The computational simulation in the design of ship ...

The computational simulation in the design of ship piping systems Daniel Molina Pérez e-mail: [email protected] Centro de Investigaciones Hidráulicas (CIH), Universidad Tecnológica de La Habana José Antonio Echeverría (Cujae), Habana Amadelis Quesada Torres e-mail: [email protected] Empresa de Proyectos e Investigaciones Hidráulicas de La Habana, Habana Lemuel C. Ramos-Arzola e-mail: [email protected] Centro de Investigaciones Hidráulicas (CIH), Universidad Tecnológica de La Habana José Antonio Echeverría (Cujae), Habana

ABSTRACT Ship piping systems are pipe networks which intervene in most of the functions of a ship. This paper describes the design of a bilge and fire protection system for a ship, which is simulated with the EPANET software, in order to demonstrate the feasibility of the design of marine hydraulic systems based on computational simulation. It is concluded that integrating simulation to the design of these networks allows to configure systems so that the flow variables are within the recommended ranges and regulations; enables recreation of different system scenarios as well as variants analysis and gradual design; prevents selection of oversized or erroneous components which makes possible the optimization of weights and costs of the systems. Keywords: EPANET, simulation of naval systems, fire protection systems on ships, bilge systems, piping systems on ships.

La simulación en el diseño de los sistemas hidráulicos navales RESUMEN Los sistemas hidráulicos navales son redes de tuberías que intervienen en la mayoría de las funciones de una embarcación. Este trabajo desarrolla el diseño de un sistema de achique y contraincendios de un buque, para lo cual se emplea el software EPANET, con el objetivo de demostrar la factibilidad del diseño de sistemas hidráulicos navales basado en la simulación computacional. Se concluye que la simulación integrada al diseño de estas redes, permite configurar los sistemas de manera que las variables de flujo se encuentren dentro de los rangos recomendables y reglamentarios; posibilita la recreación de diferentes escenarios del sistema, así como el análisis de variantes y el diseño gradual; evita la selección de componentes sobredimensionados o erróneos, lo que viabiliza la optimización de pesos y costos de los sistemas. Palabras clave: EPANET, simulación de sistemas navales, sistemas contraincendios en buques, sistemas de achique, sistemas de tuberías en buques

This is the translated version of the original article “La simulación en el diseño de los sistemas hidráulicos navales” Ingeniería Hidráulica y Ambiental, VOL. XXXVIII, No. 2, May-Ago 2017, p.29-43, ISSN: 1815–591X

INTRODUCTION At the beginning of the 20th century, piping systems were designed based on intuitive rules and conservatism. Analog methods reached in the mid-twentieth century, to be replaced by the computational simulation of piping systems that originated in 1957 (Walski 2006). Simulating a piping system - finding the distribution of flows and pressures - can mean finding hundreds of nonlinear equations solutions simultaneously, i.e. the solution of a nonlinear equations system. Ship piping systems are networks that play a role in most vessel functions and can account for a significant share of the cost and total weight of a ship (Asmara 2013). These networks can carry gas, fuel, lubricating oil and cooling water for the machines. For human comfort there are systems of potable water, water vapor and sewage, among others. For protection and safety there are fire, bilge and ballast systems. These systems generally comprise elements such as pipes, tanks, valves, accessories, pumps, heat exchangers, emitters, sensors, ejectors, actuators, among others. The design of the ship piping systems is produced gradually, gaining in detail and precision as the project stages progress. This is because the specialist at first does not have all the required information that allows the network simulation. On the other hand, the gradual design is oriented to guarantee the recommended ranges of flow variables (flow and pressure), to ensure compliance with the rules of ship classification societies, to reduce the costs and weights of the systems, to establish better distributions of the same, among others (Asmara 2013). Thus, the design of a ship piping system requires multiple modifications and simulations, so it is necessary to solve several times the set of governing equations. For these reasons ship piping systems are among the most complex design elements of a vessel (Cassee 1992). EPANET is a computer program for the analysis of water distribution systems. Although in general it can be used for the analysis of non-compressible fluid with pressure flow. The program allows hydraulic analyzes of piping networks based on the characteristics of the elements that compose the system, to obtain pressure and flow rates in nodes and pipes respectively (Rossman 2001). This paper describes the design of a bilge system (BS) and fire protection system (FPS) for a port tug, which is simulated with the EPANET software, in order to demonstrate the feasibility of designing ship piping systems based on computational simulation. It is concluded that integrating simulation to the design of these networks allows to configure systems so that the flow variables are within the recommended ranges and regulations; enables recreation of different system scenarios as well as variants analysis and gradual design; prevents selection of oversized or erroneous components which makes possible the optimization of weights and costs of the systems. BILGE SYSTEM The BS's constitutes a safety system of the boats. These systems must be able to pump and drain water from any watertight compartment that is not permanently dedicated to contain water, fuel, oil or any other type of liquid. The water to be extracted can enter the interior of the ship due to various causes such as sea blows, leaks in piping systems, faults, among others.

FIRE PROTECTION SYSTEM FPS's are essential systems for fire extinguishing in boats. These safety systems pump sea water to different points on the ship where firepower, nozzles, sprinklers, among others. Water FPS's are very effective because of their cooling capacity, thus preventing explosions of combustible materials and mitigating the spread of fire. CUBAN SHIP REGISTERY Cuban Ship Registry (2006), RCB in Spanish, is a classification society formed by an independent organization of technical experts. It presents a set of rules applicable to all the parts or elements that make up a ship. These rules govern the current state of knowledge related to the shipping industry and are applied by the registry in the classification and technical supervision of ships.

GENERAL CHARACTERISTICS OF THE TUG RAD II The RAD II is a port tug with a hull and steel hut. It has a single deck and five watertight compartments, see figure 1. Table 1 shows the general characteristics of this boat.

RCB RULES The following are some of the RCB (2006) rules applied to the design of the BS and the FPS, whose compliance constitutes, in part, the essence of subsequent design. Some rules that by their extension could divert attention from the main aspects of the work have been omitted. Table 1. General characteristics of the tug RAD RII Total length

15,48 meters

Floating length

11 meters

Beam

4,6 meters

Design depth

1,75 meters

Draft

1,4 meters

Maximum displacement

58,4 ton

Maximum speed

8 knots

Main machines

2x148 kW

Category according to the navigation area

III inside port

Profile Perfil view

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1

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29

Planta Plan view Arriba: sobre De abajo: bajodeck cubierta. Up: Over deckcubierta. Down: Under

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26

Sector de los Timones Espacio vacio

Maquinas

Combustible

Figure 1. Disposition plan of the tug RAD II

Pañol

Espacio vacio

27

28

29

RCB rules applied to the bilge system design of RAD II. 1. Each self-propelled ship shall have not less than two bilge pumps with mechanical drive. 2.

In ships of restricted navigation areas II and III, as well as in other ship up to 25 meters of length, one of the bilge pumps may be driven by the main engine and the other may be an ejector or a hand pump.

3. Each bilge pump required shall have a capacity such that the velocity, in the water main, whose diameter is calculated by equation (1), under normal operating conditions, it shall not be less than 2 m / s. 𝑑1 = 1,68√𝐿(𝐵 + 𝐷) + 25 (1) 4. where: L, B, D: length, beam and depth respectively, in meters; d1: diameter, in millimeters. 5. For the diameters of the suction branches the formula is as follows: 𝑑0 = 2,15√𝑙(𝐵 + 𝐷) + 25

(2)

where: l: bilged space (length of bilged compartment), in meters; d0: diameter, in millimeters. 6. The chest valves and branches (so that water is not communicated from one compartment to another) must be fitted with check valves. 7. In the suction of bilge compartments outside the spaces of machines and tunnels install grids with holes no larger than 10 mm in diameter. The total area of these holes should be at least twice as large as the cross-sectional area of the suction. RCB rules applied to the fire protection system design of RAD II 1. For ships with a tonnage less than 300 GRT (gross register tonnage), at least one fire-fighting pump is required to produce a minimum pressure of 0.2 MPa at the fire connections, operating simultaneously. 2. The total capacity of stationary fire pumps, with the exception of emergency pumps (if any) with a pressure at any fire connection not less than specified in regulation 1, shall guarantee a water flow (with fire nozzle in operation) no less than determined by equation (3). 𝑄 = 𝐶𝑃 ∗ 𝑚2

(3)

where: Q: flow rate in m3/h; CP: no dimensional coefficient, which depends of the ship compartmentalization, by RAD II CP=0,008; m is given by (4):

𝑚 = 1,68√𝐿2 (𝐵 + 𝐷) + 25

(4)

where: L2: compartment length (except those without flammable materials), in meters. 3. Each stationary fire pump shall be calculated for at least two jets of water, with the highest nozzle diameter taken for the ship in question. 4. The location of the fire connections shall allow the quick and easy attachment of the fire hoses and their quantity shall ensure the supply of two streams of water to any place of the ship. 5. Fire hoses must comply with the following requirements: (i) have a length between 15 and 20 meters from the fire connections, located on exterior deck, and approximately 15 meters from the fire connections in the spaces (ii) The hoses together with the nozzles must be located next to the fire connections on spools or placed inside special boxes. 6. For ships with a gross tonnage of less than 150 GRT, nozzles of 10, 12, 16 and 19 millimeters diameter shall be permitted. In machinery spaces and exterior decks, nozzles shall ensure the highest possible discharge from two jets, with a pressure at any fire connection not less than that specified in regulation 1, from the stationary pump of lower capacity.

DESIGN OF THE BILGE AND FIRE PROTECTION SYSTEM OF THE RAD II Taking into account the confined space of the engine room, it is conceivable that the same pump can serve to systems, bilge and fire. To do this, a three-way valve must be installed, which in one position connects the suction of the pump to the water main of bilge and in the other connect the suction of the pump to the water boxes, see figure 2. On the side of the discharge of the pump, in a similar manner, the broadside valve will open when bilge or FPS valves when require it. The bilge system consists of a suction branch located amidships of each compartment, in figure 2 the branch of the storeroom is identified with an illustrative purpose. Each branch is connected to the main water bilge, which is connected to the suction of the pump. The service pump is electrically operated. For emergency cases, the manual pump is coupled to the system. The pumps have a broadside discharge to the sea and a connection that discharge in port oily waters that cannot be discharged into the sea. Table 2 shows the diameters of the main water and the bilge branches resulting from the RCB rules. Table 2. Diameters of bilge system Component Water main of bilge Branch of rudder room Branch of engine room Room branch Branch of storeroom Branch of bow room

Length (m) 1,50 2,40 3,48 2,90 4,00 2,40

d0 calculated(mm) 42 33 35 34 36 33

d0 selected (mm) 40 40 40 40 40 40

¨Ordinario¨ Ejemplar:

Engine room Cuarto de máquinas

Rudder room Cuarto de timones

Room Camarote

Storeroom Pañol

Bow room Compartimento de proa

UpSalida to deck a cubiert a

2"

2"

SisCooling t ema de enfriamient system o

2"

Branch of del storeroom Ramal de achique pañol

1 12 "

0

1

2

1 12 "

3

10

1 12 "

1 12 "

18

19

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21

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25

26

27

28

29

1 12 " 1 12 "

2"

2"

1

1

2

"

1

1

2

"

2"

1"

4

6

7

8

9

1

1

2

"

11

12

13

14

15

17

16

1 12 "

Firma y fecha

No inventario Sustituye a: Firma y fecha

inventario O.T.

5

Des cargadischarge por la banda Broadside

Descarga de sustancias oleaginosas Discharge oily waters to port

Bomba Pump

Unión flexible Flexible union

Válvula de bola Ball valve

Angledevalve Vávula globo de ángulo

Bocas incendio Fire de cabinet equipadas

Non return valve Válvula de no ret or no

Bomba manual Manual pump valve Válvula valve de globo Globe

3-way Válvula valve de t r es vías

Safelydevalve Válvula s eguridad

Main water bilge Magistral de achique

Strainer Filt ro

Caja de agua Water box

Caja de fango Mud box

Suction grid Rejilla

Figure 2. Principle diagram of BS y FPS of the tug RAD II

CID NAV

CENTRODEINVESTIGACIONYDESARROLLONAVAL

ORDENCARLOSJ.FINLAY

Etapas de elaboración Mod. Cant Dib. Proy. Rev. Cont.Tec. Cont.Nor.

No notif. Molina Molina Febles Cesar Cesar

Firma

Fecha

Masa

ESQUEMA DE PRINCIPIO

Escala Hoja No

-

1

Cant. hojas

3

On the other hand, the FPS suctions sea water from the water boxes of the ship. This time the pump takes the water from these boxes to two fire cabinets (FC), in order to guarantee two jets of water to each space of the ship. The FC consists of a cabinet carrying a hose, a hose reel, a nozzle, and a shut-off valve (see Figure 3).

Figure 3. Fire cabinets.

The ship is equipped with two FC, one with a 25 mm rigid hose and a 10 mm nozzle is installed in the engine room and another with a 45 mm flat hose and a 10 mm nozzle on deck. The system must also have a pressure relief valve as a safety element. This is because the FPSs do not operate at a fixed flow rate, and in cases where the fire extinguishers are closed, the pressure relief valve will prevent the pump operates with overpressure. According to the RCB rules, the bilge pump must operate with a flow rate that guarantees at least 2 m/s in the water main. The flow rate that guarantees this velocity is 9 m3/h. On the other hand, the FPS must guarantee flow and pressure criteria. At the fire connection is required at least 0.2 MPa ≈ 20 m, while the pump, according to equation (3), must operate at least with the resulting flow of 12 m3 / h. As it´s appreciated, the pump will have an operating point for each system. To ensure that both systems operate according to the rules, an EPANET model is developed to simulate its behavior. For this, first all elements of the system must be selected and its hydrodynamic characteristics determined. The selected pump is ITUR, series AU-1,5 / 10 117 modified at 3600 rpm. The flow curves vs pressure head (Q vs H) and flow rate vs net positive suction head (Q vs NPSH) for this rotational velocity (figure 4) were determined by the affinity laws of centrifugal pumps. As usual, the accessories (valves, elbows, filters, mud boxes, among others) are introduced to the model by coefficients that relate the head losses to the velocity head for each accessory, denoted by Kacc. On the other hand, the elements that constitute emitters, as in this case, the fire nozzles and the free discharge to broadside, are simulated in EPANET by flow coefficients (K).

6,0

28

A

26

B

5,5

Head (meters)

NPSH (meters)

24 22 20 18

16

5,0 4,5 4,0 3,5

14

3,0

12 0

5

10

15 20 25 Flow rate (m3/h)

30

35

7

9

11

13 15 17 3 Flow rate (m /h)

19

21

23

Figure 4. (A) Pressure head vs. flow rate and (B) NPSH vs. flow rate of the ITUR pump. K relate the pressure that arrives to the emitter with the discharge flow, see equation (5). Therefore, the discharge rate depends to pressure that reaches the emitter. It can be concluded that in these systems the inflow in and outflow are unknowns, constituting variables to determine. To solve a system with the demands as additional unknowns is possible by the equations that contribute the emitting elements, where the flow and the pressure are related by the K. 𝑄 =𝐾×√

𝑃 𝛾

(5)

Where: K: flow coefficient in m3/s/ m0.5;Q: discharge flow rate, in m3/s; P: pressure that reach the emitter in N/m2; γ: specific gravity in N/m3 These systems are known as pressure driven models (Elhay et al., 2015); (Todini 2003). EPANET has been widely used in such models, Cabrera and Alomá (2015) developed a model in EPANET with multiple scenarios with tens of sprinklers working in the FPS of oil industry. The standards EN 671-1 (2001) and EN 671-2 (2001) are directed to the construction of the fire nozzles. These norms regulate the flow rate that must exist for different pressures in the nozzles, i.e. it establishes the flow coefficients that must be guaranty. Table 3 and table 4 show a fragment of relation of these coefficients, which relate the flow and pressure by equation (6). 𝑄 = 𝐾√10 ∗ 𝑃 (6) Where: K: in L/min/MPa0,5;Q: in L/min; P: in MPa. Table 3. Flow and minimum K in nozzle with 25 mm hose (Source UNE 671-12001) Diameter of nozzle orifice(mm) 10 12

Flow rate Q in L/min to pressure: 0,2 MPa 0,4 MPa 0,6 MPa 59 84 102 90 128 156

Coefficient K (L/min/MPa0,5) 42 64

Table 4. Flow and minimum K in nozzle with 45 mm hose (Source UNE 671-22001) Diameter of nozzle orifice(mm) 10 12 13

Flow rate Q in L/min to pressure: 0,2 MPa 0,4 MPa 0,6 MPa 78 110 135 100 140 171 120 170 208

Coefficient K (L/min/(MPa) 0,5) 55 72 85

However, the coefficient of the norm relates the pressure in MPa with the flow rate in L/min, and in equation (5) this coefficient relates the pressure in the form of a head, in meters of water column, with the flow rate in m3/s, so the standard coefficient must be converted from L/min/MPa0.5 to m3/s/ m0.5. In addition to the particularity of equation (6) of presenting 100.5 which must be multiplied with the standard coefficient, because EPANET works with the equation (5). Similarly, the broadside discharge to the BS must be simulated as an emitter. This discharge consists simply of an opened pipe to the atmosphere, so it does not have an accessory with a defined flow coefficient. However, this coefficient can be obtained from the equation of head loss in accessories, see equation (7). Due to the pressure is zero when the flow goes to the atmosphere, the pressure variation corresponds to the pressure upstream of the discharge, resulting in equation (8), in which expressing the flow rate as a function of pressure (9), the flow coefficient K is defined, see equations (10) and (11). ℎ𝑓 =

∆𝑃 𝑉2 (7) = 𝐾𝑎𝑐𝑐 𝛾 2𝑔

𝐴2 2𝑔 𝑃 𝑄=√ × √ (9) 𝐾𝑎𝑐𝑐 𝛾

∴

∴

𝑃 𝑉2 = 𝐾𝑎𝑐𝑐 𝛾 2𝑔

𝐴2 2𝑔 (10) 𝐾𝑎𝑐𝑐

𝐾=√

(8) 𝑃 𝛾

∴ 𝑄 =𝐾×√

(11)

Where: g: gravity acceleration in m/s2; A: section area in m2; Kacc=1 (for atmospheric discharge).

RESULTS Figure 5A shows the results of the simulation of FPS discharging by nozzles of 10 mm. Note that despite that pressures are greater than 20 m, the flow rate in the water main (8.31 m3/h) is lower than that required by the RCB (12 m3/h). Therefore, the following modifications are made: (i) to modify the diameter of the water main to 50 mm, (ii) to modify the diameter of pipes connected to the suction and discharge of the pump to 50 mm, (iii) To change diameter of pipe connected to FC at the engine room to 50 mm; (iv) Change the nozzle diameter to 12 mm and 13 mm in the engine room and deck respectively. The new system results as shown in Figure 5B. This time, the requirements for pressure (21.78 m and 20.06 m) and flow in (12.38 m3 / h) are reached. In BS, the bilge of each independent compartment is simulated, resulting in 5 sceneries, one for each compartment. Figure 6 shows the simulation of the bow compartment bilge, which corresponds to the most critical branch due to it has greater resistance to flow. See that it satisfies its requirement of minimum velocity in the water main of 2 m/s reaching a velocity of 2.4 m/s. However, the pump suction pressure indicates, without analyzing the NPSH, that cavitation occurs in the pump, since the value is even below to 0 in absolute pressure. This pressure, although it is impossible in reality, is the one that solves the system, and this is because the system has most of its design in the suction of the pump, whereas in the discharge there is practically no resistance, which causes an unacceptable hydraulic gradient.

Día 1, 12:00 AM

Caudal Flow rate

Presión Pressure

4.00

25.00

Nozzle 10 mm Boquilla 10 mm Hose 45 45 mm Manguera mm

21.23 4.75

Flow rate Caudal

Pressure Presión

4.00

25.00

8.00

50.00

12.00

75.00

Manguera mm Hose 45 45 mm

8.00

50.00

12.00

75.00

16.00

100.00

16.00

100.00

m

M3H

m

M3H

0.00 0.00 0.00

3.75

3.75 -0.43

-0.40

Shut-off valve Boca

21.42

-0.46

0.00

-3.75

0.00 0.00

5.59

5.59 -0.46

-0.40

Boquilla 13 mm Nozzle 13 mm

Boca Shut-off valve

0.00

-0.48

-5.59

0.00 0.00

-0.08

-0.40

0.00

-3.75 -0.49

-0.93

4.56 -0.44

0.00

0.00

0.00

23.91

8.31

8.31

Shut-off valve Boca

20.31

3.56

-1.28 8.31

23.96

libre Broadside Descarga discharge

0.00

6.79

6.79 -0.48

0.00

0.00

12.38

-0.96

-0.40

0.00 0.00

0.00

12.38

-1.22 0.00

22.77

-12.38

0.00

-0.59 22.74

0.00

0.00

12.38

12.38 -1.26 12.38

Shut-off valve Boca

19.45

0.00

0.00

0.00-0.40

5.29

22.77

0.00

0.00

Manguera mm Hose 2525 mm

B Broadside Descarga discharge libre

Figure 5. Simulation results of FPS: (A) FPS deficient, (B) FPS modified (point as decimal separator)

21.96 5.29

21.78

0.00

0.00

0.00

-0.40 0.00

23.11

Boquilla12 12 mm mm Nozzle

0.00

0.00

A

-0.40

3.56

21.41

Manguera 25mm mm Hose 25

0.00 -0.170.00 0.00 0.00 -0.40

6.79

23.96

7.09 0.00

-0.40 0.00

0.00

0.00

-0.60

0.00

-0.49 -8.31

Boquilla mm Nozzle 1010mm

-0.57

-0.14

-5.59

-0.40

8.31

-1.23 0.00

4.56

0.00

-0.40

0.00

-5.59 0.00 -0.40

0.00 8.31

4.56

0.00

-0.54

4.75 0.00

-0.40 0.00 0.00

20.06

0.00

-0.06

-3.75

7.09

-0.53

0.00 -0.46

19.64

0.00

0.00

0.00

0.00

0.00

0.00

Día 1, 12:00 AM

Boquilla 13 mm Nozzle 13 mm Velocity Velocidad

Pressure Presión

0.01

25.00

0.10

50.00

1.00

75.00

2.00

100.00

m/s

m

0.00 0.00 0.00

0.00

-0.400.00

Hose 4545mm Manguera mm shut-off valve Boca

0.00 0.00

0.00

-0.40

-0.40

0.00 0.00 -0.40

0.00

0.00

-0.40

0.00

0.00

0.00 0.00

-0.40

0.00

0.00 -0.40

0.00

0.00 -0.40

-0.40

0.00

0.00

-12.88

-0.40 0.00

0.00

-12.93

2.44

3.81

-12.88

2.44 0.00 -13.17 0.00

8.88

2.44

0.00

-0.40 0.00

8.81

3.24

2.44

Boquilla Nozzle12 12mm mm 0.00

Boca shut-off valve 0.00

0.00

0.00

0.00

0.00

0.00

0.00 0.00

-12.88 0.00

0.00

-13.41 0.00

8.88

0.00 1.79

Manguera mm Hose 2525 mm

Broadside discharge Descarga libre

0.00

3.81

0.00

1.79

3.81

0.00

0.74

1.79

Figure 6. Bilge simulation results of bow room (point as decimal separator)

-5.63

3.81

0.00

In the simulation of the remaining compartments the available NPSH (NPSHa) is below the required NPSH (NPSHr), therefore the following modifications are made, (i) to modify the diameter of the bow branch to 65 mm and the rest the branches to 50 mm of diameter (ii) to place in the bilge discharge a gate valve of 40 mm in diameter. Despite the diameter increases, the NPSHd continues to be lower than NPSHr for all scenarios. Therefore, a gate valve is placed in the discharge of the pump in order to regulate the flow. This valve is regulated to a partial opening of 25% for a Kacc = 20. The results of the NPSHd after these modifications are shown in Figure 7, see this time the NPSHd is higher than NPSHr with more than one meter of reserve. Note in figure 7 that the reason the bow branch is modify to 65 mm is because of the low reserve between the NPSHd and NPSHr for a diameter of 50 mm (point with a square marker). 8 7

6,34 Engine room

5,89 Storeroom

7,74 Bow room

NPSH (mca)

6 5 4

5,06 Bow room with 50 mm water main diameter

3

2

6,03 Room and rudder room NPSHr

1 0 16,7

NPSHd 16,8

16,9

17,0

17,1

17,2

17,3

17,4

17,5

17,6

17,7

17,8

17,9

18,0

Caudal (m3/h)

Figure 7. NPSH for each bilge scenario. Figure 8 shows the simulation of the bow branch after the modifications described. Likewise, the minimum velocity in the bilge water main (2 m/s) is reached for each scenario, as shown in Table 5. Table 5. Flow rate and velocity in the bilge water main for each scenario Parameter Flow rate (m3/h) Velocity (m/s)

Rudder room 17,16 2,43

Engine room 17,29 2,45

Room 17,16 2,43

Store room 17,10 2,42

Bow room 17,88 2,53

Finally, the system has a pump of 30 kg, 53m of pipes and 54 accessories that correspond to a weight of 230 kg, for a total of 260 kg. The selection of the equipment was governed by the simulation, which allows complying with the rules, compromising weights and dimensions to the smallest extent possible.

Día 1, 12:00 AM

Boquilla Nozzle 13 13 mmmm Velocidad

Presión

0.01

25.00

0.10

50.00

1.00

75.00

2.00

100.00

m/s

m

0.00 0.00 0.00

0.00

0.00 -0.40

Hose 4545 mm mm Manguera shut-off valve Boca

0.00 0.00

0.00

-0.40 0.00

-0.40

0.00 -0.40

0.00

0.00

-0.40

0.00

0.00

0.00 0.00

-0.40

0.00

-0.40

0.00

0.00

0.00

2.53

-1.84

0.00

-1.79

shut-off valve Boca 0.00

-0.40 0.00

0.00

19.70

-0.40 0.00

19.63

0.00

2.53

0.00

0.00

0.00

2.53

Nozzle12 12mm mm Boquilla

0.00

1.50

-1.79

2.53

-2.10 0.00 -0.40

-0.40

0.00

0.00

0.00

0.00

0.00 0.00

-1.79 0.00

0.00

-2.35

0.00

19.70

0.00 3.95

0.00 1.92

mm Manguera Hose 2525 mm

Broadside discharge libre Descarga

6.84

0.00

1.92

3.95

0.00

0.80

1.92

Figure 8. Bilge simulation results of the bow room after modifications (point as decimal separator)

-1.10

1.50

0.00

CONCLUSIONS  This work demonstrates that the integrated simulation to the design process of ship piping systems, allows to configure the systems so that the variables of flow are within the recommended and regulatory ranges.  On the other hand, it shows how the computer simulation makes possible the recreation of different scenarios of the system; as well as the analysis of variants and the characteristic gradual design of the ship piping systems.  It is evident that the possibility of simulating most of the system elements, it allows to evaluate the feasibility of each one and avoids the selection of oversized or erroneous components. Making possible the optimization of weights and costs of the systems. REFERENCES Asmara A. (2013). “Pipe routing framework for detailed ship desing”, Ed. Association for Studies and Student Interest in Delft (VSSD), ISBN: 97890-6562-326-3, Delft. Cabrera E. y Alomá A. (2015). “Sistemas contra incendios para industria petrolera. Parte 3. Modelo detallado de red”, Ingeniería Hidráulica y Ambiental, Vol.36, No. 3, pp. 33-47, ISSN 1815-591X, CIH, Universidad Tecnológica de La Habana José Antonio Echeverría (Cujae), La Habana. Cassee H. J. (1992). “Piping systems”, in Marine engineering, pp. 782-845,ISBN: 9780939773107, Ed. Society of Naval Architects and Marine Engineers, Jersey. Elhay S.; Piller O.; Deuerlein J. and Simpson A. R. (2015). “A robust, rapidly convergent method that solves the water distribution equations for pressure-dependent models”, Journal of Water Resources Planning and Management, Vol.142, No. 2, pp. 1-11, ISSN: 1943-5452, American Society of Civil Engineers (ASCE), Adelaide. EN 671-1. (2001). “Instalaciones fijas de sistemas contraincendios. Sistemas equipados con mangueras. Parte 1: Bocas de incendio equipadas con mangueras semirrígidas”, Asociación Española de Normalización y Certificación, España. EN 671-2. (2001). “Instalaciones fijas de sistemas contraincendios. Sistemas equipados con mangueras. Parte 2: Bocas de incendio equipadas con mangueras planas”, Asociación Española de Normalización y Certificación, España. Rossman L. A. (2001). “EPANET manual de usuario”. U.S. Environmental Protection Agency, Cincinnati, Ohio. RCB (2006). “Reglas para la clasificación y la construcción de los buques marítimos”.Sociedad Clasificadora, Ministerio de Transporte (MITRANS),La Habana. Todini E. (2003). “A more realistic approach to the extended period simulation of water distribution networks” in Advances in water supply management, pp. 173-183, ISBN: 978-905809-608-1, Ed. Taylor & Francis, London. Walski T. M. (2006). “A history of water distribution”. Journal-American Water Works Association, Vol. 98, No. 3, pp. 110-121, ISSN: 0003-150X, American Water Works Association, Denver, USA.