Engineering and Technology Journal

This article summarizes a new method for the capacity design of pipe networks using digital

computers.

The method is based on successive iteration technique.

The input data and output results of the computer program are simplified to enable wide uses of

the program. A sub-program is attached to the main one to provide an automatic graphical output of the design. hence reducing the engineers efforts in examining and drawing the results, and at the same time minimizing human errors. This sub-program is optional.

The units used with the program can be metric or British. a parameter is introduced to take care

of throughout the analysis, this choice.

INTRODUCTION:

Many engineers and researchers have been involved in the uses of computers on the analysis side of pipe networks Ref.7-9) while less work has been done on the design side. This may be due to the fact that engineers are generally concerned with the problems of exisiting networks, trying to find out how the system is operating and suggest modifications for improvement.

The increase in the number of new cities required in many developing countries, made it

necessary to give more thought to develop fast methods for the design of networks for water supply.

The function of the exhaust silencers is to reduce the noise level to an acceptable value to avoid the risk of ear damage when exposed to such noises for long periods. The drawback of the presence of asilencer is the high back pressure created due to restricting the gas flow or according to the pressure drop in the attenuating elements within the silencer. This investigation covers the theoretical formulae that guide the designer of a silencer, and which are derived from the theory of sound filtration. The silencers are classified according to the principle of muffling. The pressure drop along the exhaust system is presented also in the theory and experiment. The experimental results are obtained for both the acoustical and mechanical performance of each type of silencers with a comparison between them for the suitable choice of the silencer type. Obviously, the problem must be a compromise between the high noise levels and the high values of power loss due to engine quitening.

This is one of a series of papers interested mainly in the overall transient behaviour of integrated power systems. With a target of introducing the whole system in a synchronous machine-wise frame of reference: the subject paper is devoted for derivation of an expression for the long line as a machine-terminal constraint. Five versions for long line representation are proposed in an operational impedance matrix form. These can be left for further investigation for selection of the optimum, although the author recommends the fifth one Modification of line parameters due to inclusion of other distributed and lumped parameter series or shunt elements are discussed. Besides. available methods in literature for calculations of voltage and current vectors at any point along the line are given.

This is the second of a series of papers interested mainly in the overall transient behaviour of an integrated power system constituting a synchronous machine connected to a large network through a long line. After deriving an expression for the long line as a synchronous machine's terminal constraint in the first paper, this paper investigates the machine's electromagnetic transients involving line's short lived travelling wave effects. A digital model is derived for the study of the transient behaviour of the system involving the long line effects but excluding, the action of machine's automatic excitation regulator.