Design Analysis and Optimal Matching of a Controllable Pitch Propeller to the Hull and Diesel Engine of a CODOG System

Abstract

The optimal matching of a propeller to the hull and the diesel engine of the combine diesel or gas (CODOG) system is a critical design analysis in ship building. In this research work, a controllable Pitch Propeller (CPP) was considered whereby the pitch was varied, but only the extreme pitch set the limit of operation and matching was done with the extreme pitch condition. It considers the performance analysis of the propeller, the hull and the engine both in design and off design conditions. Without propulsion a vessel built cannot move and so choosing the right propeller to match the hull and engine is very vital. The various processes involved in the matching of the propeller to the diesel engine and hull of the vessel are considered, in order to achieve optimal performance of the vessel. A Java program (prop-matching) was developed to facilitate the matching process. The graphs obtained are used to determine the matching point at corresponding speed and power. The thrust and torque developed under different conditions as well as their significance, considering the fact that the propeller is a CPP. The engine response in transient conditions in reaction to the turbo charger was considered, the matching graph of the turbo charger compressor was discussed, and the calculated mass flow rate with various engine speeds and boost pressure were also discussed. This program was further used in matching the propeller to the hull and diesel or gas engines of a F90 frigate. The corresponding propeller rpm and engine power with pitch ratios from the program were similar to those from the design of the frigates. The various thrust and torque coefficients and open water efficiency all correspond to the simulated results of those of the naval frigate.

Design Analysis of a Lightweight Solar Powered System for Recreational Marine Craft

“…The wetted keel length to beam ratio for a hull with Deadrise (β) is given by Equation (7). The expressions for the mean hull speed, trim and total resistance are given by Equations (8), (9) and 10 The hydrodynamic moment factor ()m Δ is a necessary correction for the wetted length ratio which is absent in Savitsky model. Details about CAHI method are presented [19], however, for dimensional total resistance variables such as: the speed V, displacement Δ, chine beam b, Deadrise angle β, longitudinal center of gravity LCG, mean wetted length ratio λ, and the trim τ are identified…”

Influence of EEDI (Energy Efficiency Design Index) on Ship–Engine–Propeller Matching

“…• reference line value (14) where X is the reduction factor specified in Table 2 for the required EEDI compared to the EEDI reference line. 1 '*' is the reduction factor linearly interpolated between the two values dependent upon vessel size.…”

“…where a, b and c are the parameters given in Table 3. For a new-built ship, the attained EEDI is calculated by Equation (13), and its required EEDI is recommended by Equations (14) and (15). Only meeting the requirement that the attained ≤EEDI required EEDI, can this ship get a EEDI license.…”

“…Besides the matching for conventional power configuration, there are some researches on the new types of ship propulsion such as hybrid propulsion. Ogar et al analyzed performance of controllable pitch propeller (CPP), ship hull and engine in both design and off-design conditions to design a control strategy for the optimal matching of a combined diesel or gas turbine (CODOG) system [14]. Sasaki et al introduced a design method for hybrid CRP (contra rotating propeller) podded drive systems to achieve the best index for transportation efficiency and avoid poor navigation operations [15].…”

Investigating the Performance of a Ship by Matching the Stern Hull Form to Propeller and Engine Power

“…Lin et al [3] proposed a process to design ship-engine-propeller simultaneous matching where the ship-propeller subsystem and the enginepropeller subsystem in which relationships between rotational speed of the propeller and advancing speed that were expressed N-V curves. Ogar et al [4] proposed the design analysis to use for optimal matching of controllable pitch propeller to the hull and diesel engine. In order to make the wake field more uniform, the stern frame from above the shaft line was shifted to the stem and the stern bulb sectional area was increased and the gravity center of the area was made lower.…”