1991 Vol.4(2)
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1991, 5(2).
Abstract:
An exact mathematical model of side turning rotor type overspeed control mechanism (OCM) for small Scale horizontal axis wind turning is established. Using the optimum design method and programing to computer make the design of OCM quick and exact, thus taking a satisfactory effect.
An exact mathematical model of side turning rotor type overspeed control mechanism (OCM) for small Scale horizontal axis wind turning is established. Using the optimum design method and programing to computer make the design of OCM quick and exact, thus taking a satisfactory effect.
1991, 5(2).
Abstract:
This paper gives a special attention to the cause and conditions of low order resonance of elastic linkage, as well as the computation procedure for critical velocity.
This paper gives a special attention to the cause and conditions of low order resonance of elastic linkage, as well as the computation procedure for critical velocity.
1991, 5(2).
Abstract:
The hydrogen distribution ahead of crack tip in nickel single crystal was obtained quantitatively by Ion Microprobe Mass Analyzer (IMMA) with loading specimens. Two peaks of hydrogen concentration appeared in front of the crack tip, one peak localized in crack tip and another peak localized in some distance from the crack tip. It is concluded that the distribution of dissolved hydrogen with two peaks correspondences the distribution of strain field and stress field respectively, due to interaction of hydrogen with dislocation and hydrostatic stress.
The hydrogen distribution ahead of crack tip in nickel single crystal was obtained quantitatively by Ion Microprobe Mass Analyzer (IMMA) with loading specimens. Two peaks of hydrogen concentration appeared in front of the crack tip, one peak localized in crack tip and another peak localized in some distance from the crack tip. It is concluded that the distribution of dissolved hydrogen with two peaks correspondences the distribution of strain field and stress field respectively, due to interaction of hydrogen with dislocation and hydrostatic stress.
1991, 5(2).
Abstract:
The friction and wear properties of carbon fibre reinforced lead alloy composites under dry and lubricated conditions were studied respectively. Based on the eexperimental results, the effect of carbon fibre on wear process of lead alloy composite materials was analysed, and a new model of wear mechanism of metal matrix composites was proposed.
The friction and wear properties of carbon fibre reinforced lead alloy composites under dry and lubricated conditions were studied respectively. Based on the eexperimental results, the effect of carbon fibre on wear process of lead alloy composite materials was analysed, and a new model of wear mechanism of metal matrix composites was proposed.
1991, 5(2).
Abstract:
The tensile and stress-rupture properties of Ni3Al alloys containing various boron contents at 800℃and 850℃ have been studied. The results show that the tensile strength and rupture life can be improved by adding 0.52 to 1.37 at%B to Ni3Al, so do the tensile and rupture ductiles. The effect of boron is the most obvious when the alloy contains 1.37 at%B. If boron addition is too high, there are boride eutectic pricipitating in grains and at grain boundaries and the mechanical properties were severely degraded.
The tensile and stress-rupture properties of Ni3Al alloys containing various boron contents at 800℃and 850℃ have been studied. The results show that the tensile strength and rupture life can be improved by adding 0.52 to 1.37 at%B to Ni3Al, so do the tensile and rupture ductiles. The effect of boron is the most obvious when the alloy contains 1.37 at%B. If boron addition is too high, there are boride eutectic pricipitating in grains and at grain boundaries and the mechanical properties were severely degraded.
1991, 5(2).
Abstract:
Through the measurement of temperatures for pig iron, Mn-Fe, Si-Fe and the steel scrap in the cupola, we have given the distribution of the melting zones. The submelting zones are arranged by the melting temperature changes, they can be separated, connected or overlapped. This research has proved that the existance of the realistic procedural melting zone. So it establishes the basis for the application of the procedural melting zone's theory.
Through the measurement of temperatures for pig iron, Mn-Fe, Si-Fe and the steel scrap in the cupola, we have given the distribution of the melting zones. The submelting zones are arranged by the melting temperature changes, they can be separated, connected or overlapped. This research has proved that the existance of the realistic procedural melting zone. So it establishes the basis for the application of the procedural melting zone's theory.
1991, 5(2).
Abstract:
On the viewpoint that the solid-gas two-phase flow consists of subsystems: solid granules and gas, this paper analyses in greater detail the energy distributive relation of the solid and the gas subsystems and energy exchange between them under the circumstances of dilute phase. Suspension energy of the granule has been obtained by means of the fluid equation of energy. The new viewpoint has been advanced that suspension energy is the viscous dissipation function of fluid. And we have deduced the formula calculating pressure loss and the equation of motion of granule group in straight pipe from energy balance of the two subsystems, which explains some motion group in straight pipe from energy balance of the two subsystems, which explains some motion characteristics of the granules in the two-phase flow.
On the viewpoint that the solid-gas two-phase flow consists of subsystems: solid granules and gas, this paper analyses in greater detail the energy distributive relation of the solid and the gas subsystems and energy exchange between them under the circumstances of dilute phase. Suspension energy of the granule has been obtained by means of the fluid equation of energy. The new viewpoint has been advanced that suspension energy is the viscous dissipation function of fluid. And we have deduced the formula calculating pressure loss and the equation of motion of granule group in straight pipe from energy balance of the two subsystems, which explains some motion group in straight pipe from energy balance of the two subsystems, which explains some motion characteristics of the granules in the two-phase flow.
1991, 5(2).
Abstract:
The method of two-dimensional stochastic variables is adopted in statistical treatment of fatigue loads in this paper, and a two-dimensional probability distribution of fatigue strength is studied correspondingly. Based on these, a two-dimensional model of stress interference in strength is set up. If the factros of effect on fatigue strength are considered as stochastic variables, the method taking account of these factors in two-dimensional model of stress interference in strength is given, and the model is calculated by the Monte Carlo method.
The method of two-dimensional stochastic variables is adopted in statistical treatment of fatigue loads in this paper, and a two-dimensional probability distribution of fatigue strength is studied correspondingly. Based on these, a two-dimensional model of stress interference in strength is set up. If the factros of effect on fatigue strength are considered as stochastic variables, the method taking account of these factors in two-dimensional model of stress interference in strength is given, and the model is calculated by the Monte Carlo method.
1991, 5(2).
Abstract:
The basic principle of applying orthogonal electromagnetic fields to alloy melt in order to compensate the specific gravity difference between its components and to imitate microgravity condition, is described in this paper. Experiments have been terformed with the monotectic Zn-Pb alloys, system whose specific gravity difference between its components is quite large and whose components are easy to separate. It is found that the samples with homogeneous strutrue were able to be obtained when the parameters of electromagnetic fields were properly selected. Experiments and analyses have proved that this method is very useful to the studies of the solidification law and the technologies of making this kind of alloys.
The basic principle of applying orthogonal electromagnetic fields to alloy melt in order to compensate the specific gravity difference between its components and to imitate microgravity condition, is described in this paper. Experiments have been terformed with the monotectic Zn-Pb alloys, system whose specific gravity difference between its components is quite large and whose components are easy to separate. It is found that the samples with homogeneous strutrue were able to be obtained when the parameters of electromagnetic fields were properly selected. Experiments and analyses have proved that this method is very useful to the studies of the solidification law and the technologies of making this kind of alloys.
1991, 5(2).
Abstract:
The effect of an air-separator to improve the low flow rate performance of an axial flow fan has been discussed by the present paper. The influence of its geometric parameters and different locations ahead of the rotor on the performance of the air-separator was described. It is found that the air-separator is the most effective equipment for improving the unstabel characteristics of an axial flow fan. These investigations provide scientific basis for understanding the working mechanism and choosing the dimensions and structure of the air-separator of the fan.
The effect of an air-separator to improve the low flow rate performance of an axial flow fan has been discussed by the present paper. The influence of its geometric parameters and different locations ahead of the rotor on the performance of the air-separator was described. It is found that the air-separator is the most effective equipment for improving the unstabel characteristics of an axial flow fan. These investigations provide scientific basis for understanding the working mechanism and choosing the dimensions and structure of the air-separator of the fan.
1991, 5(2).
Abstract:
This paper deals with the theoretical analysis and experimental investigation of the dynamic behavior of a reversing process, which is controlled by the main pump itself in the closed-circuit. It is proven that the slow parameters in the reversing process have an obvious oscillation and a distributed feature. The study shows that the oscillation of parameters depends chiefly on the pattern of change of the flow rate Qp(t) of the main pump in the reversing process and can be restrained by means of properly selecting the Qp(t). In this papter, some circuit construction of the system is also discussed.
This paper deals with the theoretical analysis and experimental investigation of the dynamic behavior of a reversing process, which is controlled by the main pump itself in the closed-circuit. It is proven that the slow parameters in the reversing process have an obvious oscillation and a distributed feature. The study shows that the oscillation of parameters depends chiefly on the pattern of change of the flow rate Qp(t) of the main pump in the reversing process and can be restrained by means of properly selecting the Qp(t). In this papter, some circuit construction of the system is also discussed.
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