry of Irrigation in Baghdad, decided to construct a protection dam downstream of Mosul Dam; it is called Badush Dam. The geological conditions at Badush Dam site are the same as those at Mosul Dam site, which means the foundations of the dam are located on karstified rocks. Therefore, grouting works were planned and designed and it was partly performed from the beginning of the construction in 1988. The construction of the dam; however, stopped in 1991 due to the consequences of the First Gulf War. The constructed parts of the dam are (30 – 40) %. In this study, we have presented the main problems, which will cause real danger to Badush Dam, if its construction is re-started, and we have suggested many requirements to avoid any hazard that may cause the collapse of Badush Dam.