A new model for the design of the city gas distribution network has been presented. On the basis of mass flow rates and pressure balances a nonlinear system of equation is obtained. A method for solving the latter is outlined which gives accurate results. Also, this method, when compared to the other accessible ones, takes less computer time. Finally in this method the actual length of netw...

An analytical investigation and conceptual design of a disk-shaped asymmetric heat pipe is presented in this work. Using the conservative formulations for the steady incompressible vapor and liquid flow for a disk-shaped heat pipe, an in-depth integral analysis is applied. Analytical results for the asymmetric vapor velocity profile, the vapor and liquid pressure distributions, and the vapor te...

We study the flow of two immiscible fluids of different viscosities and equal density through a pipe under a pressure gradient. This problem has a continuum of solutions corresponding to arbitrarily prescribed interface shapes. The question therefore arises as to which of these solutions are stable and thus observable. Experiments have shown a tendency for the thinner fluid to encapsulate the t...

When a fluid enters a rotating circular pipe, an angular momentum or swirl boundary layer appears at the wall and interacts with the axial momentum boundary layer. In the centre of the pipe, the fluid is free of swirl and is accelerated due to boundary layer growth. Below a critical flow number, defined as the ratio of average axial velocity to circumferential velocity of the pipe, there is flo...

This study numerically investigates turbulent pipe flow driven by a pulsating pressure gradient. While studies of laminar and turbulent pulsatile pipe flow with a single mode of oscillating pressure gradient have been carried out extensively, there is scarce literature on pulsating pressure gradients with multiple temporal Fourier modes. In many real-life engineering applications, for example, ...

We consider the problem of water flow in a pipe of constant cross sectional area due to an elevation change between the pipe inlet and outlet. The flow is assumed to be steady and the pipe flows full at all cross sections. The application is the design of a single leg of a water distribution network that is fed by one reservoir (the “source”). There are many references for this type of design (...

Hazen-Williams equation is used widely by irrigation systems’ designers due to its simplicity.However, Darcy-Weisbach equation is more accurate and reliable. The accuracy of the latter is due to its friction coefficient, which depends on both flow characteristics and pipe surface state. On the other hand, Hazen-Williams’ coefficient (C) depends only on pipe substance and age. A comparative anal...

This study presents results from detailed experiments of the two-phase pressurized flow behavior during the rapid filling of a large-scale pipeline. The physical scale of this experiment is close to the practical situation in many industrial plants. Pressure transducers, water level meters, thermometers, void fraction meters and flow meters were used to measure the two-phase unsteady flow dynam...

AIMS Stagnation is widely believed to predispose water systems to colonization by Legionella. A model plumbing system was constructed to determine the effect of flow regimes on the presence of Legionella within microbial biofilms. METHODS AND RESULTS The plumbing model contained three parallel pipes where turbulent, laminar and stagnant flow regimes were established. Four sets of experiments ...