CN102998083A - Method for obtaining platform actual wind load through self-elevating drilling platform wind tunnel test - Google Patents

Abstract

The invention discloses a method for obtaining platform actual wind load through a self-elevating drilling platform wind tunnel test. The main theory is that the wind tunnel test is divided into an on-water portion and an underwater portion, test results comprise on-water portion data results and an underwater portion data results in each wind directional angle and are given a dimensionless mode, and the test results comprise dimensionless coefficients of force and moment in the horizontal direction, the longitudinal direction and the vertical direction. The method is used for analyzing the wind tunnel test of all self-elevating drilling platforms or similar platforms, and the method is simple in process and improves work efficiency. By means of rapid determination of wind heeling moment of the self-elevating drilling platforms, efficiency of stability analysis can be improved, and cost is saved.

Description

Obtain the method for the actual wind load of platform by the self-elevating drilling platform wind tunnel test

Technical field

The present invention relates to a kind of marine engineering design field, more particularly, relate to determining for the drilling platform wind load of stability analysis.

Background technology

For obtaining mainly by two kinds of methods of wind heeling moment: proper calculation and wind tunnel test.Each classification society rule in the detail property of there are differences, affects meeting and calculated case to some extent difference such as what whether consider the many factors such as capture-effect, turbulent flow, boundary layer for the wind load computing formula, need take into account device structure the level of detail of wind load etc.In addition, according to the wind load that the coefficient of modular formula and recommendation calculates, the same yardstick self-elevating platform (SEP) product of contrast design abroad company, obviously higher.

Waterborne when as shown in Figure 2, being in free drifting state for platform, stressed synoptic diagram under water.D among the figure _AwFor above water stressed, D _UwFor underwater portion stressed, H _AwBe the above water arm of force, H _UwBe the underwater portion arm of force, M _tBe the total wind heeling moment of platform according to above-mentioned parameter conversion gained.

For self-elevating drilling platform, wind load is greater than the impact of wave and ocean current on the impact of platform.The motion of self-elevating drilling platform is comparatively complicated under the towage operating mode, and its load that suffers mainly contains the kinetic inertial load of platform, deadweight and wind load etc.The wind load that calculates according to modular formula occupies 40%～50% of self-elevating platform (SEP) environmental load approximately, is that the important performance of self-elevating platform (SEP) stability and structural strength affects parameter.As seen, comparatively reasonably determining the wind load of drilling platform, is that drilling platform optimal design and platform are to the task of top priority of deep-water developments.

Summary of the invention

The present invention is the method that the self-elevating drilling platform results of wind tunnel is applied to real ship.By determining the quick of self-elevating platform (SEP) wind heeling moment, can improve the efficient of stability analysis, save cost.

In order to achieve the above object, the invention provides a kind of method by the actual wind load of self-elevating drilling platform wind tunnel test acquisition platform, comprise the steps:

S1, be that self-elevating drilling platform sets coordinate system, flat surface is the XY plane, and vertical described flat surface is Z axis;

S2, design, measurement, and obtain data by wind tunnel test, and obtain parameter with following a-f formula:

Wind tunnel test be divided into waterborne and under water two parts carry out, test findings provides respectively waterborne under the wind angle ψ and two-part data result under water with nondimensional form, comprise the dimensionless factor of the force and moment of level, vertical, vertical three directions, be denoted as respectively as follows:

A) longitudinal force coefficient: $X^{\′}=\frac{X}{1/2\·\mathrm{\ρ}{U}^2{L}_{\mathrm{PP}}^2}$

B) cornering ratio: $Y^{\′}=\frac{Y}{1/2\·\mathrm{\ρ}{U}^2{L}_{\mathrm{PP}}^2}$

C) vertical force coefficient: $Z^{\′}=\frac{Z}{1/2\·\mathrm{\ρ}{U}^2{L}_{\mathrm{PP}}^2}$

D) heeling moment coefficient: $K^{\′}=\frac{K}{1/2\·\mathrm{\ρ}{U}^2{L}_{\mathrm{PP}}^3}$

E) Trimming Moment coefficient: $M^{\′}=\frac{M}{1/2\·\mathrm{\ρ}{U}^2{L}_{\mathrm{PP}}^3}$

F) torque coefficient: $N^{\′}=\frac{N}{1/2\·\mathrm{\ρ}{U}^2{L}_{\mathrm{PP}}^3}$

Wherein symbol description and unit are as follows

Wherein, the arm of force should be from total wind-engaging surface pressing center be vertically measured meter to this platform underwater case center of lateral resistance; And the centre of draft of underwater portion is got half that do drinking water usually;

Calculate obtaining parameter comprises: according to design or the calculation of parameter measured obtain platform parameter X waterborne ' _Aw, Y ' _Aw, K ' _Aw, M ' _Aw, and platform under water parameter X ' _Uw, Y _u' _w, K ' _Uw, M ' _Uw

Test obtains parameter and comprises: Z ' _Aw, N ' _Aw, Z ' _Uw

Wherein, subscript aw is parameter waterborne, and subscript uw is parameter under water;

S3, the data of utilizing S2 to obtain according to following formula, obtain wind heeling moment M corresponding under the described wind angle ψ _t:

The above water wind arm H that goes all out _Aw, unit is m:

$H_{\mathrm{aw}}=\frac{-K_{\mathrm{aw}}^{\′}\·\sin (180-\mathrm{\ψ})+M_{\mathrm{aw}}^{\′}\·\cos (180-\mathrm{\ψ})}{X_{\mathrm{aw}}^{\′}\·\cos (180-\mathrm{\ψ})+Y_{\mathrm{aw}}^{\′}\·\sin (180-\mathrm{\ψ})}{L}_{\mathrm{pp}}$

The underwater portion wind arm H that goes all out _Uw, unit is m:

$H_{\mathrm{uw}}=\frac{-K_{\mathrm{uw}}^{\′}\·\sin (-\mathrm{\ψ})+M_{\mathrm{uw}}^{\′}\·\cos (-\mathrm{\ψ})}{X_{\mathrm{uw}}^{\′}\·\cos (-\mathrm{\ψ})+Y_{\mathrm{uw}}^{\′}\·\sin (-\mathrm{\ψ})}{L}_{\mathrm{pp}}$

Waterborne stressed, i.e. wind-force D _Aw, unit is N:

D _aw=X _aw·cos(180-ψ)+Y _aw·sin(180-ψ)

Stressed D under water _Uw, unit is N:

D _uw=X _uw·cos(-ψ)+Y _uw·sin(-ψ)

The wind heeling moment M that platform is total _t, unit is Nm:

M _t=(|H _aw|+H _uw)·D _aw

S4, given various wind angle ψ repeat S2-S3 and obtain corresponding wind heeling moment M _t

By above-mentioned steps, the wind heeling moment M corresponding to various wind angle ψ that step S4 can be obtained _tBe used for stability analysis.

The present invention relates to the method that a kind of self-elevating drilling platform results of wind tunnel is applied to the actual wind load of platform, its cardinal principle be wind tunnel test be divided into waterborne and under water two parts carry out, test findings provides respectively waterborne under each wind direction angle and two-part data result under water with nondimensional form, comprises the dimensionless factor of the force and moment of level, vertical, vertical three directions.Use this method that all self-elevating drilling platforms or similar platform wind tunnel test are analyzed, process is very easy, has greatly improved work efficiency.

Description of drawings

Fig. 1 is wind tunnel test coordinate synoptic diagram;

Fig. 2 is waterborne when being in free drifting state, the stressed synoptic diagram under water of platform.

Embodiment

The present invention is the method that the self-elevating drilling platform results of wind tunnel is applied to the actual wind load of platform, by the self-elevating drilling platform results of wind tunnel being applied to the method for the actual wind load of platform, needed wind heeling moment value when obtaining fast actual platform calculating stability.The dimensionless factor of the force and moment of the platform above water that records by test specifically, and the level of underwater portion, vertical, vertical three directions and the wind load numerical value that relevant reduction formula obtains actual platform.Detailed process of the present invention is as follows:

As shown in Figure 1, set coordinate system for self-elevating drilling platform, flat surface is the XY plane, and vertical described flat surface is Z axis.ψ is wind angle, and TRIM is the platform inclination direction, and K, M, N are respectively platform moment corresponding to X-axis, Y-axis, Z axis under the wind-force effect.Wind tunnel test be divided into waterborne and under water two parts carry out, test findings provides respectively waterborne under each wind direction angle and two-part data result under water with nondimensional form, comprise the dimensionless factor of the force and moment of level, vertical, vertical three directions, be denoted as respectively as follows:

A) longitudinal force coefficient: $X^{\′}=\frac{X}{1/2\·\mathrm{\ρ}{U}^2{L}_{\mathrm{PP}}^2}$

B) cornering ratio: $Y^{\′}=\frac{Y}{1/2\·\mathrm{\ρ}{U}^2{L}_{\mathrm{PP}}^2}$

C) vertical force coefficient: $Z^{\′}=\frac{Z}{1/2\·\mathrm{\ρ}{U}^2{L}_{\mathrm{PP}}^2}$

D) heeling moment coefficient: $K^{\′}=\frac{K}{1/2\·\mathrm{\ρ}{U}^2{L}_{\mathrm{PP}}^3}$

E) Trimming Moment coefficient: $M^{\′}=\frac{M}{1/2\·\mathrm{\ρ}{U}^2{L}_{\mathrm{PP}}^3}$

F) torque coefficient: $N^{\′}=\frac{N}{1/2\·\mathrm{\ρ}{U}^2{L}_{\mathrm{PP}}^3}$

Symbolic interpretation sees Table 1 in the formula.

Table 1 symbol description and unit

According to code requirement, when wind heeling moment calculated, its arm of force should be from total wind-engaging surface pressing center be vertically measured meter to this platform underwater case center of lateral resistance.Employing is during based on the wind load of formula, and the centre of draft of underwater portion is got half that do drinking water usually.Use the wind tunnel test data, then the wind that calculates respectively above water and the underwater portion arm of going all out determines total wind heeling moment according to the wind load size of actual measurement.

The X ' that is used for calculating in the following formula _Aw, Y ' _Aw, K ' _Aw, M ' _AwBe platform parameter waterborne, X ' _Uw, Y ' _Uw, K ' _Uw, M ' _UwBe platform parameter under water, the Z ' that test obtains _Aw, N ' _Aw, Z ' _Uw, N ' _UwOnly for reference, do not participate in wind heeling moment and calculate, ψ represents the wind direction angle.

It is as follows that the self-elevating drilling platform results of wind tunnel is converted to the concrete grammar of real ship:

The above water wind arm H that goes all out _Aw, unit is m:

$H_{\mathrm{aw}}=\frac{-K_{\mathrm{aw}}^{\′}\·\sin (180-\mathrm{\ψ})+M_{\mathrm{aw}}^{\′}\·\cos (180-\mathrm{\ψ})}{X_{\mathrm{aw}}^{\′}\·\cos (180-\mathrm{\ψ})+Y_{\mathrm{aw}}^{\′}\·\sin (180-\mathrm{\ψ})}{L}_{\mathrm{pp}}$

The underwater portion wind arm H that goes all out _Uw, unit is m:

$H_{\mathrm{uw}}=\frac{-K_{\mathrm{uw}}^{\′}\·\sin (-\mathrm{\ψ})+M_{\mathrm{uw}}^{\′}\·\cos (-\mathrm{\ψ})}{X_{\mathrm{uw}}^{\′}\·\cos (-\mathrm{\ψ})+Y_{\mathrm{uw}}^{\′}\·\sin (-\mathrm{\ψ})}{L}_{\mathrm{pp}}$

Waterborne stressed, i.e. wind-force D _Aw, unit is N:

D _aw=X _aw·cos(180-ψ)+Y _aw·sin(180-ψ)

Stressed D under water _Uw, unit is N:

D _uw=X _uw·cos(-ψ)+Y _uw·sin(-ψ)

The wind heeling moment M that platform is total _t, unit is Nm:

M _t=(|H _aw|+H _uw)·D _aw

Conversion obtains the different wind heeling moment M of the correspondence under each different position angle wind angle ψ _tAfter, namely can be used as the input data platform stability is calculated.

Preferred embodiment: be that example describes the present invention below in conjunction with certain platform.

Test findings provides respectively waterborne under each wind direction angle and two-part data result under water with nondimensional form, comprises the dimensionless factor of the force and moment of level, vertical, vertical three directions, and the result is as follows:

The above water result:

Ψ	X′	Y′	Z′	K′	M′	N′
							[°]	[-]	[-]	[-]	[-]	[-]	[-]
0	-0.9074	0.0124	-0.2264	0.0020	0.8032	0.0200
							10	-0.8965	0.2134	-0.2399	0.1586	0.7963	0.0188
20	-0.8340	0.3888	-0.2456	0.2900	0.7318	0.0122
							30	-0.7428	0.5488	-0.2641	0.4110	0.6525	0.0056
40	-0.6850	0.7169	-0.2892	0.5303	0.6041	0.0042
							50	-0.6039	0.8492	-0.3011	0.6076	0.5438	0.0040

The underwater portion result:

Ψ	X′	Y′	Z′	K′	M′	N′
							[°]	[-]	[-]	[-]	[-]	[-]	[-]
0	0.0717	0.0000	0.1386	0.0000	0.0340	0.0000
							10	0.0699	-0.0072	0.1355	-0.0006	0.0329	-0.0002
20	0.0641	-0.0143	0.1275	-0.0003	0.0304	-0.0006
							30	0.0571	-0.0225	0.1176	0.0012	0.0255	0.0001
40	0.0464	-0.0291	0.1072	0.0037	0.0211	0.0004
							50	0.0384	-0.0355	0.1039	0.0076	0.0134	0.0002

The wind tunnel that conversion obtains according to the above water result:

Ψ	Xaw	Yaw	Daw	Kaw	Maw	Haw
							[°]	[N]	[N]	[N]	[Nm]	[Nm]	[m]
0	-3796736	51884	3796736	607963	244157983	64.3
							10	-3751128	892907	3849192	48211474	242060510	64.1
20	-3489616	1626814	3835570	88154650	222453700	62.4
							30	-3108018	2296285	3839765	124936418	198347963	61.0
40	-2866172	2999647	4123751	161201417	183635256	59.2
							50	-2526834	3553216	4346139	184699191	165305168	57.0

The wind tunnel that conversion obtains according to the underwater portion result:

Ψ	Xuw	Yuw	Duw	Kuw	Muw	Huw
							[°]	[N]	[N]	[N ]	[Nm]	[Nm]	[m]
0	300007	0	300007	0	10335373	34.5
							10	292475	-30126	293263	-182389	10000993	33.5
20	268207	-59834	272496	-91194	9241039	31.8
							30	238917	-94144	253981	364778	7751530	27.1
40	194147	-121760	226991	1124732	6414011	24.8
							50	160673	-148539	217066	2310260	4073353	20.2

Then convert according to above wind tunnel and obtain the suffered wind heeling moment of platform:

Ψ	Mt
		[°]	[tm]
0	38222.0
		10	38288.7
20	36797.1
		30	34504.6
40	35340.2
		50	34210.3

Above result has been arranged, and namely can be used as the input data can calculate the platform stability.

The above; only be the better 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 (2)

1. the method by the actual wind load of self-elevating drilling platform wind tunnel test acquisition platform is characterized in that, comprises the steps:

S1, be that self-elevating drilling platform sets coordinate system, flat surface is the XY plane, and vertical described flat surface is Z axis;

S2, design, measurement, and obtain data by wind tunnel test, and obtain parameter with following a-f formula:

Wind tunnel test be divided into waterborne and under water two parts carry out, test findings provides respectively waterborne under the wind angle ψ and two-part data result under water with nondimensional form, comprise the dimensionless factor of the force and moment of level, vertical, vertical three directions, be denoted as respectively as follows:

A) longitudinal force coefficient: $X^{\′}=\frac{X}{1/2\·\mathrm{\ρ}{U}^2{L}_{\mathrm{PP}}^2}$

B) cornering ratio: $Y^{\′}=\frac{Y}{1/2\·\mathrm{\ρ}{U}^2{L}_{\mathrm{PP}}^2}$

C) vertical force coefficient: $Z^{\′}=\frac{Z}{1/2\·\mathrm{\ρ}{U}^2{L}_{\mathrm{PP}}^2}$

D) heeling moment coefficient: $K^{\′}=\frac{K}{1/2\·\mathrm{\ρ}{U}^2{L}_{\mathrm{PP}}^3}$

E) Trimming Moment coefficient: $M^{\′}=\frac{M}{1/2\·\mathrm{\ρ}{U}^2{L}_{\mathrm{PP}}^3}$

F) torque coefficient: $N^{\′}=\frac{N}{1/2\·\mathrm{\ρ}{U}^2{L}_{\mathrm{PP}}^3}$

Wherein:

Sequence number Symbol Title Unit (Chinese) Unit (English) 1 X Longitudinal force (directions X) Newton N 2 Y Transverse force (Y-direction) Newton N 3 Z Vertical force (Z direction) Newton N 4 K Heeling moment (around X-axis) Newton meter Nm 5 M Trimming Moment (around Y-axis) Newton meter Nm 6 N Moment of torsion (around Z axis) Newton meter Nm 7 ρ Air specific weight=1.21 Kg/m ³ kg/m ³ 8 U Wind speed Meter per second m/s 9 L _pp Main hull length Rice m

In addition, the arm of force should be from total wind-engaging surface pressing center be vertically measured meter to this platform underwater case center of lateral resistance; And the centre of draft of underwater portion is got half that do drinking water usually;

Calculate obtaining parameter comprises: according to design or the calculation of parameter measured obtain platform parameter X waterborne ' _Aw, Y ' _Aw, K ' _Aw, M ' _Aw, and platform under water parameter X ' _Uw, Y ' _Uw, K ' _Uw, M _Uw

Test obtains parameter and comprises: Z ' _Aw, N ' _Aw, Z ' _Uw

Wherein, subscript aw is parameter waterborne, and subscript uw is parameter under water;

S3, the data of utilizing S2 to obtain according to following formula, obtain wind heeling moment M corresponding under the described wind angle ψ _t:

The above water wind arm H that goes all out _Aw, unit is m:

$H_{\mathrm{aw}}=\frac{-K_{\mathrm{aw}}^{\′}\·\sin (180-\mathrm{\ψ})+M_{\mathrm{aw}}^{\′}\·\cos (180-\mathrm{\ψ})}{X_{\mathrm{aw}}^{\′}\·\cos (180-\mathrm{\ψ})+Y_{\mathrm{aw}}^{\′}\·\sin (180-\mathrm{\ψ})}{L}_{\mathrm{pp}}$

The underwater portion wind arm H that goes all out _Uw, unit is m:

$H_{\mathrm{uw}}=\frac{-K_{\mathrm{uw}}^{\′}\·\sin (-\mathrm{\ψ})+M_{\mathrm{uw}}^{\′}\·\cos (-\mathrm{\ψ})}{X_{\mathrm{uw}}^{\′}\·\cos (-\mathrm{\ψ})+Y_{\mathrm{uw}}^{\′}\·\sin (-\mathrm{\ψ})}{L}_{\mathrm{pp}}$

Waterborne stressed, i.e. wind-force D _Aw, unit is N:

D _aw=X _aw·cos(180-ψ)+Y _aw·sin(180-ψ)

Stressed D under water _Uw, unit is N:

D _uw=X _uw·cos(-ψ)+Y _uw·sin(-ψ)

The wind heeling moment M that platform is total _t, unit is Nm:

M _t=(|H _aw|+H _uw)·D _aw

S4, given various wind angle ψ repeat S2-S3 and obtain corresponding wind heeling moment M _t

2. describedly according to claim 1 obtain the method for the actual wind load of platform by the self-elevating drilling platform wind tunnel test, it is characterized in that, with the wind heeling moment M corresponding to various wind angle ψ of step S4 acquisition _tBe used for stability analysis.

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