Browsing by Author "Luthan, Jurizal Julian"
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Item Computational two-phase flows in conduits with and without heat addition(Texas Tech University, 1992-05) Luthan, Jurizal JulianThe main objectives of this study of two-phase ga^-liquid flows are to reduce the time and cost and to improve prediction capability of process development in comparison with purely empirical design methods. The problem associated with mathematical modeling of the detailed flow patterns in two-phase flows involves the solution of strongly coupled, nonlinear partial differential equations of the field equations. The solution of these equations lies well beyond any existing analytical approach. Therefore finite-diflference approximations, based on IPSA (Inter-P,hase £lip A^ialyzer) algorithm, are used to solve the problem. Three cases are considered in this study. The first is the problem of two-phase gas-liquid stratified flow with constant properties for both fluids. The second is the problem of idealized boiling problem where, again, the properties of the two fluids are taken to be constant. As the last one, the previous problem is revisited by relaxing the simplifying assumptions. The last two cases are treated as pseudo-transient problems. In addition, all three problems are computed with one spatial dimension dependency. While the flow model employed is two-fluid or six-equation model. The results are then compared with the available analytical solution and experimental data. It was found that they are satisfactorily comparable. The methodology developed may be useful in future research with other fluid pairs or components.Item Performance analysis of absorption heat transformer(Texas Tech University, 1987-05) Luthan, Jurizal JulianMany industrial sectors reject heat to the atmosphere in the form of hot water with temperatures between 40° and 70°C. This rejected heat, owing to its low temperature, is of little significant to the generating processes unless a means to boost its temperature is available. However, there is a device with which this low grade heat can be upgraded; that is. by employing a vapor absorption heat transformer (AHT). It is anticipated that by using this device the amount of heat rejected to the atmosphere can be reduced by recycling the upgraded low heat back to the process. This research will investigate the performance of Ammonia-Water and Lithium Bromide aqueous solutions in a single stage AHT. Comparison will be made between the findings of the two proposed aqueous solutions for the same system and operating parameters to determine the relative merit of each one.