CN1629034A - Energy-saving device for ship sailing - Google Patents

Abstract

This invention comprises the following key points: filling the compressed air into the flow under the boat body water line and above the bilge draft; making the boat body and side greatly decrease the flow intensity and viscosity through the boat moving along so to decrease the total resistance and wave resistance, which naturally decreases the sailing resistance of the boat.

Description

The ship's navigation energy saver

One technical field

The invention belongs to the technical field of " ship energy saving design ".

Two background technologies

1. ship resistance

As everyone knows, boats and ships are subjected to the two opposition to hull of sky G﹠W when navigating by water on the water, and this fluid force opposite with the ship motion direction is referred to as " ship resistance ".

2. the classification of ship resistance

The suffered resistance of boats and ships can be divided into two parts.A part is the total drag (R that bare hull is subjected in hydrostatic _T); Another part is to comprise air resistance (R _A), the augmentation of resistance (R that causes of wave _AW) with the suffered appendage drag of boats and ships etc., these several resistances are referred to as " additional resistance ".Wherein, the total drag (R that in hydrostatic, is subjected to of boats and ships _T) be the main component of ship resistance.About hull total drag (R in the hydrostatic _T) division, please see the following form.

The division of hull total drag in the hydrostatic
			Hull total drag R in the hydrostatic T
Friction drag R F' tangential resistance R F′	Viscous pressure resistance R Pv	Wave making resistance R WPressure drag R P
			Resistance of trailing stream		Wave breaking resistance R WGWaveform resistance R WP
The increase equivalent plank friction drag R of the friction drag that the ship shape curvature causes F		Residuary resistance R R
			Viscosity drag	??R v	Wave making resistance R W
Equivalent plank friction drag R F	Take into account ship shape factor kR F

Illustrate: the friction drag in the table is a hull when motion, is subjected to the effect of the viscous shearing stress of water, and making a concerted effort of on sense of motion, producing; Wave making resistance is ship motion when having prevailed wave, makes the hull surface distribution of pressure change caused resistance; Viscous pressure resistance changes the resistance that forms owing to fluid " astringency " causes hull surface pressure.Fu Rude mainly is divided into the total drag of boats and ships " equivalent plank friction drag " R _F, " viscous pressure resistance " and several aspects such as " wave making resistances ".And equivalent plank friction drag R _FNumerical value can convert according to paying your a moral law of similarity.

3. the expression formula of boats and ships total drag

$R_T=\frac{1}{2}\mathrm{\ρ}{V}^{2}S{C}_T---\left(1\right)$

4. ship resistance has the interrelation of related parameter

Reynolds number: $R_n=\frac{\mathrm{VL}}{v}---\left(2\right)$

The Fu Rude number: $F_n=\frac{V}{\sqrt{\mathrm{gL}}}---\left(3\right)$

Volume is paid you the moral number: $F_{\mathrm{n\Δ}}=\frac{V}{\sqrt{g{\mathrm{\Δ}}^{1/3}}}---\left(4\right)$

More than various in, S is the wetted surface of boats and ships, V is the speed of a ship or plane of boats and ships, v is the kinematic viscosity coefficient of fluid, Δ is a displacement, L is the captain, g is the acceleration due to gravity constant.

1) the expression principle of drag coefficient:

Can directly obtain relation curve between ship model resistance and the speed by the ship model resistance test.Be the quality of resistance performance relatively between the conversion of conveniently carrying out hull resistance and the different ship shape, need be with the relation between resulting resistance of model experiment and the speed, with appropriate being expressed of certain parameter, expression commonly used should be followed following fundamental principle:

A. the parameter that drag coefficient and velocity coefficient comprised should be the given value when design, as captain, displacement, speed etc.;

B. drag coefficient and velocity coefficient should be nondimensional, to avoid the different influences that caused with unit system of absolute measure;

C. the value of drag coefficient should demonstrate peak value and valley, so that accomplish to keep away " peak " just " paddy " as best one can when design.

2) the common method for expressing of drag coefficient:

A. total drag coefficients:

$C_T=\frac{R_T}{\frac{1}{2}\mathrm{\ρS}{V}^2}---\left(5\right)$

B. a drag coefficient and pair your a moral numerical table show method, promptly

$C_T=\frac{R_T}{\frac{1}{2}\mathrm{\ρ}{\mathrm{SV}}^2}$ Or $\frac{R_T}{\frac{1}{2}\mathrm{\ρ}{V}^2{\mathrm{\Δ}}^{2/3}}\≈\frac{V}{\sqrt{\mathrm{gL}}}---\left(6\right)$

This method for expressing is usually used in the resistance conversion, is to make one of method commonly used.

3) conversion of ship model resistance and real ship resistance

The main purpose of ship model resistance test is hydrostatic total drag or the effective power that the resulting ship model resistance of test is converted to real ship.Concrete conversion method has following two kinds:

A. two dimension scaling methods

Be also referred to as and pay you the moral scaling method, promptly resistance is divided into friction drag and two parts of residuary resistance, at the F of ship model and real ship according to the basic assumption of paying your moral _nIn the time of relatively, think that both RRF equate, two friction drags are then tried to achieve by dull and stereotyped coefficient of frictional resistance formula calculating respectively according to the Reynolds number of ship model and real ship.Generally all use the zero dimension drag coefficient to carry out during conversion.For ship model, then have: C _TM=C _FM+ C _RMWherein, C _TMTry to achieve C by model experiment _FMCalculate by the Reynolds number of coefficient of frictional resistance formula,, have: C ship model corresponding with real ship's speed degree when equating (be Fn) according to model experiment _RM=C _RS, the total drag coefficients of real ship: C then _TS=C _FS+ C _RM+ Δ C _F, wherein, Δ C _FBe real ship roughness subsidy.So the total drag that we can write out real ship is:

$R_T=\frac{1}{2}\mathrm{\ρ}{V}^{2}S{C}_{\mathrm{TS}}---\left(7\right)$

B. three dimension scaling methods

Propose in 1954 by the Hughes.This method is divided into 3 parts to ship resistance, it is the wave making resistance that dull and stereotyped friction drag, form resistance (or claiming viscous pressure resistance) and free surface cause, and think that the ratio of form drag coefficient and dull and stereotyped coefficient of frictional resistance is a constant, it does not become with Reynolds number, only depend on hull shape, that is: C _TM=(1+k) C _FM+ C _RMKC wherein _FMBe form drag coefficient, promptly " form drag coefficient " in " RRF " that " two dimension methods " comprised incorporates into among the coefficient of frictional resistance that is subjected to Reynolds number effect, and constitutes a fixed fraction of coefficient of frictional resistance.At this moment, the total drag coefficients of real ship should be:

C _TS＝(1+k)C _FS+C _RM+C _A+C _AA??????????????????(8)

Resistance converts and carries out according to following formula in " single slurry ship performance prediction method " of the 15th ITTC proposition in 1978, and is defined as:

$C_A=\left\{105\right(\frac{K_S}{L_{\mathrm{WL}}}{)}^{1/3}-0.64]\×{10}^{-3};$

$C_{\mathrm{AA}}=0.001\left(\frac{A_{\mathrm{TV}}}{S}\right).$

K in the formula _sIt is the average fluctuation margin of hull rough surface in the 50mm length.

5. additional resistance

As known to, boats and ships are in when navigation, except that hull was subjected to friction drag, wave making resistance and viscous pressure resistance, the various attached body of boats and ships and the perforate on the hull also can be subjected to the effect of resistance; Meanwhile, hull and superstructure part that the boats and ships water surface is above also will be subjected to air resistance; Moreover, owing to the aquatic organism of the paint flake on the ship hull plate, corrosion and adhesion causes fouling resistance; In addition, marine stormy waves also can make resistance in the resistance ratios hydrostatic of boats and ships that to a certain degree increase is arranged: the resistance of all these additive incrementations, we are referred to as " additional resistance " by system.

Three summary of the invention

In view of the factor that causes the boats and ships additional resistance complicated, so wouldn't give consideration here.After getting rid of additional resistance, can find by relational expression (7): the total drag (R of boats and ships _T) just the density (ρ) with fluid be inversely proportional to.Also have, know the wave making resistance (R of fluid by Hydrodynamics Theory _W) and viscous pressure resistance (R _Pv) not only relevant with density, but also relevant with its viscosity (ν), that is: viscosity is big more, its viscous pressure resistance and wave making resistance are also just big more.Edify us therefrom:, also just can change the suffered running resistance of boats and ships to a great extent if can in the process of ship's navigation, reduce the density and the viscosity of fluid at any time.Not hard to imagine, in fluid, charge compressed-air actuated way, can reduce the density and the viscosity of fluid to a certain extent.For this reason, the present invention intends adopting and charges compressed-air actuated way to the relevant position of stem, reaches the running resistance that reduces boats and ships, improves its shipping economy.

Four concrete schemes

Concrete scheme of the present invention is: in conjunction with the shape of real ship ball dagger, make " porous pressurized air mixing jetting cover " (referring to a Fig. 3) who is made up of stainless steel tube.Before launching, this " jet cover " is fixed on the corresponding site of stem, with it ball dagger is covered (referring to Fig. 2).The shape of this air mixed injecting cover should become to leave about 1000～4000 millimeters space lengths that do not wait of ball dagger in conjunction with the shaped design of stem, and its concrete size can be determined according to bow shape and by tank experiment.At the fumarole of the disposed inboard some of all gas ejector pipes of jet cover, the outgassing direction of these fumaroles should be as far as possible and the working direction opposite (referring to Fig. 4) of boats and ships.Fumarole diameter and quantity should determine according to calculating with tank experiment, should and prevent that forming " cavitation pitting impact " is basic premise with the running resistance of effective reduction boats and ships.And, two air compressor unit and two air bottles (standby each other) are installed in appropriate location in the stem cabin, several groups of pipelines all are set between each air bottle and jet cover, and on every group of pipeline, establish two electromagnetic valves with cut-off non-return function, so that control the mode of operation of every group of jet cover according to the drinking water situation of boats and ships.The control system of this device is arranged on operator platform, carries out distance control (referring to Fig. 1).

Five description of drawings

Fig. 1. ship's navigation energy saving apparatus block diagram

Fig. 2. ship's navigation energy saver scheme of installation

Fig. 3. air mixed injecting cover contour structures scheme drawing

Fig. 4. the partial enlarged drawing of air mixed injecting cover position A

Six specific embodiment

Before implementing this programme, must carry out tank experiment.Have only by tank experiment, could determine the oad of this energy saver, the diameter of gas ejector pipe, quantity and the size in aperture, the power of air compressor and the capacity of air bottle etc. of fumarole.After having determined above-mentioned parameter, just can design corresponding energy saver, and before launching, it is fixed on the position of stem in conjunction with the shape of real ship stem.

Claims (1)

1. Technical characterictic

   Technical characterictic of the present invention is: charge pressurized air in the fluid more than the waterline in stem the place ahead absorbs water with hull bottom down, cause the density and the viscosity of stem and topside part correlation fluid to descend, thereby reduce these fluids to boats and ships formed " total drag " and " wave making resistance ", and then reach fuel saving, increase the speed of a ship or plane, improve the basic goal of boats and ships shipping economy.

   The scope of asking for protection

   1. by under the waterline of stem the place ahead, in the fluid more than the hull bottom drinking water, charging pressurized air, reduce the density and the viscosity of these fluids, thereby reach any device that reduces ship resistance.

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