• Title, Summary, Keyword: Disk type

Search Result 918, Processing Time 0.044 seconds

Dynamic modeling and three-dimensional motion simulation of a disk type underwater glider

  • Yu, Pengyao;Wang, Tianlin;Zhou, Han;Shen, Cong
    • International Journal of Naval Architecture and Ocean Engineering
    • /
    • v.10 no.3
    • /
    • pp.318-328
    • /
    • 2018
  • Disk type underwater gliders are a new type of underwater gliders and they could glide in various directions by adjusting the internal structures, making a turnaround like conventional gliders unnecessary. This characteristic of disk type underwater gliders makes them have great potential application in virtual mooring. Considering dynamic models of conventional underwater gliders could not adequately satisfy the motion characteristic of disk type underwater gliders, a nonlinear dynamic model for the motion simulation of disk type underwater glider is developed in this paper. In the model, the effect of internal masses movement is taken into consideration and a viscous hydrodynamic calculation method satisfying the motion characteristic of disk type underwater gliders is proposed. Through simulating typical motions of a disk type underwater glider, the feasibility of the dynamic model is validated and the disk type underwater glider shows good maneuverability.

An Experimental Study on the Effect of Performance for Channel of Disk-type Drag Pump Rotors (원판형 드래그펌프 회전자의 채널이 성능에 미치는 영향에 관한 실험적 연구)

  • Kwon, Myoung-Keun;Lee, Soo-Young;Hwang, Young-Kyu
    • Proceedings of the KSME Conference
    • /
    • /
    • pp.1703-1708
    • /
    • 2004
  • In this study, we are investigated experimentally the pumping characteristics about the pumping channel shapes of disk-type drag pump (DTDP). We are experimented the pumping performance about the rotors which have channel or do not exist. The channel disk-type rotor has spiral channels both upper and lower part, and stator is planar. The planar disk-type rotor hasn't channel and stator has spiral channels both upper and lower part. The flow-meter method is adopted to calculate the pumping speed. Compression ratio and pumping speeds for the nitrogen gas are measured under the inlet pressure range of 0.001 ${\sim}$ 4 Torr. The maximum of compression ratio was about 3300 for three-stage DTDP (channel disk-type rotor), 1000 for four-stage (planar disk-type rotor) and two-stage DTDP (channel disk-type rotor) at zero throughput. The ultimate pressure was $1.6{\times}10^{-6}$ Torr for three-stage DTDP (channel disk-type rotor), $2.5{\times}10^{-6}$ Torr for four-stage DTDP (planar disk-type rotor).

  • PDF

Atomization Chracteristics of Spinning Disk for Spray Dry (분무건조를 위한 회전원판의 미립화 특성에 관한 연구)

  • Oh, Jae-Geon;Park, Ki-Ho;Park, Jun-Taek;Lim, Sang-Gun
    • Journal of the Korean Society of Industry Convergence
    • /
    • v.3 no.4
    • /
    • pp.353-360
    • /
    • 2000
  • The purpose of this research is to find the fundamental data for the design and optimum operation condition for the disk atomization comparing the atomization characteristics of the modified straight vane type disk atomizer and the cup type atomizer widely used in the field of spray dry. First, the experimental comparison of the characteristics of $Na_2SO_4$ atomization has been carried out using the cup type disk atomizer and the three kinds of vane type atomization designed specially for the experiment. After the comparison of the experimental data of the $Na_2SO_4$ and raw milk have been conducted using vane type atomizer.

  • PDF

Posterior Disk Displacement in the Temporomandibular Joint: A Report of Two Cases

  • Kim, Jihoon;Kim, Moon-Jong;Kho, Hong-Seop
    • Journal of Oral Medicine and Pain
    • /
    • v.41 no.3
    • /
    • pp.137-143
    • /
    • 2016
  • Posterior disk displacement (PDD) of the temporomandibular joint (TMJ) is a rare condition and most descriptions of TMJ PDD are about the adhesion of superior TMJ in which the position of disk is relatively posterior to anteriorly translated condyle in open mouth position. However, there have been reports about truly posteriorly positioned disk to the condyle in closed mouth position. This type of PDD has been classified into three subtypes-thin flat disk type, grossly posterior displaced disk type, and perforated disk type. Here, we report two rare cases of TMJ PDD, one with thin flat disk and one with perforated disk. Its possible etiology, pathogenetic mechanisms, related signs and symptoms, differential diagnoses, and treatments were reviewed and discussed.

A Study on Friction Coefficient of Disk Brake Lining for Rolling Stock According to Disk Type (디스크 타입에 따른 철도차량용 디스크 브레이크 라이닝의 마찰계수 특성에 관한 연구)

  • Kwon Sung-Tae;Kim Won-Kyung;Kim Jeong-Guk;Yoon Sung-Hwan
    • Proceedings of the KSR Conference
    • /
    • /
    • pp.472-476
    • /
    • 2004
  • In this study, we investigate the change characteristic of friction coefficient of disk brake lining for rolling stock according to disk type, The actual brake tests were carried out under constant brake force and operating sequence by using dynamo-tester. Test results showed that instant friction coefficient was higher in the case of devided disk type rather than single body disk type, Also, averge friction coefficient was appeared similer to the above result. It is thought that ,in the case of devided disk type, friction resistance was increased due to the gap between both side of half disk.

  • PDF

A Study for the Cooling Performance of a Brake with Heat Pipes (히트 파이프를 장착한 디스크브레이크의 냉각 성능에 관한 연구)

  • Kim, Moo-Geun;Ko, Sung-Kyu;Lee, Moon-Wan
    • Journal of the Korean Society of Marine Engineering
    • /
    • v.32 no.4
    • /
    • pp.563-569
    • /
    • 2008
  • During braking operation, the surfaces of disk have severe contact conditions and high frictional heat would be generated between disk and pad surfaces. The heat makes high temperature gradient on disk surfaces and results in thermal deformation. To enhance the frictional heat dissipation, heat pipes are embedded in the ventilated type disk along the radial direction. The temperatures of the inner vent type disk and the brake disk with heat pipes are compared at the same operating conditions. By comparison a brake disk with heat pipes has higher cooling performance than the inner vent type disk.

Magnetic resonance imaging signal intensity of temporomandibular joint disk and posterior attachment in patients with internal derangement (측두하악관절 내장 환자의 관절원판과 관절원판 후조직의 자기공명영상 신호강도)

  • Jeong Yeon-Hwa;Cho Bong-Hae
    • Imaging Science in Dentistry
    • /
    • v.31 no.2
    • /
    • pp.93-99
    • /
    • 2001
  • Purpose: To analyze the possible association between magnetic resonance imaging signal intensity of temporomandibular joint disk and posterior attachment, and the type and extent of disk displacement, disk configuration, effusion and clinical signs in patients with internal derangement. Materials and Methods: Magnetic resonance images of the 132 temporomandibular joints of 66 patients with temporomandibular joint displacement were analyzed. The clinical findings were obtained by retrospective review of the patients' records. The type and extent of disk displacement, disk configuration and effusion were evaluated on the proton density MR images. The signal intensity from the anterior band, posterior band and posterior attachment were measured on MR images. The associations between the type and extent of disk displacement, disk configuration, effusion and clinical signs and the MR signal intensity of disk and posterior attachment were statistically analyzed by student's t-test. Results: Of 132 joints, 87 (65.9%) showed anterior disk displacement with reduction (ADR) and 45 (34.1%) showed anterior disk displacement without reduction (ADnR). The signals from posterior attachments were lower in joints with ADnR than those of ADR (p<0.05). The results showed statistically significant (p<0.05) association between the type and extent of disk displacement and disk configuration, and decreased signal intensity of posterior attachment. There were no statistical associations between pain, noise and limited mouth opening, and signal intensity of disk and posterior attachment. Conclusions: The average signal from posterior attachment was lower in joints with ADnR than that of ADR. The type and extent of disk displacement and disk configuration appeared to be correlated with the signal intensity from posterior attachment.

  • PDF

A Driver Design of Disk Type LOA for Decrease Displacement Pulsatory Motion (변위 맥동 저감을 위한 Disk Type LOA의 구동드라이버 설계)

  • Jang Seok-Myeong;Choi Byung-Heon;Kwon Jeong-Ki;Cho Han-Wook;Jeong Sang-Sub
    • Proceedings of the KIEE Conference
    • /
    • /
    • pp.1094-1096
    • /
    • 2004
  • This paper deals with driver design for displacement pulsation reduction of disk type LOA. Manufactured disk type LOA consists of iron cored disk as a mover and coil wrapped stator which is located at two sides with respect to mover origin.

  • PDF

Braking Characteristics of Friction Disk made of Carbon Paper for Wet-type Multiple Disk Brakes of Crane Turning Decelerator (크레인 선회감속기의 습식 다판 브레이크를 위한 카본 페이퍼 마찰 디스크의 제동 특성)

  • Cho, Yonsang;Bae, Myongho
    • Tribology and Lubricants
    • /
    • v.28 no.3
    • /
    • pp.112-116
    • /
    • 2012
  • wet-type multiple disk brakes are very important parts of turning decelerator for deck crane, because they are advanced in durability and braking power, and can be designed compactly. Thus, we designed and made wet-type multiple disk brakes of turning decelerator for deck crane to be localization of these imported all. In this study, wet multiple disk brakes were made a comparative test with the 2 types materials of friction disk by the SAE No.2 dynamometer. The friction characteristics were measured and analyzed to decide a suitable material as wear depth of friction disk and dynamic and static friction coefficient.

Finite Element Analysis of Step-down Piezoelectric Transformer with Various Shape (형태의 변화에 따른 강압용 압전변압기의 유한요소해석)

  • Chong, Hyon-Ho;Park, Tae-Gone;Kwon, Oh-Young
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • /
    • pp.697-700
    • /
    • 2003
  • This paper presents design and analysis of step-down piezoelectric transformer for application to AC-adapters. These transformers are consist of rectangular type and disk type multilayered piezoelectric ceramic plate. This piezoelectric transformer operated in third thickness resonance vibration mode. Finite element methode(FEM) was used for analysing transformer. Vibration mode and electric field of piezoelectric transformer were simulated at resonance frequency. As results, rectangular type transformer's output voltage was higher than the disk type. But disk type transformer's current was lagger than rectangular type. These results are assumed that disk type transformer's mixed vibration mode influence transformer's output characteristics. From these results, we expect that disk type piezoelectric transformer is more adoptable than rectangular plate type piezoelectric transformer for AC adapters.

  • PDF