# A Review of Progress and Hydrodynamic Design of Integrated Motor Pump-Jet Propulsion
## 3 IMP Bearing and Hydrodynamic Design
### Hydrodynamic Design
#### 3.2.1 Hydrodynamic Performance
\begin{table}
\begin{tabular}{p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt}} \hline \hline
**Parameter** & **Year** & **Reference** & **Model** & **Method/Experimental Method** & **Findings** \\ \hline
**Propeller pitch ratio** & 2003 & [22] & RDT & The interaction velocity-field approach was used in this lifting-surface panel code. & 1. & The torque provided by the motor reduced as the rpm rose, whereas the torque required by the propeller rose. & The propeller’s torque requirements rose as the pitch ratio increased, although this was limited. \\ \hline
**Shape and size of the rim** & 2015 & [46] & Ka-series thruster & Reynolds-averaged using varied-length rims to solve the Navier-Stokes equation. & 1. & A lengthy rim raised the friction torque slightly and caused the local flow to have a circumferential velocity. & A lengthy rim raised the friction torque slightly and caused the local flow to have a circumferential velocity. & A lengthy rim raised the friction torque slightly and caused the local flow to have a circumferential velocity. & A lengthy rim raised the friction torque slightly and caused the local flow to have a circumferential velocity. & A lengthy rim raised the friction torque slightly and caused the local flow to have a circumferential velocity. & A thin blade outperformed a thick one in terms of efficiency. \\ \hline
**Shape and size of the hub** & 2015 & [47] & Open-water performance of hub-type and hub-type and hubless RDTs (rim-driven thrusters), the propeller Ka4-70 propeller Ka4-70 and duct JD7704 and duct JD7704 & Contrastive analysis, with Reynolds-averaged Reynolds-averaged Navier-Stokes (RANS) & 2. & The efficiency gap widened as the hub diameter and advance coefficient grew. The hubless RDT efficiency was 2.2 percent greater than the hub-type RDT for a hub ratio of 0.25 and an advance coefficient of 0.7 (the design point). & The efficiency gap widened as the hub diameter and advance coefficient grew. The hubless RDT efficiency was 2.2 percent greater than the hub-type RDT for a hub ratio of 0.25 and an advance coefficient of 0.7 (the design point). & The disappearance of the hub resulted in increased thrust, torque, and a smaller thrust ratio. \\ \hline
**Shape and size of the duct** & 2001 & [48] & The MARIN Ka4-70 in 37A duct & Comparison between a symmetrical propeller and a standard asymmetric ducted propeller & A symmetrical propeller provided less thrust per unit power, because it had a lower KT value and a greater KQ value. \\ \hline
**Shape and size of the duct** & 2001 & [20] & S2037, S2637, F2637 & Contrastive analysis & 1. & The S2037 produced somewhat higher thrust than the other two profiles in a symmetrical duct layout, with the F2637 being the worst. & The S2037 produced somewhat higher thrust than the other two profiles in a symmetrical duct layout, with the F2637 being the worst. & The S2037 produced somewhat higher thrust than the other two worst. & The S2037 produced somewhat higher thrust than the other two profiles in a symmetrical duct layout, with the F2637 being the worst. & The S2037 being the worst. & The S2037 being the worst. & A symmetrical propeller produced slightly more thrust than the symmetrical propeller, but still far less than the thrust produced by the MARIN Ka4-70 in a 37A duct. \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Summary of numerical studies on the hydrodynamic performance of IMP thrusters.