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Showing papers in "Jsme International Journal Series B-fluids and Thermal Engineering in 1958"


Journal ArticleDOI
TL;DR: In this article, the authors introduced the equations of the above-mentioned theory, and some calculations are carried out for a ring, the surface profile of which consists of the quadratic and the parallel line.
Abstract: Near the T.D.C. of the expansion stroke of the engine, the piston-ring speed is 0 and its load and temperature reach a maximum. If it were based ob the steady-flowhydrodynamics, the oil film between the ring and the cylinder would have to be broken down. In practice, however, the fluid-film lubrication is achieved in the high speed region. These phenomena can be explained by a dynamical theory of the hydrodynamics, the piston-ring speed and load vary so extremely that the oil-film thickness changes rapidly, and this rate of change in the oil-film thickness generates a load carrying capacity by the squeeze action. This paper introduces the equations of the above-mentioned theory, and some calculations are carried out for a ring, the surface profile of which consists of the quadratic and the parallel line.

98 citations



Journal ArticleDOI
TL;DR: In this paper, the frequency in vibration of rectangular plates with circular holes is studied and the displacement is expressed in terms of the products of bar-solutions which satisfy the boundary conditions of plate.
Abstract: The frequencies in vibration of rectangular plates with circular holes are studied. The method is due to Ritz and the displacement is expressed in terms of the products of bar-solutions which satisfy the boundary conditions of plate. The kinetic and potential energies are given in the cases of clamped-clamped, clamped-free and clamped-supported ends. Numerical calculations are carried out in the case of the plate of which all edges are fixed and with a hole in centre. Experimental data are also given in the above mentioned case in which the ratio of edge lengths is 1/2 and the agreement with calculations is good.

25 citations



Journal ArticleDOI
TL;DR: In this paper, the authors studied the law of similarity with respect to the flow of non-Newtonian fluids in pipe lines by using the equations of motion and extended Fanning's formula of pressure losses in pipe line.
Abstract: The author studied the law of similarity with respect to the flow of non-Newtonian fluids in pipe lines by using the equations of motion. Secondly, the Fanning's formula of pressure losses in pipe lines was extended to the non-Newtonian flow. Moreover, the coefficients of pipe friction losses for turbulent flows were evaluated. When the coefficient of pipe friction and the Reynolds number in a wider sense are used, the characteristics of non-Newtonian flows in pipe lines are approximately equal to those of Newtonian flows.

21 citations


Journal ArticleDOI
TL;DR: In this paper, the effects of cycle frequency on the fatigue strength of carbon steels under simultaneous corrosion in tap water and saline are studied and the cumulative damage criterion is found to be applicable.
Abstract: The effects of cycle frequency on the fatigue strength of carbon steels under simultaneous corrosion in tap water and saline are studied. The stress σc given under corrosion fatigue increases to σck owing to the notch effect of corrosion pits. At a certain repetition number of N, σck reaches the fatigue strength σ of the same repetition number in air and fractures by corrosion fatigue occur. And the condition of fracture is given by Eq. (5), under consideration that the corrosion effect k increases with time and σ is a function of N alone. Various experimental results are well explained by this criterion. This conception is further extended to the corrosion fatigue combining the static pre-corrosion and also changing cycle frequencies during runs. For the corrosion fatigue under varying stress amplitudes the cumulative damage criterion was found to be applicable. And so the strengths of corrosion fatigue under wide stress conditions may be known.

19 citations


Journal ArticleDOI
TL;DR: In this article, the authors investigated the desiging factors of the bearing concerning the clearance, the restrictor, the pocket and supplying fluid pressure taking into consideration the conditions of the best dynamic stability, the maximum load capacity and the minimum power consumption.
Abstract: The load capacity of hydrostatic bearings can be increased by making a pocket which keeps effective fluid pressure on the bearing surface, and their dynamic stability can be improved by arranging a suitable restrictor like a capillary or an orifice which corresponds to the bearing dimensions and the optimum clearance in the fluid supply-line. In this report, concerning three types of thrust bearings which have the bearing surface of sphere, disc or cone, the theoretical solutions of rressure distribution, quantity of flow, load capacity and power consumption are obtained. Depending on the above solutions, it is clarified that the bearing clearance should be determined by the dimensions of the restrictor. Therefore, the desiging factors of the bearing concerning the clearance, the restrictor, the pocket and supplying fluid pressure have been investigated taking into consideration the conditions of the best dynamic stability, the maximum load capacity and the minimum power consumption.

15 citations


Journal ArticleDOI
TL;DR: In this article, a strain gauge and a dynamical gear testing machine have been used to measure dynamic loads on gear teeth, and the results of the analyses show that measured dynamic loads or measured dynamic stress cycles nearly coincide with calculated results respectively.
Abstract: In order to measure dynamic loads on gear teeth, a strain gauge apparatus and a dynamical gear testing machine have been made. The strains at the tooth flank, where a strain gauge is attached, are observed and dynamic loads are measured by comparing dynamic strains with static strains. Dynamic behaviors of mating gears are analysed as those of a vibration system which is constructed by the masses of the pinion and gear and the combined stiffness of the mating teeth. Here, the variations of combined stiffness of mating teeth, tooth errors and contact ratio etc. are analysed. The results of the analyses show that measured dynamic loads or measured dynamic stress cycles nearly coincide with calculated results respectively.

13 citations


Journal ArticleDOI
TL;DR: In this article, the cutting direction angle of 40°∼50° is the most suitable for fine-grained abrasive stones and the cutting speed of 40 m/min is the best.
Abstract: For the purpose of inquiring into the cutting mechanism of fine-grain abrasive stones in the honing, an experimental research has been carried out with an external honing apparatus. Concerning the cutting speed, the best cutting efficiency is obtained at a cutting speed of 40 m/min. The cutting direction angle of 40°∼50°is the most suitable, and the cutting direction angle is the most decisive factor in the cutting mechanism of honing. As to the bond hardness, it is suitable to use the harder stone. Comparing the honing with the superfinish, the most suitable values of cutting direction angle and cutting speed are same in both cases. But the cutting efficiency of superfinish is 5∼10 times that of honing, and the stone wear per unit amount of stock removal of honing is slightly smaller than that of superfinish.

9 citations


Journal ArticleDOI
TL;DR: In this article, the flow through the passage of rotating impellers with single and double shrouds (full shrouds) has been studied experimentally by means of a test rig, so designed that it is possible to measure directly the relative velocity, flow direction, total and static pressure on several points in the passage while the impeller is rotating.
Abstract: The flow through the passage of rotating impellers with single and double shrouds (full shrouds) has been studied experimentally by means of a test rig, so designed that it is possible to measure directly the relative velocity, flow direction, total and static pressure on several points in the passage while the impeller is rotating. On the other hand, the theoretical analysis was made under the assumption of two-dimensional potential flow, and the calculated results are compared with the measured results in terms of relative velocity under the given operating conditions. The velocity distribution and the flow direction obtained in the experiments indicate that secondary flows in the boundary layer tend to shift the low-energy air toward the negative surface (Suction surface) of the blade in the passage. In case of single shrouded impeller, there is observed a counter effect along the casing surface apparently caused by the leakage through the clearance space between the blade and the casing. This results in a voltex flow in the passage. It can be concluded that the secondary flows consequently dominate the flow condition, and make it so complicated that it is impossible for us to conjecture it by means of theory.

6 citations


Journal ArticleDOI
TL;DR: In this paper, the influence of the roughness of the inner surface of pipe upon the pressure drop due to friction in two-phase flow of the mixture of air and water in inclined and vertical pipes was investigated.
Abstract: In this paper, the author has experimentally investigated the influences of the roughness of the inner surface of pipe upon the pressure drop due to friction in two-phase flow of the mixture of air and water in inclined and vertical pipes. The results of investigation may be summarized as follows : (1) For the wide range of roughness, the ratio of pressure drop is written as follows : ΔPTP/(ΔPw)=(1-φd)-z where ΔPTP : pressure drop due to friction in two-phase flowing, ΔPw : that in water alone flowing, φd : dryness fraction, Z : value depending on the roughness and inclination angle of pipe. (2) The variations of the values of Z due to the roughness of inner surface and the inclination angle of pipe have been made clear. (3) The influences of roughness and inclination angle upon the ratio of the coefficient of friction are presented.

Journal ArticleDOI
TL;DR: In this paper, the authors calculated the ideal delivery, its pulsation factor and the variation of the trapped volume and found that the internal gear pumps are more excellent than the conventional external gear pumps in the following points, (1) the pulsations of the delivery and the delivery pressure are small, (2) the variation is small, and there is no extreme pressure rise nor decrease in this space with no relief groove.
Abstract: Concerning the involute profile internal gear pump, the author calculated the ideal delivery, its pulsation factor and the variation of the trapped volume. And these characteristics were verified by his experiment. As a result of this research it was found clearly that the internal gear pumps are more excellent than the conventional external gear pumps in the following points, (1) the pulsations of the delivery and the delivery pressure are small, (2) the variation of the trapped volume is small, and there is no extreme pressure rise nor decrease in this space with no relief groove.

Journal ArticleDOI
TL;DR: In this paper, the authors carried out theoretical and experimental investigations in order to ascertain precisely how the external pressure exerted on a hoisting drum by multi-layers of rope wound around it under tension increases as the number of rope layers is increased.
Abstract: The writers of this paper carried out theoretical and experimental investigations in order to ascertain precisely how the external pressure exerted on a hoisting drum by multi-layers of rope wound around it under tension increases as the number of rope layers is increased. Experiments were performed on model drums by winding ropes under constant tension and the circumferential strains produced inside the drum shells were measured. The number of layers was increased up to eight. As far as the research extended, the experimental results coincided well with the theory of the authors. The ratio between the increase in the external pressure on the hoisting drum and the number of rope layers grew the larger as the rigidity of the drum increased and the modulus of elasticity of the rope decreased. Conversely, the smaller the rigidity of the drum and the greater the modulus the smaller was the ratio. The ratios of Mr. Waters which have generally been adopted are smaller than those of the authors and are on the dangerous for the designing of hoisting drums.

Journal ArticleDOI
TL;DR: In this paper, the authors study the process of change of surface roughness and obtain a transformation law from distribution of the pressed surface profile to that of the initial profile, using the results about the contacting ratio, the gap between two contacting surfaces and the coefficients of changing roughness determined by combination of two materials of the surfaces, etc.
Abstract: In the study of contact of two surfaces, surface roughness is especially important. So first it is necessary to study how an initial roughness changes under the given conditions. And distribution constants of the profile in terms of an estimation of roughness are useful. We press two surfaces each other under the given conditions, study the process of change of roughness and obtain a transformation law from distribution of the pressed surface profile to that of the initial profile. Using the results, we consider about the contacting ratio, the gap between two contacting surfaces and the coefficients of changing roughness determined by combination of two materials of the surfaces, etc.

Journal ArticleDOI
TL;DR: In this article, the problem of steady one-dimensional heat transfer between two parallel plates in the rarefied gases was treated, and the moments of the distribution function were derived from the Maxell-Boltzmann equation.
Abstract: Fundamentally, the properties of rarefied gases must be deduced from the Maxwell-Boltzmann equation. We will treat the problem of steady one-dimensional heat transfer between two parallel plates in the rarefied gases. H. Grad expressed the distribution function of the gas molecules in the Hermite polynomials. This method, however, cannot satisfy the boundary conditions that the distribution function is discontinuous between incidental molecules and reflecting ones. Then we will divide the distribution function for incidental molecules and for reflecting ones separately, which have different coefficients. Using these distribution functions, we get four equations of the moments of distribution function and three equations can be obtained from the Maxell-Boltzmann equation. From these seven equations we can solve the temperature distribution between two parallel plates in the rarefied gases as the function of the distance from the wall. And we get the relation between wall temperature and heat flux vector.

Journal ArticleDOI
TL;DR: In this paper, the transient behavior of 0.14 per cent carbon steel, which appeared by a partial removal of applied stress at the stage of secondary creep, was studied at 450°C.
Abstract: The transient behavior of 0.14 per cent carbon steel, which appeared by a partial removal of applied stress at the stage of secondary creep, was studied at 450°C. The strain rate after the partial reduction of stress was found smaller than the true steady creep rate for the reduced stress, however it gradually increased with time and appeared to tend to the steady creep rate. It was also found that the higher was the applied stress before the stress reduction, the lower rate of strain appeared after the reduction at a given strain and the longer period was necessary before the strain rate reached the steady creep rate. These behaviors were ascertained to be well interpreted by the authors'theory of the plastic deformation of metais at high temperatures.

Journal ArticleDOI
TL;DR: In this paper, the problem of bending a clamped or simply supported elliptic plate subjected to a concentrated load at an arbitrary point is treated. And rigorous solutions in a form of infinite series are obtained by means of elliptic coordinates and by expanding the particular solution into Fourier series.
Abstract: We treat the problems of the bending of clamped or simply supported elliptic plates subjected to a concentrated load at an arbitrary point. The rigorous solutions in a form of infinite series in these cases are obtained by means of elliptic coordinates and by expanding the particular solution into Fourier series. Moreover, a clamped elliptic plate under a concentrated load in the center is treated as a numerica1 example.



Journal ArticleDOI
TL;DR: In this article, it was shown that unless just the right amount of air is admitted, instead of reducing vibration, a large amount of draft head is destroyed, and, conversely, vibrations are increased.
Abstract: Our experimental study revealed that the severest vibrations in the draft tube of water turbines can be eliminated or greatly reduced by the admission of air into the draft tube, but unless just the right amount of air is admitted, instead of reducing vibration, a large amount of draft head is destroyed, and, conversely, vibrations are increased. To verify this fact, we used models of draft tubes. We obtained the relations among amplitude of vibration, flow ratio of air to water, draft tube efficiency, and ratio of circulatory component to axial component of water. Here the optimum amount of water to be admitted is studied and results are presented graphically.

Journal ArticleDOI
TL;DR: In this paper, the main results obtained may be sumarized as follows : 1) Resistance coefficient in turbulent flow region tends to a certain value with increasing Re for rough surface, and for a certain small value of clearance, coefficient Cf takes a minimum value.
Abstract: Though numerous studies of disc friction of smooth surface were already carried out, but the detail discussions of disc friction of rough surface have not yet been performed. Experiments were carried out for both cases of discs with smooth surface and rough surface, consisting of sand-grain of various size and shape. The main results obtained may be sumarized as follows : 1) Resistance Coefficient Cf in turbulent flow region tends to a certain value with increasing Re for rough surface. 2) For a certain small value of clearance, coefficient Cf takes a minimum value. 3) Resisting moment of cast-iron disc is equal to that of the disc with rough surface IV. 4) When geometrical similarity is held for the dimension of apparatus, Cf depends on Re only. 5) For increment value of resistance coefficient induced by roughness, the relations Cf1≒2Cf2≒4Cf3 hold.

Journal ArticleDOI
TL;DR: In this paper, the dynamic bending stress and moment of an initially curved elastic bar subjected to an axial impact by a rigid mass are analyzed approximately and the results are applied to a rod of rock drill.
Abstract: The dynamic bending stress and moment of an initially curved elastic bar subjected to an axial impact by a rigid mass are analyzed approximately and the results are applied to a rod of rock drill. The analytical results are fairly well in argreement with the experimental results qualitatively as well as quantitatively. It may be said that in the drilling rod the bending stress due to inital deflection is small, but the one due to the eccentric blow is rather large as compared with the longitudinal stress, the main one. These bending stresses increase linearly with the impact velocity and initial deflection or eccentricity of the blow. They are also affected by the mass of the striking body and the slenderness ratio of the rod. The peaks of the stress distribution stand near to the ends.

Journal ArticleDOI
TL;DR: In this article, the authors have carried out the experiment on the transmission of the blow-down energy with an air model simulating the exhaust system of an actual engine, by measuring the kinetic energy of the air ejected from the equivalent nozzle at the pipe end, several factors affecting the energy transmission-pipe length, pipe diameter, area-ratio of the nozzle to the exhaust pipe and exhaust pressure were found out.
Abstract: For the improvement of the performance of a turbocharged Diesel engine with a pulse system, the utilization of the blow-down energy is most essential. The present authors have carried out the experiment on the transmission of the blow-down energy with an air model simulating the exhaust system of an actual engine. By measuring the kinetic energy of the air ejected from the equivalent nozzle at the pipe end, several factors affecting the energy transmission-pipe length, pipe diameter, area-ratio of the nozzle to the exhaust pipe and exhaust pressure-were found out. Further the theoretical calculations were performed by means of the characteristic method. The resulting values agree almost exactly with the experimental ones, when the friction loss in the exhaust pipe is taken into consideration.

Journal ArticleDOI
TL;DR: In this article, the authors have measured the differences in pressure between the inlet and overflow pipes under various operating conditions and have shown that the pressure drop through the cyclone may be represented by the Eq. (4.2).
Abstract: The pressure drop in the hydrocyclone is an important factor along with its performance, since the pump used for the cyclone must be selected according to the pressure drop and also because the amount of necessary energy is dependent upon the pressure drop and the quantity of liquid. The author has measured the differences in pressure between the inlet and the overflow pipes under various operating conditions. The influences of the following factors on the pressure drop were investigated : (1) Feed inlet velocity vi, (2) Diameters of vortex finder Do, underflow nozzle Du and cylindrical portion D, (3) Dimension of inlet nozzle √(bh), (4) Height of cyclone H, (5) Inserted length of vortex finder S, (6) Types of feeding and (7) Pulp density of feed slurries δf. From the results of his experiments, the author has shown that the pressure drop through the cyclone may be represented by the Eq. (4.2).

Journal ArticleDOI
TL;DR: In this paper, the fatigue properties of various metals under supersonic frequency were investigated by means of a magnetostriction transducer through an exponential brass horn, and it was shown that even marks in the most strained part of sample such as might be made by a very light scratch with a knife edge had a considerable effect on the fatigue limit.
Abstract: A testing equipment and measurements are reported of the fatigue of metals under supersonic frequency. This equipment has an advantage over conventional fatigue machines that stress alternations up to 108 reversals can be made within an hour or so. At the resonant condition, metal samples are subjected to alternating stresses above the fatigue limit by means of a magnetostriction transducer through an exponential brass horn. By this method the fatigue properties of various metals were investigated. To avoid temperature rise of the samples, water cooling was necessary. Under insufficient cooling, it was not possible to obtain large motions and high strains, presumably due to the increase of internal damping in the samples. Even marks in the most strained part of sample such as might be made by a very light scratch with a knife edge had a considerable effect on the fatigue limit.

Journal ArticleDOI
TL;DR: In this paper, a mathematical solution on the heat transfer of cooling pipe with constant temperature and laminar flow oil in it is presented, where the partial differential equation of temperature distribution and equations of velocity and pressure gradient are derived, as the viscosity of oil varies only with temperature and the other properties of oil remain unchanged.
Abstract: This paper deals with a mathematical solution on the heat transfer of cooling pipe with constant temperature and laminar flow oil in it. The partial differential equation of temperature distribution and equations of velocity and of pressure gradient are derived, as the viscosity of oil varies only with temperature and the other properties of oil remain unchanged. The author attempts to solve these simultaneous equations. In the process a conception of thermal boundary layer is adopted, and a thermal equation corresponding to the Karman's momentum equation of boundary layer problems is introduced. The calculations of mean temperature θm are compared with the author's experimental results, although sufficient coincidence is diffcult to obtain, due to the difficulty of thermal experiments, but this theory and the experiments are found to agree with each other considerably well. Therefore, the effects of s'and K on the similarity suggested by the author were ascertained.

Journal ArticleDOI
TL;DR: In this article, it has been shown that, in case of free forging, as far as anvil weight ratio is larger than a certain value which is far smaller than that having been said to be the limit, there exists little influence of anvil strength ratio and rigidity of spring on hammer-forging effect.
Abstract: In case of hammer-forging, it has heretofore been said that the forging effect is greatly influenced by anvil weight and rigidity of supporting material (represented in the form of equivalent spring) or, in other words, anvil weight ratio (anvil weight over hammer head weight) and rigidity of spring. However, the writer has found that, in case of free forging, as far as anvil weight ratio is larger than a certain value which is far smaller than that having been said to be the limit, there exists little influence of anvil weight ratio and rigidity of spring on hammer-forging effect. Result of experiments conducted and theoretical explanation therefor are given here.

Journal ArticleDOI
TL;DR: In this article, the authors performed a series of experiments with various Kaplan turbines to study cavitation phenomena against runaway speeds under various conditions and concluded that there are two different types of cavitation phenomenon, the 1st and 2nd types, each with its own aspect of cavitations bubbling and runawy speed.
Abstract: Author performed a series of experiments with various Kaplan turbines to study cavitation phenomena against runaway speeds under various conditions and arrived at the following conclusions : (1) There are two different types of cavitation phenomena, the 1st and the 2nd types, each with its own aspect of cavitation bubbling and runawy speed. (2) In the case of the 1st type, there occurred the identical formation of cavitation bubbles on each of all blades of a runner, while in the 2nd type, the formation of bubbles on every other blades is identical, those on two adjacent blades are not alike. (3) Occurrence of the 1st type or the 2nd type of cavitation bubbles depends upon the value of cavitation co-efficient, number and angle of blades, guide-vane opening, etc., and in many cases the increase in number of blades results in the 2nd type formation of cavitation bubbles.

Journal ArticleDOI
TL;DR: In this paper, a general view of the existing theories on the orthogonal machining in steady state, especially paying attention to the existing limits of the complete solution, is shown, and the existing range of the cutting resistance related to the shear angle φ applying Hill's theorem to the rigid regions.
Abstract: We have shown a general view of the extant theories on the orthogonal machining in steady state, especially paying attention to the existing limits of the complete solution. It is convenient for estimating these limits to investigate the existing range of the cutting resistance P/Tk related to the shear angle φ applying Hill's theorem to the rigid regions. We investigated the generalized case of the Lee and Shaffer's solution with built-up edge and it is proved that the chip should be rigid contrary to Lee and Shaffer. We attempted some experiments using lead specimens and the obtained relations between φ and λ-α coincided with the theory, but the values of P/Tk were scattered and slightly larger than the theoretical range as a whole. It seemed that φ was affected by the initial condition.

Journal ArticleDOI
TL;DR: In this article, the authors considered the replica of the cutting edge roughness and estimate the clarity of the replica with multiple correlation coefficient between edge profile and generated profiles on a work after cutting.
Abstract: As factors of generating roughness in cutting, first we consider the replica of the cutting edge roughness, and estimate clarity of the replica with multiple correlation coefficient between edge profile and generated profiles on a work after cutting. Next we consider the after-effect of the surface roughness of works before cutting, and estimate the degree of after-effect with singular correlation coefficient between the initial and refinished profiles. Both the replica and the after-effect depend on the properties of materials and cutting conditions, but the after-effect can no longer be recognized after the feather cutting. Lastly abnormal roughness, which is generated by disturbance of built-up edge, is estimated with partial correlation coefficient, and auto-generated roughness, which is caused by the non-uniformity of grain size and hardness of materials, is estimated with auto-correlation coefficient. These abnormal and auto-generated roughnesses also depend on both the properties of materials and cutting conditions, but the latter may be found only in the case of fine cutting.