Smoke Movement in High Rise Building - Coursework Example

Research methodology on smoke movement in high rise building Name Date Course Research methodology on smoke movement in high rise building Zone modeling The zone modeling theory is usually used to explain the smoke interface when dealing with fire and smoke in high rise building. According to the model, the room under fire is divided into two zones. The lower zone is composed of fresh air and it is regarded as the cold zone. It is also the area that supports combustion. The other layer is the hot upper layer and it is mainly composed of the smoke. This is because the movement of smoke is usually controlled by the gas equations which are also explained in the model. The movement of the smoke in the high rise building is due to the movement of the burnt gases away from the lower zone composed of fresh air. The semi-empirical equation for mass, momentum, energy and chemical species are useful in the analysis of the smoke movement in the zone modeling. This is considering that movement of the smoke is similar to the air movement. The zone modeling also explains why the smoke moves away from the fire to the other parts of the building. It is also for this reason that smoke is able to move to the other parts of the high rise building even after the fire has been confined in a particular room. The difference in temperature and pressure between the two zones is also responsible for the movement of the smoke in a high rise building (Reszka, 2007). Field models/CFD The field modeling concept is based on the flow of fluids. This is achieved through the analysis of the fluid flow using mathematical equations. The laws of nature that are also related to the fluid flow are also put in place during the analysis (Klote, 2002). The laws of conservation of energy as well as the mass conservation and momentum conservation laws are the natural laws that are usually considered. On the other hand, in the case of a high rise building, various models are also incorporated in the field model in order to explain some of the phenomenon. The combustion model is used to explain the behavior of fire in a high rise building and how it affects the movement of smoke. The principles of buoyancy are also important in determining the movement of smoke in the high rise building. It is for this reason that the field modeling concepts incorporates the turbulence model to explain the smoke movement. The soot model is also an important model that is used in the field model to explain the movement of smoke in the high rise building. The combination of the models is thus useful in terms of clearly analyzing the laws of nature in relation to the movement of smoke in a high rise building during a fire incident. During the computation process, a pre-processor and a post processor are usually used. A pre-processor is a term that is used to describe the problem. The computer is then used for the purposes of analyzing the data obtained and hence analyzing the smoke movement in a high rise building. Fire Dynamic simulator The fires dynamic simulator is a model of the computational fluid dynamics that is mainly concerned with the fluid flow in relation to fire. The movement of smoke is mainly driven by heat transport and distribution in a high rise building (McGrattan, 2003). This therefore requires the use of the large eddy simulations and the Navier stokes equation. The solution to these equations can thus be obtained through the use of the fire dynamics simulators. It also plays an important role in terms of determining the movement of smoke in a high rise building that is under fire. The fire dynamics simulator is software that was designed in the United States of America and it plays a major role in the analysis of the fire and smoke movement in a high rise building. The evolution of the fire is directly related to the production and movement of smoke. However through the use of the fire dynamic simulators, the fire evolution can be easily determined. The computation of numerical equations as well as data is also achieved through the use of the software. The relationship between the fire and the smoke in the high rise building can also be determined through the use of the software. It is thus easy to explain the movement of smoke as well as the fire dynamics through the use of the software. The use of the software has also played an important role in terms of designing the smoke handling system. Sub-models for turbulence Turbulence is characterized with temporal irregularity and randomness. It is for this reason that various sub-models are associated with turbulence. The conservation equations have to be solved for the purposes of dealing with the movement of smoke in high rise building. The model of direct numerical simulation is for the purposes of dealing with rapid fluctuations which is associated with turbulence. On the other hand, the large eddy simulation method is also a sub-model of turbulance. This model deals with smaller volumes. This is applicable to the movement of smoke particles in the high rise building during a fire. The sub-models of turbulence also deal with time density and mass which are associated with the movement of smoke. The Averaging methods in the analysis of the data related to turbulence are thus used in the process. The mass continuity equations area is also useful in the sub-models of turbulence. This is considering the complex nature of turbulence. Momentum conservation is also an important in terms of dealing with the movement of smoke. The use of the momentum equations together with the energy equations are also useful in terms of determining the heights that the smoke can rise within a high rise building during a fire. The chemical species equation also affects the movement of smoke as it deals with density in relation to the chemical composition of the smoke. The combination of the sub-models therefore plays an important role in determining the movement of smoke in a high rise building fire (Kandus, et al, 2010). Sub-models for combustion Combustion is mainly a transfer process of energy and mass. The exothermic reaction that is involved leads to the combustion of the combustible materials and hence the production of smoke. The combustion sub-models are useful in terms of explaining the time taken for the combustion process to take place and hence the smoke production. The eddy breakup model is one of the main sun-models of combustion. It mainly deals with the chemical reaction that takes place during combustion and hence the production of smoke. It also incorporates the principles of the soot models which can be used to explain the movement of soot during the process. The following equation is usually used during the model. 1 kg fuel + s kg of oxidant ® (1+s) kg of products s represents oxidant ratio to stoichiometric fuel. The products are water and carbon dioxide. Laminar flamelet combustion model is also a sub-model of combustion. The model explains the composition of the flame and how it leas to turbulence. This in turn determines the time and the effects that the flame can have during the combustion process. The effect of the flame can lead to the production of certain amount of smoke and hence its importance in determining the movement of smoke in a high rise building. The effects of temperature also affect the movement of smoke in a high rise building. These factors are clearly outlined in the sub-model as temperature is directly related to combustion (Hostikka, et al, 2011). FDS limitations The use of the FDS is due to its level of accuracy in some of the aspects. However it has some limitations which affect the outcome of the results in relation to the studies involving smoke movement in high rise building. Changes to the heat of combustion are not taken into account when using the FDS. This has a negative impact on the results regarding the movement of smoke because the temperature changes directly affect the smoke movement. FSD is also insensitive to the soot yield which is directly involved in the study of the smoke movement in high rise building (Gobeau, 2007). The amount of soot produced in the high rise building fire plays an important role in determining the spread of the smoke in the high rise building. The heat from the smoke layer is also an important issue that is not adequately addressed through the use of the FDS. This limitation directly affects the outcome of the studies regarding the movement of smoke in high rise building. This is because the heat produced has an impact on the expansion of gases and hence the spread of the smoke in the high rise building. The properties of materials are also not put into consideration and hence affecting the outcome of the results. On the other hand, the production of animation on the computer screen is important in terms of analyzing the smoke movement in high rise building fires. This is a limitation of the FDS as it does not have the ability to do so. The limitations in the numerical grid In the analysis of fire, the numerical grid is used to divide the enclosure into several cells for the purposes of obtaining accurate results. The temperatures and pressure are the main factors that affect the spread of the smoke from one area to the other in a high rise building. The accuracy of using the numerical grids is dependant on their sizes. This means that the smaller the grids the more accurate the results. However this also presents a limitation in the use of the numerical grid. It takes much time to make the analysis while using the high resolutions to obtain the results. The accuracy is thus low when using the numerical grid as larger cells are usually used in most instances. The use of the numerical grid also ignores some of the important parameters like temperature and the fire spread. These parameters have a direct impact on the spread and movement of smoke in a high rise building during a fire incident. It is thus evident that the main limitation of using the numerical grid mainly lies on its level of accuracy which is low. On the other hand, the use of the numerical grid is a tedious process that requires a lot of time. This has a negative impact on the accuracy of the results obtained from the process. Fire description, development and flow conditions The description of fire is mainly dependant on its cause. This is considering that most of the fires in the high rise building are caused by an electric fault. The cause of the fire also has a role in terms of determining the amount of smoke that will be produced and its chemical composition. However it is important to note that the development of the fire is usually initiated by rate of heat release. This plays an important role in determining how fast the fire will spread. On the other hand, the development of the fire in a high rise building also determines the rate at which the smoke will develop and spread to the other parts of the building. The flow conditions of the fire are however guided by several aspects. During the fire flow, several laws are applicable and are closely related to nature. The energy flow as well as momentum plays an important role in the flow of the fire. However, it is important to note that the flow of the smoke is faster that the flow of fire in a high rise building. This is because fire is dependant on various factors including the materials undergoing combustion as well as the prevailing weather conditions (Satula, 2002). FDS evaluation The evaluation of the FSD is for the purposes of determining the efficiency of the performance of the models. During the evaluation, is always important to ensure that the model used is determined and its concepts clearly outlined. This determines the accuracy of results in terms of determining the spread and the movement of smoke in high rise buildings. The theoretical concepts of the models used are also useful in terms of evaluating the FSD. The numerical concepts that are involved during the calculation it also important in terms of evaluation. This should be done for the purposes of ensuring that the method is accurate. The accuracy of the FDS is important in terms of determining the rate at which smoke spreads in the high rise building. This is because the accuracy of the results obtained through the use of the software gives accurate reflection with regards to the spread of the smoke in high rise building. Verification of fire dynamics simulator The accuracy of the data obtained is important in terms of determining the accuracy of the model. However, it is important to note that the equations used are important during the verification process. The accuracy of the model is however not dependant on the accuracy of the data. During the verification process the equations that were used in the model is usually used in the process. This is also considering that several equations may be used in the model depending on the parameters that are being determined. The equations used also determine the accuracy of the movement of the smoke in a high rise building in relation to the fire. Accurate results will be determined upon the verification process which has to be conducted using the guidelines provided in the FSD. Validation The validation process is an important aspect of determining the accuracy of the mathematical aspects of the experiments. The validation is also important in terms of ensuring that the experiment is within the acceptable limit. This means that validation ensures that reasonable results are obtained from the experiment. Comparisons are also important during the validation process. The comparisons should be based on the previous studies and experiments. However the comparison with the previous experiments should only be based on recent experiments. This is because of the changes that usually occur with time in relation to the mathematical concepts. Comparisons with the standards that have already been set may also be used as it determines the range under which the results falls. ISO is an international standards body and it can be used for the purposes of comparing the results. The validity of the experiment should be based on the limits that have been set by the standards body. This produces accurate results as the standards set by ISO is recognized internationally. Validation of fire dynamic simulator on smoke movement in high rise building In the validation of the fire dynamic simulator on smoke movement, the concepts of heat transfer has to be analyzed. This is because heat transfer is responsible for the changes in temperature at different parts of the building. On the other hand, it is also important to note that the concepts of zone modeling have to be considered. This is because of the difference in temperature at different parts of the building which is also responsible for determining the expansion of gases and hence the smoke movement. The use of the numerical grid is also important in terms of analyzing the temperatures and hence the smoke movement in the high rise building. Comparisons can also be made from previous studies regarding the smoke movement in high rise building. However, it is also important to ensure that the comparisons are made from credible experiments. An example is the experiments from the United States of America Nuclear Regulatory commission. This is institution has carried out several credible experiments in fire dynamics simulator on smoke on smoke from high rise building (McGrattan, 2007). The conditions of the rooms in terms of their temperatures should also be considered during the validation process. This is because the smoke can move from floors above with much lower temperatures as compared to the areas that have high temperatures and pressure. The equations that guide the flow of energy as well as the momentum should also be considered during the validation process so as to determine the accuracy of the results. The results after the validation should also be within the acceptable limits so as to ensure that the findings are reasonable, practical and accurate. References Reszka, P, 2007, The Dalmarnock Fire Tests: Experiments and Modeling, in: C. A. E. Guillermo Rein, R. Carvel (Eds.), The Dalmarnock Fire Tests: Experiments and Modeling, The University of Edinburgh, McGrattan, K, 2003, Fire Dynamics Simulator (Version 4) – Technical Reference Guide, NISTIR 6783. Klote, J, 2002, Principles of Smoke Management, American Society for Heating Refrigeration and Air Conditioning Engineers, Atlanta, GA. Gobeau, N, 2007, "Evaluation of CFD Methods for Predicting Smoke Movement in Enclosed Spaces," Fire Protection Engineering, Spring. McGrattan, K, 2007, Verification and Validation of Selected Fire Models for Nuclear Power Plant Applications, Volume 7: Fire Dynamics Simulator, U.S. Nuclear Regulatory Commission, Office of Nuclear Regulatory Research (RES), Rockville, MD, and Electric Power Research Institute (EPRI), Palo Alto, CA. NUREG-1824 and EPRI 1011999. Satula, J, 2002, "Applications of the Fire Dynamics Simulator in Fire Protection Engineering Consulting," Fire Protection Engineering, Spring, Kandus, G, et al, 2010, Performance of BPSK Subcarrier Intensity modulation free-space optical communications using a log-normal atmospheric turbulence model, Photonics and Optoelectronic (SOPO), 2010 Symposium on, pp. 1-4. Hostikka, S, et al, 2011, A mixture fraction combustion model for large scale fire simulation, Proceeding of ASME International Mechanical Engineering Congress and Expedition (IMECE'01), pp. 11-16. Read More

The principles of buoyancy are also important in determining the movement of smoke in the high rise building. It is for this reason that the field modeling concepts incorporates the turbulence model to explain the smoke movement. The soot model is also an important model that is used in the field model to explain the movement of smoke in the high rise building. The combination of the models is thus useful in terms of clearly analyzing the laws of nature in relation to the movement of smoke in a high rise building during a fire incident.

During the computation process, a pre-processor and a post processor are usually used. A pre-processor is a term that is used to describe the problem. The computer is then used for the purposes of analyzing the data obtained and hence analyzing the smoke movement in a high rise building. Fire Dynamic simulator The fires dynamic simulator is a model of the computational fluid dynamics that is mainly concerned with the fluid flow in relation to fire. The movement of smoke is mainly driven by heat transport and distribution in a high rise building (McGrattan, 2003).

This therefore requires the use of the large eddy simulations and the Navier stokes equation. The solution to these equations can thus be obtained through the use of the fire dynamics simulators. It also plays an important role in terms of determining the movement of smoke in a high rise building that is under fire. The fire dynamics simulator is software that was designed in the United States of America and it plays a major role in the analysis of the fire and smoke movement in a high rise building.

The evolution of the fire is directly related to the production and movement of smoke. However through the use of the fire dynamic simulators, the fire evolution can be easily determined. The computation of numerical equations as well as data is also achieved through the use of the software. The relationship between the fire and the smoke in the high rise building can also be determined through the use of the software. It is thus easy to explain the movement of smoke as well as the fire dynamics through the use of the software.

The use of the software has also played an important role in terms of designing the smoke handling system. Sub-models for turbulence Turbulence is characterized with temporal irregularity and randomness. It is for this reason that various sub-models are associated with turbulence. The conservation equations have to be solved for the purposes of dealing with the movement of smoke in high rise building. The model of direct numerical simulation is for the purposes of dealing with rapid fluctuations which is associated with turbulence.

On the other hand, the large eddy simulation method is also a sub-model of turbulance. This model deals with smaller volumes. This is applicable to the movement of smoke particles in the high rise building during a fire. The sub-models of turbulence also deal with time density and mass which are associated with the movement of smoke. The Averaging methods in the analysis of the data related to turbulence are thus used in the process. The mass continuity equations area is also useful in the sub-models of turbulence.

This is considering the complex nature of turbulence. Momentum conservation is also an important in terms of dealing with the movement of smoke. The use of the momentum equations together with the energy equations are also useful in terms of determining the heights that the smoke can rise within a high rise building during a fire. The chemical species equation also affects the movement of smoke as it deals with density in relation to the chemical composition of the smoke. The combination of the sub-models therefore plays an important role in determining the movement of smoke in a high rise building fire (Kandus, et al, 2010).

Sub-models for combustion Combustion is mainly a transfer process of energy and mass. The exothermic reaction that is involved leads to the combustion of the combustible materials and hence the production of smoke.

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