Study of Designing and Operating Parameters of Rotary Air Preheaters

, M.Sc. Thesis Sharif University of Technology Ahmadi Partovi, Ebrahim (Author) ; Saidi, Mohammad Hassan (Supervisor) ; Kazemzadeh, Siamak (Supervisor)

Abstract

In order to promote the efficiency of fossil fuel power stations, rotary air preheaters are used to warm the air entering the boiler. So, knowing the essential parameters of such exchangers and their effect on the efficiency is the primary objective and choosing the appropriate parameters and the dimensions reducing the liquid pressure, weight of exchangers and subsequently the maintenance expenses would be the secondary objective.
In this research we tried to know the principles of regenerative convertors introducing the tentative air preheaters and their functional characteristics .We also assessed the factors in designing the ideal tentative air preheaters including the type of...

Comparison of Transfer Functions in Dual Porosity-Dual Permeability Models in Simulation of 3D Black-Oil Naturally Fractured Reservoirs Using Structured Grids

, M.Sc. Thesis Sharif University of Technology Mohammadnejad, Hamed (Author) ; Taghizadeh Manzari, Mehrdad (Supervisor)

Abstract

In this work, simulation of 3D three-phase naturally fractured reservoirs is studied. Both Dual Porosity and Dual Porosity-Dual Permeability models which are commonly used in commercial softwares such as ECLIPSE and CMG, are utilized. The governing equations include the mass (in Black-oil model) and linear momentum (in Darcy law form) equations, which are converted into pressure equations and a set of transport equations for the saturations and mole fractions of phases. These equations are solved once for the matrix domain and subsequently for the fracture domain. These two set of equations are coupled through transfer functions. The accuracy of computations significantly depends on how...

Analysis of Delamination in Fiber-reinforced Composite Laminates Using Multiscale Modeling

, M.Sc. Thesis Sharif University of Technology Abdolmohammadi, Nafiseh (Author) ; Hosseini Kordkheili, Ali (Supervisor)

Abstract

This study presents delamination in fiber-reinforced composite laminates by using multiscale modeling. The meso modeling is used to derive the relationship between microcrack density and damage parameters. Next the selected failure model is applied to analyze the macroscale modeling. The progress of failure terms and the reduction of fiber and matrix properties implemented into ABAQUS/Standard, which enables an individual to create a new material behavior through the user subroutine UMAT. In the following, the contours associated with each of the damage parameters are obtained in each of the damage mode. Then for a specific material, the relationship between microcrack density and damage...