In recent years, an increasing awareness of the shortness of raw materials has led to an improved utilization of the energy input in thermal processes. Utilization of the heat generated in such processes and machinery can improve the overall efficiency of the latter and converse raw materials. In particular, combustion engines have a poor overall efficiency due to the high-temperature exhaust gases they produce. The classical Clausius-Rankine process can be applied to such machines in order to utilize the heat generated so as to provide turbocharging of the latter. The design of such a Clausius-Rankine process in connection with a newly developed steam turbine based upon the Pelton principle is presented. In this design, particular value is placed upon the small size of individual units and a comparability with actual thermodynamic conditions in combustion engines.
A method for detection of weak turbo-drill rotating speed signal is proposed the basis of theoretical analysis and field test of the interference in mud channel through which the signal is transmitted from downhole to the surface. This method uses an adaptive noise canceller (ANC) to eliminate the strong pump interference and determines the speed through power spectrum peak detection. The principle of ANC is peak detection. The principle of ANC is explained in detail. Computer simulation and laboratory tests have demonstrated the feasibility of a signal processor thus constructed. Introduction Turbodrill rotating speed considerably affects the drilling rate, and hence the overall efficiency. Since turbodrill works downhole under very high temperature and pressure, it is rather difficult to measure pressure, it is rather difficult to measure its rotating speed in real-time. A signal generator suggested by Maurer Engineering Inc. is used to produce the turbodrill rotating speed signals. The generator consists of a set of turbine rotor and stator with their turbine blades blocked approximately 40% to produce a pressure pulse in the drilling mud flow for each revolution of the turbodrill. Pressure pulses are transmitted through the mud channel in the drill pipe to the surface where they are detected by a pressure transducer. The frequency of the pulse signal is a direct measure of the turbine rotating speed. This signal generator is easy to make almost without changing the structure of the turbodrill. However, the rotating speed signal is extremely weak at the wellhead compared with the noise in the mud channel. The key to the rotating speed measurement lies in the accurate detection of the frequency of the weak signal in a strong noise. An adaptive noise canceller (ANC) is used to eliminate the interference within the useful frequency range, and the rotating speed can be determined through power spectrum peak detection. The above-mentioned method peak detection. The above-mentioned method makes it possible to develop a kind of low cost, reliable and accurate MWD turbodrill tachometer. INTERFERENCE IN MUD CHANNEL In the mud channel there exists strong pressure pulsation caused by the pressure pulsation caused by the reciprocating action of the pump plungers. The period of the fundamental harmonic of this period of the fundamental harmonic of this interference Tr is 1/6 of the revolution period of a typical oilfield triplex period of a typical oilfield triplex plunger pump Tp. For a pump speed of 120–160 plunger pump Tp. For a pump speed of 120–160 rpm, the frequency of the fundamental harmonic of this interference fr=1/Tr=12–16 Hz. The amplitude of the interference can reach 0.8–1.0 MPa, about 10 times stronger than that of the signal. The characteristics of the signal and the interference in the mud channel were measured and studied on a testing well in Zhongyuan Oilfield. The depth of the well was about 1,000 m. The turbine used was 6.5 in. in diameter with 90 stages. A 3NB-80 triplex plunger pump was used with fresh water as drilling fluid. During the test, the pump speed was 148 rpm. The average pressure at the wellhead was about 1.4 MPa. pressure at the wellhead was about 1.4 MPa. P. 413
An inexact reconstruction technique (IRT) has recently been developed which allows a 3-D object to be reconstructed using a very limited number of views. The object is assumed to be adequately represented by a binary (Boolean) distribution of mass.This method has been successfully applied to a biological object using only three views at 45° intervals. The IRT method has been improved with regard to speed and accuracy and has been extended to the special case where three mutually orthogonal views can be obtained.
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