One of the principal purposes in computer application for process control is the dynamic performance improvement using computer oriented control algorithms.
This type of control is classified into“Regulatory Control.”
Moreover, the“Advanced Control Theory”is expected to help this control requirement. Because of the marine steam plant is a typical heat and mechanical process, above mentioned application of computer is considerable for this plant.
In this article, the results of simulation study for the“Model Reference Adaptive Control System”, which is one of the“Advanced Regulatory Control Concepts” applied to a marine main boiler system, is introduced with the numerical simulation.

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The structure of the gas flow in cross-flow tube banks is an important factor in analyzing vibration problems including the gas column resonance, the Karman vortex excitation, and the fluid-elastic mechanism. In this paper, the structure of gas flow is investigated by means of the visualization technique and the hot wire anemometer from the viewpoint that the flow in tube banks can be treated as a complex Karman vortex flow. The results obtained by this experiment are as follows;
1. The strouhal number is strongly dependent on the size of the vortex formation region and therefore varies widely with tube spacings.
2. Several flow patterns, such as that in which the Karman vortices are not formed in tube banks, and that in which the gas flow deflects due to the Coanda effect, were identified and explained.
By using the Strouhal number obtained here, the result of a survey on the actual exhaust economizers in Diesel ships was analyzed. It was found that the present day practice is not immune from the danger of the gas column vibration.
Experiments were also carried out on the fluid-elastic vibration of tubes in a single row tube banks. It was found by this experiment that the fluid-elastic vibration has its own field of danger. The relation between the critical velocity and the tube spacing was obtained.

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For the purpose of getting compact marine boilers, a once-through supercharged boiler having the steam capacity of 15 t/h and the supercharging pressure of 2.8 ata was made and the characteristics required of the boiler when it is put to practical use were obtained through experiments. Furthermore, in order to realize perfect automation of this boiler plant, various kinds of automatic operations and control experiments by means of a control device where a mini-computer was employed were carried out. A hardware system and a fundamental software system of the direct digital control system of the boiler is also described in this report.

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Conventional two-drum marine boilers much used today have many generating tubes, so called main tube bank, where the heat is absorbed by convectional heat transfer. The vibration problems of these tubes, however, should become much more serious matters as the marine boiler become larger. Therefore if we could cut off all these convectional generating tubes and the energy should be absorbed at the economizer parts, it is possible to design such a boiler as permits evaporation at its economizer.
In this paper, steaming economizer feasibility has been studied within the limits of the standard design conditions of conventional marine boilers and an investigation has been made about the effects of a steaming economizer upon the responses of pressure and water level in the steam drum, comparing with the conventional type boilers. An experiment was carried out with the steaming economizer type boiler installed for turbine test in workshop, and the results of the experiment have been studied for comparison with theoretical analysis. is.
As a result the steaming economizer will present no operating problem and the following have been found.
1. The outlet steam quality of a steaming economizer is less than 25 percent, within the limits of the standard design condition of conventional type marine boilers. The response of steam drum pressure and water level, therefore, are not very different from those of the conventional type boilers, and the partial modification of the analysis for the conventional type boiler makes it possible to analyze and explain relatively well about the dynamic response obtained from the experiments.
2. The fluctuations of water level, however, are smaller in the case of steaming economizer for reasons such as its smaller volume of a boiler with two-phase flow region and possibility of its design at a high void fraction.
3. The pressure response in the steaming economizer type boiler is faster than the conventional one, because the heat quantity in the evaporating tubes is much reduced.
4. The equation to give pressure response can be most suitably arranged on the basis of evaporation in which the heat quantity absorbed at the steaming economizer is as well taken into consideration.

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The outlines of the boiler monitoring system of the KINKO-MARU are introduced and the feasibility and various problems of the system are discussed from the standpoint of utilizing a computer in the rational maintenance of marine propulsion plants. The explanation are based on data collected from actual observations.

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