水下无人系统学报

Influences of Surface Characteristics of Underwater Vehicle on Its Hydrodynamic Properties

WANG Zai-duo, WANG Wei, ZHANG Xiao-shi

2015, 23(5): 321-325. doi: 10.11993/j.issn.1673-1948.2015.05.001

[Abstract](1463) [PDF 675KB](437)

Abstract:
To optimize the headform design of an underwater vehicle, water tunnel experiment was conducted to analyze the influences of different surface characteristics of the headform on hydrodynamic properties of the vehicle. The headform includes grooved surface, concave surface and smooth surface. The natural cavity shape, the periodical fluctuation of the cavity and the drag coefficient for different head surface were obtained. The results show that: 1) for same cavitation number, the vehicle with smooth head surface has higher cavitation resistance, but the grooved and concave head surfaces are easier to generate cavitation with complete and transparent partial cavities; 2) the smooth head surface produces unsteady and non-observable cavities, while the grooved and concave head surfaces produce steady cavities with periodic fluctuation; and 3) in a certain speed range, the unsmooth head surfaces (i.e. grooved head surface and concave head surface) can gain better drag reduction property compared with the smooth head surface, and at a speed of 12.8 m/s they can obtain the best drag reduction amount of 5% and 8%, respectively.

Optimization Method of Overall Performance Parameters of Torpedo via Simulation Based on Neural Network Response Surface

FAN Ruo-nan, ZENG Jing, REN Qing-sheng, LI Bin

2015, 23(5): 326-331. doi: 10.11993/j.issn.1673-1948.2015.05.002

[Abstract](1162) [PDF 332KB](422)

Abstract:
Underwater acoustic homing simulation can exhibit operational effectiveness of a torpedo in a real environment, however a large number of sample data is needed in the simulation for the overall performance parameters optimization of the torpedo, thus optimization time becomes the bottleneck. Based on the quick neural network response surface method(NN-RSM), this paper uses the space mapping method to reduce the cost of optimization calculation and directly get the optimal solution to the underwater acoustic homing system. Subsequently, the overall performance indices of a torpedo, such as homing range and damage radius, are optimized. Optimization results show that effective optimization of the original problem is achieved with computation time less than 1/20 that of the general optimization methods. The present method can be applied to optimization of other complicated system with multiple parameters and multiple objectives.

Compensation Scheme of Amplitude-Phase Error for Multi-Channel Sonar Receiver

CHEN Fa, LI Yong-sheng, LÜ Lin-xia

2015, 23(5): 332-337. doi: 10.11993/j.issn.1673-1948.2015.05.003

[Abstract](849) [PDF 607KB](442)

Abstract:
The inconsistency of pretreatment circuit components of a multi-channel sonar receiver may bring fixed deviation of amplitude-phase consistency to the signal processing at backend. Inspired by the amplitude-phase equilibrium of a multi-channel radar, the authors analyze the measurement methods of signal parameters, and present an error compensation scheme based on fast Fourier transform(FFT). In this scheme, FFT is employed to measure the fixed deviation and the frequency of input acoustic signal, and the compensation is hence achieved by complex multiplication. The scheme is an additional field programmable gate array(FPGA) module without any influence on the original structure of a receiver. Simulation shows that the amplitude error of output compensated signal is less than 1%, the phase error is less than 1°, and the additional time delay of correction is very small.

Optimization of Searching Beam for Acoustic Homing Torpedo

LEI Ming, ZHANG Jing-yuan, RAO Zhe

2015, 23(5): 338-342. doi: 10.11993/j.issn.1673-1948.2015.05.004

[Abstract](1186) [PDF 302KB](463)

Abstract:
To understand the influence of acoustic homing torpedo searching beam on searching efficiency, the relation between torpedo searching beam width and homing range is derived based on the active sonar equation and the solid angle formula. According to the characteristics of snake trajectory, a model of torpedo searching area is built. The influences of various factors on torpedo searching efficiency are quantitatively analyzed, and the optimized beam width range from 15°to 25°is determined. This study may provide a reference for design of sonar array and operational application of an acoustic homing torpedo.

Design and Implementation of Micro Underwater Acoustic Signal Acquisition and Storage System

SHANG Fan, HAO Dong-xu

2015, 23(5): 343-347. doi: 10.11993/j.issn.1673-1948.2015.05.005

[Abstract](822) [PDF 450KB](382)

Abstract:
Based on the advanced RISC machines(ARM) microcontroller and TF card, a micro underwater acoustic signal acquisition and storage system was designed to solve the problem that the underwater acoustic information in test cannot be collected and stored with high fidelity for a long time. High integration analog and digital chips were combined effectively in the hardware design to gain the advantages of small size(3×8 cm), low power consumption, flexible parameter setting, and convenient embedding into small-size acoustic equipment. The software was designed by using direct memory access(DMA) plus ping-pang buffer acquisition mode to ensure data acquisition and storage of the micro controller without interruption and missing, and hence to support the system working stably and reliably for a long time. This system has been successfully applied in an underwater noise acquisition experiment.

Experimental Investigation on Heat Transfer Characteristic of Shell Condenser

HAN Yong-jun, BAI Chao, YANG Cheng-shi, PENG Bo, GUO Zhao-yuan, LU Jun, MA Wei-feng

2015, 23(5): 348-352. doi: 10.11993/j.issn.1673-1948.2015.05.006

[Abstract](734) [PDF 474KB](374)

Abstract:
To reveal the heat transfer characteristic in the shell condenser of a closed-loop thermal propulsion system, experimental research was conducted on a shell condenser with multi-groups helical rectangular channels. The effects of flow rate and temperature of inlet steam on the heat transfer performance of the condenser were analyzed. The results indicate that the multi-group helical rectangular channels can enhance heat transfer performance, and the heat transfer performance improves as the Reynolds number increases. In addition, the total average heat transfer amount, the heat flow density, and the outlet temperature of condensed water increase as the flow rate and temperature of the inlet steam rise. On the other hand, the total heat transfer coefficient and the steam-side heat transfer coefficient decrease as the inlet steam temperature rises, while they increase as the flow rate of inlet steam increases. However, the outlet temperature of the condensed water changes slightly when the inlet steam flow rate increases. Consequently, a criterion formula of heat transfer is derived based on the experimental data to provide a basis for the design of shell condensers.

A Design Approach of Micro Partial Admission Impusle Turbine

JIANG Bin, LUO Kai, GAO Ai-jun, FENG Qi-xi, YI Jin-bao

2015, 23(5): 353-358. doi: 10.11993/j.issn.1673-1948.2015.05.007

[Abstract](1205) [PDF 529KB](500)

Abstract:
For improving the current design method of micro partial admission impulse turbine, a design approach of the micro partial admission turbine is proposed by analyzing the micro turbine’s loss characteristics. In addition, the rationality of the design approach is examined numerically, the variable working conditions are investigated, and the prototype is designed. The results indicate that the error of the designed turbine’s inner efficiency between simulation results and the design parameters is less than 3%; the blade cascade and the shroud can suppress the flow separation at the nozzle’s outlet under a big ambient pressure; the impact loss on the blade cascade increases under off-designed rotational speeds; the turbine can gain larger output power by changing nozzle number. The design method can provide a reference for the optimization design and test of the micro turbine.

Loss and Temperature Analysis of a Coreless Disc Permanent Magnet Synchronous Motor

WANG Jun-jie, MA En-lin

2015, 23(5): 359-366. doi: 10.11993/j.issn.1673-1948.2015.05.008

[Abstract](1008) [PDF 2017KB](566)

Abstract:
Loss and temperature field analysis is important to ensure safe operation of the missile coreless disc permanent magnet synchronous motor (PMSM). According to the performance of the missile actuator, this paper designs a basic structure of coreless disc PMSM, and analyzes the Joule loss, iron loss and eddy current loss of the motor with load by using the JMAG- Designer. The motor temperature field is analyzed by the three-dimensional finite element analysis. The results show that under rated power, the temperature rise of this motor meets the requirements of performance of the missile actuator.

Numerical Simulation of Combined Liner Formation in Water

FU Lei, WANG Wei-li, LI Yong-sheng, JIANG Ying-zi

2015, 23(5): 367-373. doi: 10.11993/j.issn.1673-1948.2015.05.009

[Abstract](991) [PDF 2007KB](416)

Abstract:
To enhance damage effect of torpedo warhead on large warship, a combined liner with annular-spherical segment/large cone angle structure is taken as the front charging chamber of the torpedo tandem warhead. The combined liner is composed of an annular liner around and a spherical segment liner or a large cone angle liner in the center. The formation mechanism of the combined liner in water is analyzed by the software LS-DYNA. The influences of the cone and curvature radius on the formation of the central liner in water are investigated in two priming modes. Simulation results show that: the annular liner forms annular jet in water to cut first layer of target shell; the change of central liner structure has little influence on jet formation of the annular liner; the long and the thin rod-liked jet formed by the central large cone liner has a high head velocity, while the rod-liked penetrator formed by the central spherical segment liner has a short and thick shape and relatively small velocity gradient.

Feasibility Analysis of Underwater Submunition Group Defense Against Torpedo

JIANG Wen-lu, MA Feng, WANG Shu-shan

2015, 23(5): 374-378. doi: 10.11993/j.issn.1673-1948.2015.05.010

[Abstract](1076) [PDF 388KB](376)

Abstract:
Traditional anti-torpedo weapons are difficult to achieve expected interception effect due to the errors of sonar detection and location. To compensate these errors, a method for deploying submunition group is put forward to intercept a torpedo by the cargo projectiles usually used in the ground guns. In this method, submunition group is deployed in a certain area with certain depth on predicted incoming torpedo trajectory. The submunition distribution is determined by analyzing the damage power of a warhead, and the damage probability is simulated by the Monte-Carlo method. The effects of the factors, such as shooting accuracy, shooting distance, shooting location and submunition number, on the damage probability are analyzed. The assumptions analysis indicates that the application of submunition group to anti-torpedo operation can effectively enhance the damage effectiveness, and this method is feasible in principle.

Influence of Vessel Evasion on the Dispersion Law of Torpedo Trajectory in Tracking Section

LU Meng-wei, MA Feng, WEI Ji-feng, WANG Shu-shan

2015, 23(5): 379-383. doi: 10.11993/j.issn.1673-1948.2015.05.011

[Abstract](891) [PDF 363KB](457)

Abstract:
Evasive maneuver is the foundation and prerequisite of a vessel defense against a torpedo. By analyzing the battlefield situation in homing tracking section of an acoustic homing torpedo, this paper establishes a mathematical model of a vessel defending against an acoustic homing torpedo, and selects the evasion strategies for a vessel rapidly running away from the large board angle incoming torpedo by placing in the stern direction, then analyzes the dispersion characteristics of torpedo attack trajectory in the influence of vessel evasion. Moreover, this paper provides a decision-making basis according to different anti-torpedo hard killing weapons. This study may provide a reference for improving the survival ability of a vessel and for decision making in anti-torpedo operation.

Conceptual Study on Tactics of Torpedo in Underwater Network Centric Warfare

NIE Wei-dong, WANG Lan, MA Ling

2015, 23(5): 384-387. doi: 10.11993/j.issn.1673-1948.2015.05.012

[Abstract](862) [PDF 1188KB](735)

Abstract:
Information- and network-based torpedo is the critical weapon in underwater network centric warfare(UNCW). It is a type of intelligent weapon for future war. The principal difference between such torpedo and the traditional one lies in the way of obtaining and dealing with information. In this paper, various patterns of forming battlefield network are discussed, and several operational modes for the information- and network-based torpedo are summarized to provide tactical and technical references for UNCW.

Numerical Simulation of Torpedo Receiving Tube of False Sea Test Facility Based on CFD

WANG Xian-ming, DUAN Hao, WANG Yun

2015, 23(5): 388-393. doi: 10.11993/j.issn.1673-1948.2015.05.013

[Abstract](739) [PDF 1081KB](374)

Abstract:
Receiving tube is an important component of false sea test facility. Its main function is to receive the launched torpedo coming along guide pipe, and to make the torpedo slow down and stop in it. In this study, the motion processes of a torpedo into the receiving tube are simulated with a series of parameters by making use of the shear stress transmission(SST) model and dynamic mesh in the commercial software CFD. The parameters include the receiving tube′s inside radii and length, the torpedo speed, etc. The effects of these parameters on the torpedo motion process are acquired. Simulations show that the process of a torpedo entering into the receiving tube has obvious nonlinear characteristics due to the effect of water. The simulation results may provide verification and support for design of receiving tube.

Simulation on Interior Ballistics of Push-Pull Cylinder Type Torpedo Launcher

GUO Yu, LI Zong-ji, REN Lei, LIAN Yong-qing

2015, 23(5): 394-400. doi: 10.11993/j.issn.1673-1948.2015.05.015

[Abstract](1236) [PDF 458KB](358)

Abstract:
To make an underwater unmanned vehicle(UUV), which is small in volume and light in weight, has the ability of launching a torpedo, a scheme of push-pull cylinder type torpedo launcher for an UUV is proposed on the basis of traditional torpedo launcher. And a mathematic model of interior ballistics is built for the launcher to simulate the influences of main structural parameters on the interior ballistics of the push-pull cylinder type torpedo launcher. Simulation shows that this scheme meets the technical requirements for the UUV launching a torpedo. This study may provide a reference for further research of this topic.

2015 Vol. 23, No. 5

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