﻿ 一种系列化喷水推进装置的快速选型方法
 舰船科学技术  2024, Vol. 46 Issue (11): 92-97    DOI: 10.3404/j.issn.1672-7649.2024.11.017 PDF

1. 喷水推进技术重点实验室，上海 200011;
2. 中国船舶及海洋工程设计研究院，上海 200011

A fast model selection method for marine series waterjets
MENG Kunyu1,2, LV Ning2
1. Key Laboratory of Waterjet Propulsion, Shanghai 200011, China;
2. Marine Design and Research Institute of China, Shanghai 200011, China
Abstract: Waterjets are usually supplied in a serialized model. The waterjet supplier selects one proper model from the series products according to the ship main dimension, design speed, power system and other input parameters provided and the ship-diesel-jet matching theory to meet the requirements. This paper presents a fast model selection method for marine series waterjets. Through this method, the appropriate marine series waterjet can be quickly selected under the condition that only the ship speed and main power are known. This method is suitable for the preliminary demonstration and scheme design stage of the ship. The ship-owner or designer can use the waterjet sample and this method to achieve fast model selection. The analysis error of the selection results is small, which can meet the needs of engineering application.
Key words: waterjet     serialized     fast selection     ship-diesel-jet matching
0 引　言

1 常规方法

 $\frac{{{Q_s}}}{{{Q_m}}} = {\lambda ^3}\frac{{{n_s}}}{{{n_m}}} ，$ (1)
 $\frac{{{H_s}}}{{{H_m}}} = {\lambda ^2}{\left(\frac{{{n_s}}}{{{n_m}}} \right)^2} ，$ (2)
 $\frac{{{P_{es}}}}{{{P_{em}}}} = {\lambda ^5}{\left (\frac{{{n_s}}}{{{n_m}}}\right)^3} ，$ (3)
 $\frac{{NPS{H_{rs}}}}{{NPS{H_{rm}}}} = {\lambda ^5}{ \left (\frac{{{n_s}}}{{{n_m}}}\right)^3}。$ (4)

 ${n_s} = \frac{{3.65n\sqrt Q }}{{{H^{0.75}}}}，$ (5)
 $c = \frac{{5.62n\sqrt Q }}{{NPS{H_r}^{0.75}}} 。$ (6)

1）喷水推进系统的推力与设计工况下的船体阻力相平衡：

 $T = \rho Q({V_j}- \alpha {V_0}) = R 。$ (7)

2）主机发出功率和推进泵收到功率相平衡：

 $P = \frac{{\rho gQH}}{{{\eta _{{p}}}}} 。$ (8)

3）推进泵扬程与喷水推进系统总水力损失平衡方程为：

 $H = \frac{{(1 + {k_j})}}{{2g}}V_j^2 + \frac{{({k_1}-\beta )}}{{2g}}V_0^2 。$ (9)

 $NPS{H_a} = \frac{{{p_a} - {p_v}}}{{\rho g}} + \beta \frac{{{V_0}^2}}{{2g}} - \zeta \frac{{{V_{{\mathrm{in}}}}^2}}{{2g}}。$ (10)

 $NPS{H_a} \geqslant k{}_2 \cdot NPS{H_r} 。$ (11)

2 快速选型方法

 $NPS{H_r} = {\left (\frac{{5.62{n_s}}}{{3.65c}}\right)^{4/3}} \times H 。$ (12)

 $H = \frac{{P{\eta _p}}}{{\rho gQ}} 。$ (13)

 ${H_{NPSHr}} = {\left(\frac{{5.62{n_s}}}{{3.65c}} \right)^{4/3}} \times \frac{{P{\eta _p}}}{{\rho gQ}} 。$ (14)

 $\frac{{{P_a} - {P_v}}}{{\rho g}} + \beta \frac{{V_0^2}}{{2g}} - \zeta \frac{{V_{\text{in}}^2}}{{2g}} \geqslant {k_2} \cdot { \left (\frac{{5.62{n_s}}}{{3.65c}}\right)^{4/3}} \times \frac{{P{\eta _p}}}{{\rho gQ}} 。$ (15)

 $\begin{split} Q \geqslant &{k_2} \times { \left (\dfrac{{5.62{n_s}}}{{3.65c}}\right)^{4/3}} \times \dfrac{{P{\eta _p}}}{{\rho g{H_{NPSHa}}}}={k_2}\times\\ & { \left(\dfrac{{5.62{n_s}}}{{3.65c}}\right)^{4/3}} \times \dfrac{{P{\eta _p}}}{{{P_a} - {P_v} + \rho \beta \dfrac{{V_0^2}}{2} - \rho \zeta \dfrac{{V_{{\mathrm{in}}}^2}}{2}}}。\end{split}$ (16)

 ${D_{s{\text{min}}}} \geqslant {D_m} \cdot {\left(\frac{{{Q_s}}}{{{Q_m}}} \times {\left(\frac{{{P_m}{\rho _s}}}{{{P_s}{\rho _m}}}\right)^{1/3}} \right)^{3/4}}。$ (17)

 图 1 系列化喷水推进装置常规选型和快速选型流程对比 Fig. 1 Comparison between common process and fast process jet model selection of the series waterjets

3 影响分析

1）推进泵内扬程平衡

 图 2 某泵模型的Q-ηp和Q-c性能曲线 Fig. 2 Q-ηp and Q-c performance curves of a waterjet pump

2）船-泵相互影响系数

3）主机功率

 图 3 喷水推进效率统计图[6] Fig. 3 Waterjet propulsion efficiency statistics

4）航速汽蚀余量

 图 4 典型喷水推进船舶的航行特性曲线图 Fig. 4 Curves of navigation characteristics of typical waterjet propelled ships

5）船舶阻力

4 设计实例

 图 5 ZLA系列轴流式喷水推进装置快速选型图谱 Fig. 5 ZLA series axial-type waterjets fast model selection chart
5 结　语

1）采用本方法，已知船舶设计航速和主机功率，可实现系列化喷水推进装置的快速选型。

2） 快速选型方法忽略了推进泵内的扬程平衡计算过程，且部分船-泵相互影响系数采用通用数据，这会对选型结果造成一定影响。经分析，在设计单位能较好把握船舶阻力、主机功率等输入的条件下，针对系列化喷水推进装置的快速选型结果能满足工程应用需求；

3）快速选型结果通过实例验证。文中还绘制了系列化选型图谱，应用时可省略了计算过程，便于快速选型。

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