Transient characteristics of heat exchangers have been studied and developed by Masubuchi. And it seems that the discussions for these problems are completed, but those results are far from actual application for some cases. In this paper, vertical high pressure feed water heaters which are equipped in the steam propulsion plant are considered, because these responses influence the boiler feed water temperature directly. The heating medium in a shell side presents character changes, i.e. desuper heating-steam, condensing-saturated vapour, and drain cooling-drain. This means the heat exchange model for it is very complicated and makes difficult to take fundamental relations. The heat exchange model here is very simplified and represented only by condensing model including all other sections. The theoretical analysis is tried and developed especially with the aid of the results by Hotta and Imaeda. As the result of the theoretical analysis and on board tests, followings are concluded. 1) The transfer functions which describe the transient responses are known and confirmed. 2) The response is much depend upon the characteristics of associated final control elements rather than one of the heat exchanger itself.
Safety design of the boil-off gas burning system is required for safety transferring and safety burning of the boil-off gas led from the cargo tank to the main boiler as a fuel. Here the essential design conditions and problems on the safety design are enumerated and among these problems the characteristics of boil-off gas/oil combined firing are picked up to investigate. The firing test was carried out in a test furnace by natural gas using two kinds of actual dual fired burners, one of ring type gas nozzle and the other of multi-lance type gas nozzle. The dual firing characteristics are got from the above test and the minimum considerations for safety design of the dual firing system from a firing characteristics point of view are obtained on the following items: (1) Safe combustion ratio of fuel oil and fuel gas including consideration for minimum quantity of either fuel oil or fuel gas. (2) Excess air supply ratio at each stage of normal operating, load changing and starting of dual firing. (3) Consideration for keeping stable combustion and for protecting furnace from rapid rising of the internal pressure of the furnace during a rapid load change. (4) Consideration for keeping safe combustion even if a great deal of inert gas is mixed with fuel gas. (5) LPG/N2 mixture gas having equivalent firing characteristics and flame stability to methane gas, which can be substituted for methane gas in the shop test of dual firing.
Today, how to treat the oily bilge in engine room is one of the matters concerned with marine engineers. In this paper, it is reported of the designing concept and detailed experimental results of the bilge treatment system provided on the thirteen ferry boats of Japanese National Railway, now engaging in the transportations of passengers and wagons between Hakodate and Aomori. During the past seven years, the system has been modified several times after our experimental studies and now the system works satisfactorily. By our experience, removing the oily dust contained in the oily bilge on the upper streams of a bilge separator is the most important matter in this system, especially in the case of using the fine bilge separator. In this regard, we have found that gravels of 5-10 mm packed into a strainer are useful for catching oily dust. In conclusion, we have to report that in order to get satisfactory operation of a bilge separator, careful design and control of pre-treatment system for oily bilge water is quite important.
Having visited 13 firms in Europe in July 1976, the author describes his findings in the fields of Stirling engine developments, measuring methods and instruments, internal combustion engine developments and bearing research.