Kenji Fujikake

LDA measurement of fuel droplet sizes and velocities in a combustion field

Abstract Laser doppler anemometry was applied to simultaneous measurement of fuel droplet size and its velocity in two kinds of continuous mini burners. Droplet size was determined from the scattered light intensity ( Ip ) and number of Doppler burst waves ( N ) that was required to correct the effect of different particle trajectories in the measuring volume. Prior to the experiments, calibrated lines for representative droplet diameters were made with regard to Ip and N . The two burners had different types of air assist fuel injectors. One had the injector with the swirler which provides assist air with a tangential velocity component. Another had the injector without the swirler and the air had no tangential component. These combustion flow fields were then compared. Downstream of the injector in both burners, Sauter mean diameter (SMD) varies as follows. In a combustion field it is larger than that in unburned condition and reaches a maximum, after which it decreases until all the droplet evaporate rapidly. These features agree with the results of numerical calculations for fuel droplet evaporation. In combustion fields, the SMD of the droplets from the swirler injector is about 10 μm smaller than that from the no-swirler injector. Therefore the droplets evaporate earlier than those from the no-swirler injector in the burner. Temperature measurement with a thermocouple shows that the temperature in the swirler-equipped burner is about 100 K higher than that in the swirlerless burner. The swirler provides a circular cone extension of droplets with high densities and high velocities. A higher temperature zone is formed just outside the cone end.

Measurement of Air Velocity Distribution and Airflow Rate Through Radiator in an Automobile

An air velocity sensor has been developed to measure the air velocity distribution at a radiator front. And, an air velocity distribution meter system for a radiator has also been developed, which can display a radiator airflow rate, a constant air velocity line graph and a perspective representation graph, by use of many air velocity sensors mounted on the radiator front and a computer for data processing. The airflow rate and its distribution under various running conditions for passenger car (1.8 script l) has been measured with the air velocity distribution meter. /SASI/

AUTOMOTIVE MIXED FLOW FAN WITH GUIDE VANES ON BLADE SURFACES

We have developed a simple and lower cost mixed air flow fan with guide vanes on the blade surfaces for use in automotive engine cooling. Through investigation of the fan performance and flow visualization, the axial and radial flow produced by this fan proved to be most suitable and efficient for engine cooling. The improved efficiency and increased air flow provided by this fan contribute to reduction of specific noise level and power consumption as compared to conventional fans.

A NEW FEEDBACK CARBURETOR WITH AIR JET COLLISION CONTROL

A new type closed loop A/F control carburetor has been developed. In the carburetor, an air jet, a by-pass stream of an intake air flow, is made to collide with a fuel flow to suppress the flow rate. Studies were made of the basic features of the method such as fuel controlling capability and the factors affecting it from phenomenological consideration and schlieren observation. For comparison, three types of carburetors were prepared for the combination of main and idle fuel circuits. In driving mode tests on a dynamometer, a new carburetor which employs the new method for the main fuel circuit, provides 30% lower emission level than an air bleed control carburetor. Higher controlling frequencies were obtained for the new carburetors. The high controllability of the air jet collision control method is attributable to the smaller fluctuation in both the controlling air and the spouting fuel.