CN102849178A - Method for acquiring container ship resistance - Google Patents

Abstract

The invention discloses a method for acquiring container ship resistance. The method includes: firstly, designing or measuring principal dimensions and related parameters of a ship; secondly, acquiring draft total resistance or ballast draft total resistance by the method according to the ship type and the draft/ballast draft statues. The optimized ship wet-surface area calculation method and the optimized wave-making resistance and frictional resistance calculation method are adopted respectively. In addition, by comparing the method with actual ship model test, a novel total-resistance correction method is determined, and a resistance calculation method high in calculating precision and widely applicable is provided for shipping engineers in the initial design phase of container ships, so that ship design efficiency is improved greatly. The method for acquiring container ship resistance is applicable to the ship design phase and the ship resistance actual-detection phase and has the advantages of convenience, high efficiency and accuracy in results.

Description

A kind of method of obtaining box ship boats and ships resistance

Technical field

The present invention relates to the acquisition methods of ship resistance, more particularly, relate to when determining that the correlation parameters such as dimension of ship obtain the actual maritime navigation of boats and ships because the drag size of the effect generation of water.

Background technology

In the manufacture process of boats and ships, need to know ship resistance at design phase, in order to instruct the follow-up parameter designing of boats and ships.As, in the resistance acquisition process of prior art, finish or build in ship design and can determine following parameter after finishing: block coefficient Cb, coefficient of waterplane Cwp, midship section coefficient Cm.These coefficients are relevant with the structure of boats and ships.

The traditional ship resistance evaluation method that uses when Preliminary Ship Design (such as Series 60 series, Holtrop method etc.) is usually more old, narrow application range (as to Cb, the restriction of Fn), and precision is lower.Need the resistance acquisition methods that precision is high, applied widely in the Preliminary Ship Design stage.

After this external launching, the resistance situation that also needs actual detection boats and ships to be subject to, this needs a large amount of check implements, and the labor intensive material resources are finished detection.

Summary of the invention

The invention provides a kind of method of obtaining ship resistance by dimensional parameters definite or the measurement boats and ships, its purpose is intended to obtain the resistance result in order in the ship design stage the further improvement design of boats and ships is done to instruct by simple, fast method, perhaps provides a kind of convenient, resistance detection method cheaply in measuring phases.

In order to achieve the above object, the invention provides a kind of method of obtaining box ship boats and ships resistance, comprise the steps:

S1, by design or measure principal dimensions and the following parameter obtain boats and ships:

Length between perpendiculars Lbp, unit: rice;

Waterline overall length Los, unit: rice;

Length on water line Lwl, unit: rice;

Molded breadth B, unit: rice;

Drinking water T, unit: rice;

Aft draft Ta, unit: rice;

Draught forward Tf, unit: rice;

Diameter of propeller Dp, unit: rice;

Obtain following parameter by design or calculating:

Block coefficient Cb;

Coefficient of waterplane Cwp;

Midship section coefficient Cm;

Speed of a ship or plane V, unit: meter per second;

Attached body-moisture meter area A ppendix_Area, unit: sq m;

Ball bow area of section Abt, unit: sq m;

S2, according to following formula Ship ' wetted surface area S, unit: sq m;

$S=\mathrm{Lwl}(2T+B){C_m}^{0.5}(0.3696C_{\mathrm{wp}}+0.453+0.4425C_b-0.2862C_m-0.003467\frac{B}{T})$

$+2.38\frac{\mathrm{Abt}}{C_b}+\mathrm{Appendix}\_\mathrm{Area}$

S3, calculating friction drag, wave making resistance comprise the steps;

1) calculate Froude number Fn:

At first, calculate L according to the size of Los _Fn

L _fn＝L _os L _os＜1

L _fn＝L+2/3(L _os-L) 1≤L _os/L＜1.1

L _Fn=1.0667L 1≤L _Os/ L＜1.1; Wherein, L=Lbp;

Then calculate F _n=V/ (L _FnG) ^1/2, wherein, g is acceleration due to gravity, unit: m/s ²

2) friction drag is calculated as follows:

R _n＝VL _os/γ

C _f＝0.075/(log ₁₀R _n-2) ²

R _f＝0.5C _fSρV ²

Wherein: water movement coefficient of viscosity γ, unit: m ²/ s;

The density p of water, unit: kg/m ³

S4, calculating residuary resistance:

R _Rmean＝0.5C _R(0.1BT)ρV ²

R _Rmin＝0.5C _Rmin(0.1BT)ρV ²

C _R＝C _R1C _R2K _L(T/B) ^b1(B/L) ^b2(L _os/L _wl) ^b3(L _wl/L) ^b4

(1+(T _A-T _F)/L) ^b5(D _P/T _A) ^b6

C _Rmin＝C _R1(T/B) ^b1(B/L) ^b2(L _os/L _wl) ^b3(L _wl/L) ^b4

(1+(T _A-T _F)/L) ^b5(D _P/T _A) ^b6

Wherein:

$C_{R1}=c_{11}+c_{12}{F}_n+c_{13}{F}_n^2+C_B(c_{21}+c_{22}{F}_n+c_{23}{F}_n^2)$

$+C_B^2(c_{31}+c_{32}{F}_n+c_{33}{F}_n^2)$

C _R2＝max(1.0，(F _n/F _n1) ^f1)

$F_{n1}=d_1+d_2{C}_B+d_3{C}_B^3$

K _L＝e ₁L ^e2

In addition, the parameter in the above-mentioned formula is according to ship type and drinking water/ballast draft state, and ginseng is determined according to following table:

	Designed draft CR	Designed draft CRmin	Ballast draft CR
				b1	-0.3382	-0.3382	-0.7139
b2	0.8086	0.8086	0.2258
				b3	-6.0258	-6.0258	-1.1606
b4	-3.5632	-3.5632	0.4534
				b5	9.4405	0	11.222
b6	0.0146	0	0.4524
				c11	-0.5742	-0.91424	-1.5016
c12	13.3893	13.3893	12.9578
				c13	90.5960	90.596	-36.7985
c21	4.6614	4.6614	5.5553
				c22	-39.721	-39.721	-45.8815
c23	-351.483	-351.483	121.820
				c31	-1.14215	-1.14215	-4.3357
c32	-12.3296	-12.3296	36.0782
				c33	459.254	459.254	-85.3741
d1	0.854	0	0.032
				d2	-1.228	0	0.803
d3	0.497	0	-0.739
				e1	2.1701	0	1.9994
e2	-0.1602	0	-0.1446

S5, according to ship type described in the step S4 and drinking water/ballast draft state, utilize the total drag of the corresponding calculating of following formula drinking water state or ballast draft state:

Drinking water state total drag R _t=0.5 (R _Rmin+ 1.204R _Rmean)+R _f, unit: N;

Ballast draft state total drag R _t=1194R _Rmean+ R _f, unit: N.

The present invention is the requirement of satisfying box ship boats and ships conceptual design, the design phase resistance of offering calculates, and this method has adopted respectively boats and ships wetted surface area method of calculating and wave making resistance and the friction drag method of calculating optimized.Simultaneously by with real ship model Experimental Comparison, determined a kind of modification method of new total drag.So that marine engineers have a drag computation method that design accuracy is high, applied widely in the box ship boats and ships concept phase.Can improve the efficient of ship resistance forecast, save design time, the save design cost.The acquisition methods of box ship boats and ships resistance of the present invention, the resistance when can be used for the box ship preliminary design is estimated.Be applicable to designed draft/ballast draft state.Total drag result and model test result that this method is obtained can be controlled in about 3-5%, have the high characteristics of design accuracy, and be applied widely, efficient that can larger raising Preliminary Ship Design.

Description of drawings

Fig. 1 utilizes the inventive method to obtain the diagram of circuit of ship resistance;

Fig. 2 is the positional representation schematic diagram of boats and ships part principal dimensions.

The specific embodiment

Diagram of circuit as shown in Figure 1, the process that the present invention obtains ship resistance at first needs by design or measures principal dimensions and the correlation parameter that obtains boats and ships, comprises specifically following process.

Step 1, preliminary principal dimensions and other correlation parameter of determining the design boats and ships, as follows;

Lbp: length between perpendiculars (m)

Los: (the waterline overall length is that boats and ships calculate under waterline rearmost end and the waterline distance foremost to waterline overall length (m), as shown in Figure 2)

Lwl: length on water line (m)

B: molded breadth (m)

T: drinking water (m)

Ta: aft draft (m)

Tf: draught forward (m)

Dp: diameter of propeller (m)

Obtain following parameter by design or calculating:

Cb: block coefficient

Cwp: coefficient of waterplane

Cm: midship section coefficient

V: the speed of a ship or plane (m/s)

Appendix_Area: attached body-moisture meter area (m ²)

Abt: ball bow area of section (m ²)

Wherein, the value of Cb, Cwp, Cm is design or to obtain the resistance process be given parameter value, ship design finish or build finish after these three coefficients be to determine to exist, can obtain by calculating.Appendix_Area, Abt and above-mentioned three coefficients are similar, also are to utilize the method for prior art to obtain by calculating directly after ship design or the construction.And speed of a ship or plane V is given value, and is relevant with resistance to be calculated.

Corresponding ship type and state (designed draft/ballast draft state) that step 2, selection will be calculated;

Step 3, Ship ' wetted surface area;

Boats and ships wetted surface area computing formula is as follows:

$S=\mathrm{Lwl}(2T+B){C_m}^{0.5}(0.3696C_{\mathrm{wp}}+0.453+0.4425C_b-0.2862C_m-0.003467\frac{B}{T})$

$+2.38\frac{\mathrm{Abt}}{C_b}+\mathrm{Appendix}\_\mathrm{Area}$

Wherein: S: boats and ships wetted surface area (m ²);

Step 4, calculating friction drag, wave making resistance;

1), Froude number Fn computing formula is as follows:

L _fn＝L _os L _os＜1

L _fn＝L+2/3(L _os-L) 1≤L _os/L＜1.1

L _fn＝1.0667L 1≤L _os/L＜1.1

F _n＝V/(L _fng) ^1/2

Wherein: L: calculate captain (m), be taken as Lbp

G: acceleration due to gravity (m/s ²)

2), friction drag is calculated as follows:

R _n＝VL _os/γ

C _f＝0.075/(log ₁₀R _n-2) ²

R _f＝0.5C _fSρV ²

Wherein: γ: water movement coefficient of viscosity (m ²/ s)

ρ: the density (kg/m of water ³)

3), residuary resistance is calculated as follows:

R _Rmean＝0.5C _R(0.1BT)ρV ²

R _Rmin＝0.5C _Rmin(0.1BT)ρV ²

C _R＝C _R1C _R2K _L(T/B) ^b1(B/L) ^b2(L _os/L _wl) ^b3(L _wl/L) ^b4

(1+(T _A-T _F)/L) ^b5(D _P/T _A) ^b6

C _Rmin＝C _R1(T/B) ^b1(B/L) ^b2(L _os/L _wl) ^b3(L _wl/L) ^b4

(1+(T _A-T _F)/L) ^b5(D _P/T _A) ^b6

Wherein:

$C_{R1}=c_{11}+c_{12}{F}_n+c_{13}{F}_n^2+C_B(c_{21}+c_{22}{F}_n+c_{23}{F}_n^2)$

$+C_B^2(c_{31}+c_{32}{F}_n+c_{33}{F}_n^2)$

C _R2＝max(1.0，(F _n/F _n1) ^f1)

$F_{n1}=d_1+d_2{C}_B+d_3{C}_B^3$

K _L＝e ₁L ^e2

Wherein: the parameter in the formula sees the following form:

	Designed draft CR	Designed draft CRmin	Ballast draft CR
				b1	-0.3382	-0.3382	-0.7139
b2	0.8086	0.8086	0.2258
				b3	-6.0258	-6.0258	-1.1606
b4	-3.5632	-3.5632	0.4534
				b5	9.4405	0	11.222
b6	0.0146	0	0.4524
				c11	-0.5742	-0.91424	-1.5016
c12	13.3893	13.3893	12.9578
				c13	90.5960	90.596	-36.7985
c21	4.6614	4.6614	5.5553
				c22	-39.721	-39.721	-45.8815
c23	-351.483	-351.483	121.820
				c31	-1.14215	-1.14215	-4.3357
c32	-12.3296	-12.3296	36.0782
				c33	459.254	459.254	-85.3741
d1	0.854	0	0.032
				d2	-1.228	0	0.803
d3	0.497	0	-0.739
				e1	2.1701	0	1.9994

e2

-0.1602

0

-0.1446

Step 5, calculating total drag.

Designed draft state total drag (N):

R _t＝0.5(R _Rmin+1.204R _Rmean)+R _f

Ballast draft state total drag (N):

R _t＝1194R _Rmean+R _f

This method of calculating, by with real ship model Experimental Comparison, total drag obtains the result and the model test result compares, two results differ and can be controlled in about 3-5%, and therefore, the method that the present invention obtains resistance has accurately characteristics of Simple fast, simultaneously, its result and truth are very approaching, can be directly as testing result, or be used for instructing ship design at design phase.Ship resistance was calculated when this method was particularly useful for conventional single-blade box ship preliminary design.Specifically can be referring to following Example Verification

Take the 4250TEU box ship of Dalian Shipping Heavy Industry Group Co., Ltd.'s design-build as example, as follows with the model test contrast:

The principal dimensions of boats and ships and other correlation parameter are as follows:

	Designed draft	Ballast draft
			Lbp(m)	244.5	244.5
Los(m)	257.14	257.55
			Lwl(m)	244.14	241.34
B(m)	32.25	32.25
			T(m)	11.0	6.2
Ta(m)	11.0	8.4
			Tf(m)	11.0	4.0
Dp(m)	7.75	7.75
			Cb	0.632	0.559
Cwp	0.815	0.689
			Cm	0.976	0.962
Appendix_Area(m 2)	75	75
			Abt(m 2)	22	15

Designed draft (Design Speed 24.5kn) total drag synopsis:

Ballast draft total drag synopsis:

According to the method for above-mentioned acquisition ship resistance, the present invention also provides the method for designing in a kind of ship design stage, and detailed process comprises:

At first, tentatively determine principal dimensions and other correlation parameter (referring to the above description of step 1) of boats and ships.

After this, referring to step 2-5 above, calculate total drag.

Again, the result according to total drag calculates revises scale dependent and parameter in the step 1, and referring again to above, step 2-5 calculates total drag.

At last, by repeatedly revising scale dependent and parameter, the result of more each total drag.Finally, according to concrete application and the demand of boats and ships, choose a scale dependent and parameter suitable, and the design conditions of total drag value minimum.So-called scale dependent and parameter are suitable to be referred to satisfy the application of specific ship and subscribes the requirement of making the boats and ships client.

Above-mentioned ship design process has improved the efficient of prior art design process greatly, and the result of calculation of total drag can be effective to the ship design stage more near real ship situation.

The above; only be the better specific embodiment of the present invention; but protection scope of the present invention is not limited to this; anyly be familiar with those skilled in the art in the technical scope that the present invention discloses; be equal to replacement or change according to technical scheme of the present invention and inventive concept thereof, all should be encompassed within protection scope of the present invention.

Claims (1)

1. a method of obtaining box ship boats and ships resistance is characterized in that, comprises the steps: S1, by design or measure principal dimensions and the following parameter obtain boats and ships:

Length between perpendiculars Lbp, unit: rice;

Waterline overall length Los, unit: rice;

Length on water line Lwl, unit: rice;

Molded breadth B, unit: rice;

Drinking water T, unit: rice;

Aft draft Ta, unit: rice;

Draught forward Tf, unit: rice;

Diameter of propeller Dp, unit: rice;

Obtain following parameter by design or calculating:

Block coefficient Cb;

Coefficient of waterplane Cwp;

Midship section coefficient Cm;

Speed of a ship or plane V, unit: meter per second;

Attached body-moisture meter area A ppendix_Area, unit: sq m;

Ball bow area of section Abt, unit: sq m;

S2, according to following formula Ship ' wetted surface area S, unit: sq m;

$S=\mathrm{Lwl}(2T+B){C_m}^{0.5}(0.3696C_{\mathrm{wp}}+0.453+0.4425C_b-0.2862C_m-0.003467\frac{B}{T})$

$+2.38\frac{\mathrm{Abt}}{C_b}+\mathrm{Appendix}\_\mathrm{Area}$

S3, calculating friction drag, wave making resistance comprise the steps;

1) calculate Froude number Fn:

At first, calculate L according to the size of Los _Fn

L _fn＝L _os L _os＜1

L _fn＝L+2/3(L _os-L) 1≤L _os/L＜1.1

L _Fn=1.0667L 1≤L _Os/ L＜1.1; Wherein, L=Lbp;

Then calculate F _n=V/ (L _FnG) ^1/2, wherein, g is acceleration due to gravity, unit: m/s ²

2) friction drag is calculated as follows:

R _n＝VL _os/γ

C _f＝0.075/(log ₁₀R _n-2) ²

R _f＝0.5C _fSρV ²

Wherein: water movement coefficient of viscosity γ, unit: m ²/ s;

The density p of water, unit: kg/m ³

S4, calculating residuary resistance:

R _Rmean＝0.5C _R(0.1BT)ρV ²

R _Rmin＝0.5C _Rmin(0.1BT)ρV ²

C _R＝C _R1C _R2K _L(T/B) ^b1(B/L) ^b2(L _os/L _wl) ^b3(L _wl/L) ^b4

(1+(T _A-T _F)/L) ^b5(D _P/T _A) ^b6

C _Rmin＝C _R1(T/B) ^b1(B/L) ^b2(L _os/L _wl) ^b3(L _wl/L) ^b4

(1+(T _A-T _F)/L) ^b5(D _P/T _A) ^b6

Wherein:

$C_{R1}=c_{11}+c_{12}{F}_n+c_{13}{F}_n^2+C_B(c_{21}+c_{22}{F}_n+c_{23}{F}_n^2)$

$+C_B^2(c_{31}+c_{32}{F}_n+c_{33}{F}_n^2)$

C _R2＝max(1.0，(F _n/F _n1) ^f1)

$F_{n1}=d_1+d_2{C}_B+d_3{C}_B^3$

K _L＝e ₁L ^e2

In addition, the parameter in the above-mentioned formula is according to ship type and drinking water/ballast draft state, and ginseng is determined according to following table:

Designed draft CR Designed draft CRmin Ballast draft CR b1 -0.3382 -0.3382 -0.7139 b2 0.8086 0.8086 0.2258 b3 -6.0258 -6.0258 -1.1606 b4 -3.5632 -3.5632 0.4534 b5 9.4405 0 11.222 b6 0.0146 0 0.4524 c11 -0.5742 -0.91424 -1.5016 c12 13.3893 13.3893 12.9578 c13 90.5960 90.596 -36.7985 c21 4.6614 4.6614 5.5553 c22 -39.721 -39.721 -45.8815 c23 -351.483 -351.483 121.820 c31 -1.14215 -1.14215 -4.3357 c32 -12.3296 -12.3296 36.0782

c33 459.254 459.254 -85.3741 d1 0.854 0 0.032 d2 -1.228 0 0.803 d3 0.497 0 -0.739 e1 2.1701 0 1.9994 e2 -0.1602 0 -0.1446

S5, according to ship type described in the step S4 and drinking water/ballast draft state, utilize the total drag of the corresponding calculating of following formula drinking water state or ballast draft state:

Drinking water state total drag R _t=0.5 (R _Rmin+ 1.204R _Rmean)+R _f, unit: N;

Ballast draft state total drag R _t=1194R _Rmean+ R _f, unit: N.

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