In the general combustor, fuel and air are fed separately and combustion occurs primarily within a spacially limited zone. Turbulent mixing rates in such a system have important effects on the emission of pollutants such as unburned hydrocarbons and soot. The main purpose of the present paper is to investigate on the control of the soot emission due to the different swirling intensities of combustion air flow. The blades of the swirl generator can change continuously from 0° to 70° (θb : swirl angle) in order to increase the tangential velocities. Characteristics of soot emission are measured in propane/air diffusion flames of two typically different combustor of parallel and enlarged types paying special attention to the roles of gas temperature on the behavior of soot formation and decomposition in the flames. Profiles of soot concentration together with gas temperature and entrainment rate of O2 are measured in all flames. When the swirl angle (θb) is raised, both of the soot formation and decomposition rates increases. The larger angle of the θb results in the lower exhaustion of soot. However, in the enlarged combustor, finally exhausted soot concentration in the θb=70° becomes much higher than that in the smaller angle θb=60° for the decay of soot decomposition in the down-stream.
A marine diesel engine diagnostic system appears to be necessary because of the following considerations; 1) an uneconomical maintenance schedule 2) a less frequent and shorter overhaul period 3) a difficulty to recruit the skill personnel. The object of this work is to develop some new diagnostic system for marine diesel engines by some acoustic sounds analyses, in particular with regard to the reliability, simplicity and cost of analyzing system and the treatment of information. But it is very difficult because of the engine's complex movements and the variation in its heat cycle of internal combustion. This paper discusses the some kinds of analyses (the following three methods A, B and C) of the acoustic sounds due to changing load on an uniflow type marine diesel engine. The method A (time series analysis) having a band-pass filtering can give the history of time series analysis and some basic informations of pattern recognition for the detection of engines abnormal conditions. The method B (power spectrum analysis) is widely used to analyze complex time series data. The abnormal signals will be able to be detected as the deviation of the power spectrum levels of some frequency components comparison with normal ones. The method C (three dimensional display) using the color pattern corresponding the above levels can show the informations with the time history for the power spectrum of many kinds of the running conditions. The above three methods can offer some effective informations and basic data to a diagnostic system for marine diesel engines. Especially the method C should be noticed to give both the early recognition of the irregular time history and the detection of abnormal signals by color pattern.
Recently, damage reports of packaged air conditioner due to corrosion of tubes have been remarkably increasing. Judging from the condition of damaged coolers, the corrosion is caused by overvelocity of cooling water through tubes. This paper gives some countermeasure to avoid overvelocity.
This paper is an excert from the manuscripts written by the marine auxiary equipment subcommittee of the marine Engineering history committee of the MESJ. The manuscript was completed after 10 years of hard wark. But has not yet been pubbished because of various aduerse conditions. This paper is one of the serial papers which will appear in this Journal twice a year to introduce the content of the manuscript to menbers of MESJ. This paper are consist of Deck machinery, Steering gear systems, and refrigerator and air conditioning systems. Marine machinery equipment developed according to ship building progress. They were almost imported from foreign country in Meiji and Taishou Era, but a some of large sized passenger vessels used the imported products on account of a lack of reliability in Japanese products. The marine machinery equipments developed rapidly own design and unique products by the World War II.