1. Abstract page 2
2. Introduction page 2
3. How the Process Currently Works page 3
4. Two Phase Flow page 4- 6
5. Flow Patterns page 7- 8
6. Interfacial Mass and Energy Exchange page 9
7. Two Phase Flow in Horizontal Pipes page 10
8. Pressure Drop page 11
9. Future Work page 11
10. Timetable page 12
11. References page 13
The petro-chemical industry employs a wide range of engineers from many different disciplines to design, problem solve, test, simulate and build, among other tasks, to bring many petroleum/oil based and other chemically manufactured products and to the customers who require or desire them. One of the many problems engineers face in this process is the transport of materials in either a liquid or vapour/gas state. The most common and widely used means of transporting substances in these states is through pipes. Whether be pipes that serve households and business with gas and water to a pipe that acts as an outlet for steam release from a boiler piping is an important transport tool in the modern world, none more so than in the petro-chemical industry. The later of the previous examples will be the focus of this project, examining whether or not conservative estimates in the calculations involved are appropriate or whether through more intense and complicated calculations, the expanded data could be of beneficial use to the petro-chemical industry.
When calculating allowable stresses in piping systems, very conservative values are applied in the simulation testing stage currently within the petro-chemical industry. These values are applied as forces to each bend in a system in simulation to test whether or not the forces will exceed the allowable level. Essentially the force entering the system is the same force applied to each bend, or node, in the system. Now although this system accomplishes what it is set out to do, after speaking to engineers working in the industry, it is believed that this cannot be true as many other factors, not taken into account, would lead to pressure drops in the system such a friction, different flow types and the effects of bends in the system. The aim of this project is to calculate these given losses to obtain more accurate force values on the nodes and to run simulations using these values to ascertain whether or not this system of calculation would be beneficial or negligible in piping systems. The project will be based on a piping system that deals with steam being released from a boiler to be released downstream, away from the boiler itself. Research is to be conducted, based on two phase flow and on pressure drops in piping systems. This information will be used to obtain accurate calculations involving the pressure drops and will then be inputted to Seasar II piping software to compare the industrial standard to this currently unused system of calculation.
3. How the Process Currently Works
This diagram shows how diagrammatically the forces of the fluid/vapour affect the pipes that it is travelling through. The calculation sheets on the next page show where the annotations on the drawings are derived from. These calculations will be inputted into the software Seasar II which will run a simulation under these condition (with additional data on materials and fittings used) and will produce results indicating whether the system is safe or will fail, as well as giving an indication of by how much. This example has already been simulated hence the authors note indicating the percentages of allowable stress in the pipe. As can be observed from the calculation sheets and drawing, losses due to friction, energy and pressure drop have not been taken into account. The values for the forces entering the respective pipes through the relief valves have been applied...