Aimed at the requirement for a fast-response expendable ocean temperature sensor, this paper presents a new design scheme for an optic fiber sensor. Ocean temperature sensors require high sensitivity and high response speed, which must be up to milliseconds. The fiber Bragg grating (FBG) temperature sensor with high sensitivity has been declared in the last decade, but its response speed has been rarely reported. In this paper, a method is proposed which is to package an FBG with a metal tube. The response time of this sensor is 48.6 ms, which is an order of magnitude greater than that of an ordinary optical fiber temperature sensor. Temperature sensitivity is 27.6 pm/°C and the linearity is up to 0.9999. In addition, the sensor can be less than 15 mm. It offers a new way to detect ocean temperature.

The characteristics of spray, combustion, and soot emissions of the diesel engine fueled with biodiesel-diesel blends and diesel are numerically simulated using AVL-FIRE software to illustrate the suppression effect of biodiesel on in-cylinder soot. The model was validated by comparison with experimental cylinder pressure and smoke for the baseline engine at rated power. The results indicate the spray penetration distance of the blends is farther than that diesel. Compared with that of diesel, the evaporated fuel mass of 10 and 20% (vol) biodiesel blending with diesel (donated as B10 and B20) are almost the same. The Sauter mean diameter (SMD) of the blends is greater than that of diesel from 11 before top dead center (BTDC) to 7 BTDC, and then SMD of the blends is less than that of diesel. The equivalence ratio of the blends is lower that that diesel except at the end of injection, leading to the tendency of sooting. The ignition timing advances as the percent of biodiesel in the blend increases, helpful to reduce soot formation. The soot mass fraction for B20 decreases by 35.5% at exhaust valve opening, while it for B10 and 50% (vol) biodiesel blending with diesel (B50), decreases by 14.9 and 14.1%, respectively. The mean soot diameter and particle number of diesel give the bimodal distribution while those of the blends do trimodal distribution. V C 2014 American Institute of Chemical Engineers Environ Prog, 34: 282-288, 2015

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