Comparative Structural Analysis of Hydrodynamic Interaction of

Full-Submerged Tandem Archimedes Screws of Rotary-Screw

Propulsion Units of Snow and Swamp-Going Amphibious Vehicles

with the Water Area in Running and Mooring Modes

Svetlana Karaseva

, Aleksey Papunin

, Vladimir Belyakov

, Vladimir Makarov

Dmitry Malahov

and Anton Klyushkin

Nizhny Novgorod State Technical University n.a. R.E. Alekseev, Minin Str., 24, Nizhny Novgorod, Russian Federation

Moscow Automobile and Road Construction State Technical University,

Leningradsky prospect, 64, Moscow, Russian Federation

malahow_dm@mail.ru, aak-nntu@yandex.ru

Keywords: Rotary-Screw Propulsion Unit, Snow and Swamp-Going Vehicle, Thrust, Torque, Efficiency,

Hydrodynamics.

Abstract: The paper deals with the issues of analysis of thrust and torque of structural elements of rotary-screw

propulsion units of snow and swamp-going amphibious vehicles of tandem design when operating on water.

For a wide range of propulsors with three variants of the helix angle, the contribution of various elements of

Archimedes screws to the overall efficiency of the propulsor is analyzed. A comparative analysis of the

hydrodynamics of rotary-screw propulsion units in running and mooring modes is given.

1 INTRODUCTION

Nowadays, there is a clear tendency to explore the

regions of the Arctic, Siberia and the Far North in

connection with the active extension of the sphere of

subsoil use and the development of gas and oil fields.

In these territories, there are mainly such supporting

bases as snow, ice, water, sludge, broken ice in the

water, as well as swamp, silt, etc. Rotary screw

propulsion units are the best suited for such operating

conditions due to the low pressure they exert on the

support base by virtue of the specifics of the design.

The features and parameters of the motion of

rotary-screw propulsors on the water are extremely

little known, and therefore it is important to study the

hydrodynamics of these propulsion units in order to

ensure an optimal ratio of overwater and overland

characteristics when designing them.

Earlier, the authors carried out studies of the

hydrodynamics of single rotary-screw propulsion

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units, as a result of which dependencies of a similar

nature were obtained, as given in this work. The

results of the structural analysis of the hydrodynamic

interaction of such Archimedes screws with the water

area are given in the paper (Karaseva, 2022).

2 DESCRIPTION OF COMPUTER

SIMULATION

To solve the problems, computer simulation methods

were used at constant values of the flow velocity v =

4 m/s in the running mode and 0 m/s in the mooring

mode; the values of the rate speed of propulsor varied

in the range n = 200 ... 600 rpm.

Figure 1 shows the image of the three-start models

of tandem Archimedes screw propulsors used. The

geometric characteristics of all three models, with the

exception of the angles of inclination of the helix, are

386

Karaseva, S., Papunin, A., Belyakov, V., Makarov, V., Malahov, D. and Klyushkin, A.

Comparative Structural Analysis of Hydrodynamic Interaction of Full-Submerged Tandem Archimedes Screws of Rotary-Screw Propulsion Units of Snow and Swamp-Going Amphibious

Vehicles with the Water Area in Running and Mooring Modes.

DOI: 10.5220/0011992300003479

In Proceedings of the 9th International Conference on Vehicle Technology and Intelligent Transport Systems (VEHITS 2023), pages 386-393

ISBN: 978-989-758-652-1; ISSN: 2184-495X

 2023 by SCITEPRESS – Science and Technology Publications, Lda. Under CC license (CC BY-NC-ND 4.0)

identical and are the most typical for rotary-screw

propulsion units of snow and swamp-going vehicles

(Kulyashov, 1993; Danilov, 2011; Kolotilin, 2015;

Shapkin, 2017). The values of the helix angles are,

respectively, 24, 30 and 39 degrees: smaller angles of

inclination correspond to typical values for traction

vehicles, large ones – for transport vehicles.

As a result of computer simulation of the

hydrodynamics of the models, a large amount of data

was obtained. As a graphical representation of the

simulation results, some of the visualization patterns

shown in Figure 2 can be considered.

The analysis of these patterns confirms the

complexity of the hydrodynamics of the interaction of

tandem Archimedes screws with the water area. For

the possibility of structural analysis, the entire

propulsor was divided into logical elements, namely:

front cowl, rear cowl, input and output helixes

divided into three elements each, as well as

cylindrical parts of the helixes of the fore and aft

Archimedes screws in the amount of 8 elements – 4

elements per Archimedes screw (Figure 1). Averaged

values of thrust in the longitudinal direction and

torque with respect to the axis of rotation of the

propulsor were monitored on each of these elements.

In addition, the base cylinders of both Archimedes

screws themselves were also divided into 4 elements

each; however, these elements practically do not

participate in the creation of thrust or resistance,

therefore they are not shown in the diagrams.

It is also worth noting separately the fact that the

distribution of loads is non-uniform for the remaining

elements of the screw propulsion unit.

Figure 1: Images of rotary-screw propulsor models used for computer simulation.

Running mode (v = 4 m/sec) Mooring mode

Figure 2: Examples of patterns of interaction between Archimedes screw and water area (helix angle 30°, n = 400 rpm).

Comparative Structural Analysis of Hydrodynamic Interaction of Full-Submerged Tandem Archimedes Screws of Rotary-Screw Propulsion

Units of Snow and Swamp-Going Amphibious Vehicles with the Water Area in Running and Mooring Modes

387

Figure 3: Distribution of specific thrust across the elements of the rotary-screw propulsor in running and mooring modes.

3 ANALYSIS OF THE ELEMENT-

BY-ELEMENT DISTRIBUTION

OF SPECIFIC THRUST AND

SPECIFIC TORQUE

Figures 3 and 4 show the specific thrust and specific

torque curves on the main elements for three

propulsor models in running and mooring modes. For

the running mode, the curves are presented in the

traditional dimensionless form, depending on the

advance ratio. For the mooring mode, in which the

speed of the frontal incoming water flow is zero and

the advance ratio, respectively, is also zero, a slightly

different principle is used, namely, dependence on the

number of revolutions of the propulsor.

VEHITS 2023 - 9th International Conference on Vehicle Technology and Intelligent Transport Systems

388

Figure 4: Distribution of the specific moment across the elements of the rotary-screw propulsor in running and mooring

modes.

On the diagrams, Т

is the thrust of the propulsor

certain element, Q

is the corresponding torque, T is

the total thrust of the mover, Q is the total input

moment, J is the advance ratio equal to

𝐽

𝑣



𝑛∙𝐷

(1)

where V

is the water flow velocity (m/sec), n is

the speed of rotation of the propulsor (rpm), D is the

diameter of the Archimedes screw (m) (Basin, 1977).

As can be seen from the diagrams, the elements

of the rotary-screw propulsor can create both thrust

and resistance, which is manifested in positive and

negative values on the diagrams, respectively.

Comparative Structural Analysis of Hydrodynamic Interaction of Full-Submerged Tandem Archimedes Screws of Rotary-Screw Propulsion

Units of Snow and Swamp-Going Amphibious Vehicles with the Water Area in Running and Mooring Modes

389

Figure 5: Distribution of thrust along the length of helixes of the Archimedes screws in the running and mooring mode.

When analyzing the data on the parameters of

movement in the running mode, it can be seen that the

greatest contribution to the creation of thrust is made

by the helixes of the aft Archimedes screw located on

the base cylinder (Figure 3). In addition, the input

helixes are also quite actively involved in this

process, although for transport vehicles with a

propulsor with the helix angle approaching to the

upper limit of the range of typical values the

efficiency of the input part of the helixes decreases a

bit, and the efficiency of the cylindrical part

increases. Output helixes are practically not involved

in the creation of thrust. The greatest contribution to

the creation of resistance is made by the rear cowl, its

resistance is least for vehicles with average values of

helix angles. In addition, the resistance is also created

by the front cowl, but it is a bit smaller and not for all

models: for traction machines with small helix angles

the resistance of the front cowl is greater, while for

transport vehicles it is practically zero.

VEHITS 2023 - 9th International Conference on Vehicle Technology and Intelligent Transport Systems

390

Figure 6: Distribution of torque along the length of helixes of the Archimedes screws in the running and mooring mode.

The behaviour of the cylindrical part of the

helixes of the fore Archimedes screw is most

interesting, since at small helix angles they create

resistance, at medium – they participate in thrust

creation on a par with the input helixes, and at large –

they create both resistance and thrust depending on

the value of the advance ratio.

In the mooring mode, an almost identical pattern

of the nature of the curves is observed, with the

exception of the behaviour of the helix cylindrical

part of the fore Archimedes screw, which create

resistance for all three models, and their contribution

to this process is the greatest in comparison with other

elements.

When analyzing the distribution of specific torque

across the propulsor elements in the running mode, it

is possible to note the characteristic similarity of most

curves with the thrust distribution curves (Figure 4).

The cylindrical part of the helixes of the aft

Archimedes screw contributes the most to the

creation of the turning torque as well as to the creation

of thrust; the input helixes also participate in this

Comparative Structural Analysis of Hydrodynamic Interaction of Full-Submerged Tandem Archimedes Screws of Rotary-Screw Propulsion

Units of Snow and Swamp-Going Amphibious Vehicles with the Water Area in Running and Mooring Modes

391

process. The rear cowl creates neither turning nor

braking torque, its participation is minimal. The

greatest braking torque is created by the front cowl;

the output part of the helixes also creates a slight

braking at small and medium angles of inclination of

the helix, however, with an increase of this angle, the

value of the braking torque drops to zero at 39

degrees.

One of the main differences from the formation of

thrust is the fact that the behaviour of the cylindrical

part of the helixes of the fore Archimedes screw in

this case is practically unchanged for all three models

studied. The values of the specific moment on these

elements are 2…3 times more than those on the input

helixes.

When comparing the behaviour of the propulsor

elements and their participation in the formation of

the torque in the mooring mode it can be concluded

that the overall picture, as in the case with thrust, is

almost identical to the running mode.

4 ANALYSIS OF THE

DISTRIBUTION OF THRUST

AND TORQUE ALONG THE

LENGTH OF THE HELIXES

Of particular interest is the distribution of thrust and

torque along the length of the helixes of the rotary-

screw propulsor shown in Figures 5 and 6. For

graphical representation, the helixes are divided into

10 elements, numbered in order from fore to aft

(Figure 1). So, the value "0" corresponds to the input

element of the helixes, and "9" corresponds to the

output one. These values on the diagrams are

postponed along the abscissa axis.

When analyzing the patterns of thrust distribution

in the running and mooring modes, we can note their

fundamental similarity for all models in both modes.

The nature of the curves is exactly the same for the

certain elements of the helixes. The front part of the

aft Archimedes screw (element "5") takes the greatest

part in creating thrust, which is presumably explained

by the work in the flow twisted in the opposite

direction by the fore Archimedes screw. In addition,

a significant contribution is made by the front part of

the rotary-screw propulsor, namely, the input part of

the helixes and the front part of the fore Archimedes

screw (elements "0" and "1"). A small thrust is

created by the middle parts of the Archimedes screws.

The greatest resistance is created by the rear part of

the fore Archimedes screw, although the rear part of

the aft Archimedes screw together with the rear cowl

makes a small contribution to this process. The

patterns are identical for both running and mooring

modes.

The torque distribution also has a similar

character (Figure 6). As it can be seen, the greatest

contribution to the creation of the torque is also made

by the front part of the propulsor helixes. The middle

and rear parts of the fore Archimedes screw in the

running mode create very little torque, but in the

mooring mode they practically do not participate in

this process, as well as the rear part of the aft

Archimedes screw in all modes.

An interesting thing is the transition of part of the

elements to the "turbine mode", that is to the

operating mode when the element creates a negative

braking torque. To simplify the perception of such a

mode, a picture can be conditionally imagined when

the water flow is not twisted by the propulsor, but vice

versa. A low turbine mode is observed on the output

part of the helixes, but a much larger braking torque

is created by the front and middle part of the aft

Archimedes screw or, to be more precise, almost its

entire cylindrical part. This can be explained by

working in a stream of water twisted by the front

screw, and, characteristically, this behaviour is

manifested for all the considered helix angles in all

modes, which allows us to assume quite confidently

that such a picture will be typical for Archimedes

screws with other parameters.

5 CONCLUSIONS

Based on the analysis of the above patterns, it can be

concluded that the obtained dependences illustrate

stable trends in the behaviour of specific elements of

tandem rotary-screw propulsors of snow and swamp-

going vehicles with typical parameters, regardless of

the speed and number of revolutions, including

mooring mode. Taking into account the stability and

generality of the nature of the thrust and torque

curves, it is safe to assume that the data obtained can

be used to study the hydrodynamic interaction of

tandem rotary-screw propulsion units with the water

area also with other parameters of the geometry of the

Archimedes screws and the working area.

ACKNOWLEDGEMENTS

The results of the given study have been obtained

with financial support of the grants of the President of

the Russian Federation № MK-336.2022.4.

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392

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Comparative Structural Analysis of Hydrodynamic Interaction of Full-Submerged Tandem Archimedes Screws of Rotary-Screw Propulsion

Units of Snow and Swamp-Going Amphibious Vehicles with the Water Area in Running and Mooring Modes

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