Purpose and main elements of the gating system. Gating systems: types, design. Press mold for casting. Good gating system

Depending on the size, configuration and material of the product being cast, the gating system in the mold can be horizontal, top, rain, siphon and tiered. Let's consider several types of gating systems used in the casting of artistic and architectural products.

Horizontal gating system (Fig. 3.47, A) with feeders located in a horizontal plane, ensures the supply of metal into the mold cavity through its connector. This gating system has all the main elements and is used in molds that are poured in a raw form with a cavity depth in the lower flask of up to 200 mm. Thin-walled openwork castings (vases, dishes, plates, brackets) with insignificant wall thickness have a complex surface. It is not possible to qualitatively fill the casting molds of such products through a gating system with a horizontally located feeder on one side of the mold cavity, since the melt in the thin section of the mold cavity quickly cools and does not fill it completely. In such cases, a horizontal gating system with a large number of feeders located along the cavity connector is used for filling (Fig. 3.47, b). To do this, a slag catcher with a triangular cross-section is cut around it in the upper half-mold, and below it, in the lower half-mold around the mold cavity, the required number of feeders is cut out. Metal poured into a mold with such a gating system enters it simultaneously in several places. At the same time, it does not have time to cool and fills well the smallest recesses and protrusions of the complex surface of the cavity.

Siphon gating system (Fig. 3.47, V) - horizontal or vertical - ensures the supply of molten metal into the mold cavity from below. Such a system eliminates the possibility of destruction of the lower surfaces of the mold cavity and splashing of metal when its jet falls to the bottom of the mold. Individual drops of metal do not fuse well with the total mass and form inclusions (kinglets) in the casting. Casting molds for figurines that have a significant height with small transverse dimensions are usually poured in a vertical position. The metal enters the cavity of such molds from below (along the riser to the bottom of the mold), and then passes through a horizontal feeder into the mold cavity and, under pressure in the riser, gradually fills it to the top.

Rice. 3.47.

Upper gating system (Fig. 3.47, G) ensures the supply of metal into the mold cavity from above. In small openwork casting molds, the riser of the upper gating system is made in the form of a slot into the mold cavity from above, which is why it is often called a slot gating system. This gating system is convenient in that it can be placed in the center of the mold cavity, from where the metal spreads evenly to all its parts. In addition, the use of a vertical gating system in thin-walled casting molds is convenient because the cross-section of the slotted riser does not exceed the thickness of the casting, so the riser easily breaks off without destroying the walls of the casting or leaving a large mark on its surface.

Tiered gating system - a vertical gating system - provides metal supply into the mold cavity at several levels of its height. The siphon gating system ensures quiet, consistent filling of the mold, but at the same time it has a significant drawback when casting thin-walled artistic castings. Metal in this form, rising from the bottom up, meeting the cold walls of the mold, cools quickly, poorly fills the upper part of the mold cavity and does not give a sharp relief to the surface of the casting. This drawback can be eliminated if you slightly change the design of the siphon gating system, providing it with additional feeders along the height of the mold. With a tiered gating system, the first portion of metal that enters the mold at the beginning of pouring, having had time to cool somewhat, is heated by a portion of hot metal that arrives at the level of the first additional feeder.

The same thing will happen when the mold is filled to the second feeder. Thus, the upper cold layer of metal in the mold is heated by portions of hot metal coming from tiered feeders. In this case, some equalization of the temperature of the metal in the mold cavity occurs, ensuring the same sharpness of the surface relief of the casting in all its parts.

In casting molds of figurines and busts with a siphon and tiered gating system, it is not possible to install a slag catcher. In such molds, the slag during pouring is held in a sprue bowl, which must have sufficient dimensions and appropriate design to ensure the floating of slag particles during pouring.

When using small sprue bowls (funnels), this is facilitated by a specially made from the core mixture and a dried filter mesh inserted into the bottom of the funnel. If the funnel has a filter mesh, the metal is inhibited in it and fills the funnel. Slag and dirt float to the surface of the metal and remain there until the pouring is completed.

Types of gating systems

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Foundry

Types of gating systems

A gating system is a set of channels and reservoirs through which liquid metal from a ladle enters the cavity of the casting mold. The gating system has a significant impact on the quality of castings; If it is incorrectly designed or calculated incorrectly, it can cause defective castings.

The main elements of the gating system are the following.

A sprue funnel or bowl is a reservoir designed to receive liquid metal from a ladle, partially retain the slag (in the bowl) and transfer the metal to the riser.

A riser is a vertical (sometimes inclined) channel of a round, oval or other cross-section, designed to transfer metal from a bowl (funnel) to other elements of the gating system (slag catcher, feeders).

Rice. 1. Gating system elements

The gate passage, called a “slag catcher” for iron castings and a manifold for non-ferrous castings, is a horizontal channel designed to retain the slag and transfer the riser metal to the feeders.

Feeders (runners) are channels designed to transfer metal directly into the mold cavity.

Rice. 2. Types of gating systems: 1 - bowl (funnel); 2 - riser; 3 - gate stroke; 4 - feeder; 5 - thrust; 6 - casting

Gating systems are divided into five main types:
1. Upper gating system (Fig. 2, a). Feeders are supplied either to the upper part of the casting, or to the profit or below the profit.
2. Lower or siphon gating system (Fig. 2, b). Feeders are brought into the lower part of the casting.
3. Side gating system (Fig. 2, c). Feeders are supplied through the mold connector.
4. Tiered (story) gating system (Fig. 2, d). Feeders are connected to the casting at several levels. A variation of the tiered gating system is the vertical slot system (Fig. 2, e).
5. Rain gating system.

The casting system is selected depending on the type of metal, the design of the casting, its position during pouring, etc.

We always strive to ensure that, while ensuring the required quality of the casting, the metal consumption for the gating system is minimal. If this condition is met, the yield of suitable casting increases (the ratio of metal consumption for casting to the total metal consumption, taking into account the gating system and profits).

The upper gating system is the simplest in design, easy to implement, and requires little metal consumption. It creates the most favorable conditions for feeding the casting, i.e. creates the temperature distribution necessary for directional crystallization - an increase in temperature from the bottom of the casting to the top.

However, the upper gating system has a significant drawback, namely, when a metal jet falls from a great height, the shape is washed out and blockages form; the metal oxidizes, spatters, and the number of non-metallic inclusions in it increases. In addition, the upper gating system does not provide slag retention. Therefore, it is used for low castings of small mass, simple configuration, with small and medium wall thickness.

The lower (siphon) gating system ensures smooth filling of the mold, eliminating the risk of washing out the walls and causing blockages. However, the lower supply of metal creates an unfavorable temperature distribution throughout the volume of the casting metal (since the hot metal comes from below) and contributes to the development of local heating and internal stresses.

The siphon gating system is difficult to manufacture and requires increased metal consumption; it is usually used for medium and heavy castings of significant height and large wall thickness.

Supplying metal through a joint is one of the most common methods of filling molds for various castings, especially castings whose symmetry plane coincides with the plane of the mold parting.

The side gating system, while reducing (compared to the top) the height of metal fall and the possibility of mold destruction, at the same time worsens the crystallization conditions and increases metal consumption. It is used for castings of small height, medium weight, large sizes; widely used in machine mold making.

The tiered gating system is used for large, heavy castings. It provides better feed to the casting than a siphon gating system. The tiers of the system must feed metal into the mold cavity sequentially, from bottom to top. The tiered gating system is the most difficult to implement and requires the greatest metal consumption. The vertical-slot gating system, which ensures smooth filling of the mold while maintaining the direction of solidification, is used for casting non-ferrous alloys.

The rain gating system is mainly used for cylindrical castings. The metal from the riser enters the ring collector, from which, through feeders located around the circumference at an equal distance from each other, it evenly fills the mold cavity located below in thin streams. The metal should not splash, since drops of metal quickly harden, oxidize and do not weld with the base metal, forming defects in castings called queens,

In addition to choosing the type of gating system, the choice of the location for supplying the feeders to the casting is of great importance. Depending on the properties of the alloy, the design of the casting (overall dimensions, wall thickness), when supplying metal, they strive to ensure either directional solidification or simultaneous uniform cooling of various parts of the casting.

For castings with thick walls, massive units, prone to the formation of shrinkage cavities, it is necessary to create conditions for directed crystallization. This is achieved not only by the appropriate location of the casting in the mold, when the more massive parts are located above the thin ones, but also by the appropriate supply of metal to the most massive parts of the casting. This supply of metal enhances the effect of directional solidification. Therefore, steel, which has high shrinkage and reduced fluidity, is brought into the thick section under the profit in order to heat the mold near the profit and improve the nutrition of the solidifying casting. Also used in the manufacture of castings from special bronzes, brass, and some aluminum alloys. Sometimes steel is poured directly through the profits.

However, if, due to an excessively large difference in the cooling rates of individual parts of the casting, there is a danger of stresses and cracks, then to reduce the difference in cooling rates, the metal is brought into less massive parts of the casting.

Simultaneous and uniform solidification and cooling of the casting is achieved by supplying metal to the thin parts of the casting and the appropriate arrangement of feeders, ensuring symmetrical and uniform filling of the mold. This reduces the risk of internal stresses, warping and cracks. A similar supply of metal is used in the manufacture of long castings with walls of varying thickness.

Tapered gating systems better capture slag, reduce air injection, and increase the linear speed of metal passage through the channels of the gating system. They are used in the casting of alloys that are not prone to oxidation and form weak oxide films.

Expanding gating systems reduce the speed of metal movement and ensure smooth filling of the mold cavity without metal oxidation. They are used in the casting of alloys prone to oxidation, forming strong oxide films.

Gating system

a set of channels (elements) through which the melt from a ladle or other casting device is supplied to the working cavity of the casting mold (See Casting mold). Purpose of L. s. - ensuring optimal conditions and duration of mold pouring in order to obtain a casting with clear edges and contours, preventing the entry of non-metallic inclusions (when pouring from a rotary ladle), and during solidification of the alloy - feeding the casting to prevent shrinkage cavities. Elements of HP in accordance with their purpose, they are divided into supply and supply (in some special cases such a division does not exist).

To the supply elements of HP. include: bowl, riser, choke, slag catcher (manifold, gating passage) and feeder ( rice. , A). The melt receiver bowl must contain a sufficient volume of metal for ease of pouring, retention of slag and prevention of air intake. A riser is a vertical (rarely inclined) channel connected to a bowl. Throttle - a narrow channel (or several channels), usually located at the base of the riser, which is a local hydraulic resistance, regulates the filling speed and eliminates vacuum (vacuum) in the riser. A slag trap is a channel, usually of an elongated trapezoidal cross-section, located behind the throttle, used to supply the alloy to the feeders and retain non-metallic inclusions. For more complete retention of slag in HP. arrange local expansions in the slag catcher, use centrifugal slag catchers, filter meshes (for castings made of cast iron - from refractory rod or fireclay mixture, for castings from non-ferrous alloys - from thin sheet steel, for all alloys with a pouring temperature of up to 1350 ° C - from silica fabric ). Slag traps are not needed when pouring molds from a stop ladle (the slag remains in the ladle) and when the density of non-metallic inclusions is close to the density of the alloy (for some non-ferrous alloys). In these cases, a channel called a manifold or runner only distributes the alloy. Feeder is a channel connected to the slag catcher, usually of rectangular cross-section, through which the alloy enters the working cavity of the mold directly or through the profit.

The dimensions of the supply elements are determined mainly by hydrodynamic factors (the design of the HP, pressure, flow rate, and melt velocity).

To the power supply elements of HP. include lateral profit and neck ( rice. , A). Side profit is a compact tide on the side surface of the casting, designed to feed it during cooling and solidification of the alloy. The neck is the narrowed part of the profit that connects it with the casting. The feed elements must harden more slowly than the casting. Their dimensions are determined mainly by thermal factors (thermophysical properties of the alloy and mold), casting properties of the alloy, mass, wall thickness, casting configuration and requirements for it (mechanical properties, tightness, etc.).

When producing thin-walled castings from eutectic alloys (for example, gray cast iron), a short cooling time of the feeders is usually sufficient to feed the castings. In these cases, special power supply elements are not needed and HP. consists only of supply channels ( rice. , b, c, d, e). If a small volume of alloy is required for supply, then the system, along with supply elements, has supply and supply elements, for example, a slag catcher can simultaneously serve as a profit, and a feeder as a neck ( rice. , e).

Depending on the method and place of supply of HP. divided into side, top and rain, siphon, tiered (storey) and slotted. According to the method of molding, horizontal blades are distinguished. with the feeder located in the horizontal plane of the connector and vertical, in which the feeder is located in the vertical plane of the connector or outside the main plane of the mold connector.

Lit.: Dubitsky G.M., Gating systems, M. - Sverdlovsk, 1962; Rabinovich B.V., Introduction to foundry hydraulics, M., 1966; Basic principles of gating, L. - , 1967; Leremplissage des ernpreintes de moules en sable, P., 1966; Hoizmüller A., ​​Kucharcik L., Atlas zur Anschnitt- und Speisertechnik für Guβeisen, Düsseldorf, 1969.

B.V. Rabinovich.

Gating systems: a, b - side; c - rain; g - siphon; d - tiered (storey); e - slotted; 1 - bowl (funnel); 2 - riser; 3 - throttle; 4 - slag catcher; 5 - feeder; 6 - side profit; 7 - neck.

Great Soviet Encyclopedia. - M.: Soviet Encyclopedia. 1969-1978 .

See what a “Gating system” is in other dictionaries:

Gating system, Gating feed system is a system of channels and cavities in a mold through which liquid molten material melt (metal or plastic) is fed into the cavity of an injection mold or injection mold. Elements ... Wikipedia

GUTTER SYSTEM- a system of channels and elements of a casting mold for supplying molten metal to the mold cavity, ensuring its filling and feeding the casting during solidification. Depending on the location in the mold and the method of supplying metal, gatings are distinguished... ... Metallurgical dictionary

Gating system- a system of channels and elements of a casting mold for supplying molten metal into the mold cavity, ensuring its filling and feeding the casting during solidification. Depending on the location in the mold and the method of supplying metal, a gating system is distinguished... ...

gating system- A system of channels and devices for supplying liquid metal (alloy) in a certain mode to the mold cavity, separating non-metallic inclusions and providing power to the casting during solidification. Note According to the design of gating systems... ... Technical Translator's Guide

GUTTER SYSTEM- a set of reservoirs, vertical and horizontal channels that serve to receive and fill the working cavity of the foundry (see) with molten metal, feed (see) during its solidification, as well as to catch the first portions of metal, filter ... Big Polytechnic Encyclopedia

gating system- a system of channels and devices for supplying liquid metal to the cavity of the casting mold, separating non-metallic inclusions and feeding the casting during solidification. The gating system consists of a sprue bowl or pouring funnel,... ... Encyclopedic Dictionary of Metallurgy

A set of channels and cavities (elements) that serve to fill the working cavity of the melt mold. metal, feeding the casting during solidification, trapping the first portions of metal, slag and contaminants. Basic elements of HP (bowl, riser,... ... Big Encyclopedic Polytechnic Dictionary

GREENING SYSTEM BY CONNECTOR- gating system with metal supply along the parting plane. GOST 18169 86 ... Metallurgical dictionary

HORIZONTAL GUTTER SYSTEM- gating system with feeders located in the horizontal plane of the mold connector (Fig. D 14). GOST 18169 86. gating system of simple design WIDTH=391 HEIGHT=281 BORDER=0> gating system with inlet and supply systems... ... Metallurgical dictionary

Vertical gating system- gating system with feeders located in the vertical plane of the mold partition at several levels or vertically. The vertical gating system is divided into upper, rain, siphon, tiered... Encyclopedic Dictionary of Metallurgy

The gating system is a system of channels and mold elements for supplying molten metal to the mold cavity, ensuring its filling and feeding the casting during solidification. In steel casting, a gating system is used, consisting in the simplest version of the following elements (Fig. 7.7): gating funnel 1, riser 2, sump 3, gating passage 4, feeder 5 and profit 7. In more complex versions, it may also include a return riser 8, slot feeder 9 and outflow 10.

Sprue funnel designed to receive molten metal from a casting ladle and direct it to the riser. It has the shape of a truncated cone with a large “base” at the top.

Riser is a vertical or inclined channel for supplying molten metal from the gating funnel to other elements of the gating system or directly into the mold cavity.

Gating stroke- this is a horizontal distribution channel designed to supply molten metal from the riser to the feeders. When pouring the melt into molds from rotary ladles, the gating passage, in addition to the distribution function, must also serve as a slag catcher.

Sump- this is a recess under the riser, designed to weaken the erosive effect on the shape of the falling stream of liquid metal at the beginning of filling the riser.

Feeder is a channel for supplying molten metal from the gate passage to the cavity of the casting mold.

Vypor- this is a channel for removing gases from the mold and controlling its filling with molten metal. It is performed above the top point of the casting cavity in the absence of a profit above it, as well as over closed profits.

Profit as an element of the gating system is discussed in section 7.1.

The gating system may additionally contain a filter for cleaning the melt from slag and sand particles, as well as non-metallic inclusions. The filter is an insert made of refractory material in the form of a mesh, a layer of granules, a rod with thin channels or ceramics with through macropores. It provides coarse or fine cleaning of the melt depending on the size of the filter channels. In addition, filters provide additional hydraulic resistance and make it possible to reduce the flow rate of molten metal through the channels of the gating system.

Requirements for gating systems

A number of requirements are imposed on the gating system, due to the need to obtain high-quality castings at the lowest cost of energy, material and labor resources.

The gating system should:

1) ensure quick but calm filling out of the form. Quick completion is necessary to ensure that the form is completed completely. Slow filling can cause the formation of such defects in castings as underfilling, non-sticking and welding (due to the onset of solidification of the melt before the mold is completely filled), as well as pinching (as a result of prolonged exposure to thermal radiation of liquid steel on the upper walls of the mold). Troubled filling of the mold is also undesirable, since it causes increased defectiveness of castings due to films and gas holes (due to air entrapment by the flow of liquid steel) and blockages (due to erosion of the walls of the mold and core by the jet of liquid metal);

2) be economical in terms of metal consumption. In steel casting, the gating system consumes up to 40-60% of the liquid metal poured into the mold. Therefore, reducing metal consumption for the gating system is an important factor in reducing the cost of manufacturing castings;

3) be technologically advanced, i.e. simple in design, convenient for molding, compact (take up little space in the mold) and easily separated from the casting;

4) ensure the cleaning of liquid metal from slag and sand particles, as well as non-metallic inclusions. If it is necessary to prevent sand and slag particles from entering the casting, the gating passage is used as a slag catcher. And if it is necessary to ensure a higher degree of purification of liquid steel, filters are used that are installed at the junction of the riser with the gate passage or at the junctions of the gate passage with the feeders;

5) promote the consistent solidification of various parts of the casting towards profit. To do this, the metal supply to the casting is carried out to its massive part and away from the location of the refrigerators;

6) promote the dispersion of thermal stresses and do not impede the linear shrinkage of the casting. Otherwise, the concentration of internal stresses may lead to the formation of cracks in the castings;

7) ensure the removal of gases from the rods. To do this, first of all, it should not block the ventilation duct in the sign part of the rod. Otherwise, the castings will be affected by defects in the form of gas holes.

The set of requirements that must be met is determined by the design of the castings, as well as the level and list of requirements placed on them. Castings that do not have high requirements are obtained with a minimum quantity. Accordingly, castings, which are subject to increased requirements, are produced with the maximum number of them. Thus, fulfilling the first three requirements is important in the manufacture of any steel castings. If the casting is subject to increased requirements for contamination with non-metallic inclusions, then a fourth requirement must be added to the first three. The fifth requirement must be met in all cases of manufacturing castings, when the formation of shrinkage cavities is possible in them and shrinkage porosity and looseness are not allowed. If the casting is prone to cracking, then fulfilling the sixth requirement becomes relevant.

Once the metal, such as cast aluminum alloy, is melted and heated to pouring temperature, it is ready to be fed into the mold. A key issue in producing high quality metal castings is the design of a good gating system. This is even more important if the casting is done using gravity rather than pressure casting, low or high.

Pouring molten metal into the mold must be done carefully and accurately. Otherwise, the casting obtained after solidification will have various casting defects, the cause of which was precisely the incorrect pouring of the molten metal:

• too fast flow of liquid metal can cause damage to the casting mold,
• a highly turbulent flow can capture air and various foreign inclusions, and
• Filling the mold too slowly can cause cold plugs to form.

Good gating system

A properly designed gating system ensures proper control of the flow of liquid metal when filling the mold.

An optimal gating system design can:

• reduce the turbulence of the flow of molten metal;
• minimize the content of gases and inclusions in the casting;
• reduce the amount of slag.

An incorrect gating system inevitably leads to problems with the smoothness and continuity of metal flow. The result of this will be poor casting quality. This is especially true for aluminum and its casting alloys, which are very sensitive to disturbances in the smooth flow of the molten aluminum alloy due to increased formation of slag and oxides.

Aluminum alloys react very actively with oxygen to form aluminum oxide. When the aluminum melt flows smoothly, these oxides form on the surface of the melt and remain there. However, if the melt flow is turbulent, these oxides enter the melt and bring gases and inclusions there. Therefore, to avoid interruption of the continuity of flow of molten aluminum, the gating system is designed in such a way as to eliminate problems with air entrapment. This is achieved by preventing the formation of low pressure areas that could cause air to be drawn into the mold.

Gating system elements

The figure below shows a cross section of a typical gating system at . This casting mold illustrates the basic principles of the process of pouring molten metal, including cast aluminum alloys.

A flask is a wooden box in which the molding sand mixture is located.

The lower half is the lower part of the casting mold.

The upper half of the mold is the upper part of the casting mold.

The gating system is a network of channels that are designed to supply molten metal from the entrance to the casting mold into its cavity.

A core is a piece of sand that is inserted into a mold to create the internal parts of a casting.

A toss is a device for attaching a rod.

The gating bowl is the part of the gating system that receives molten metal from the ladle. The sprue bowl controls the flow of metal into the mold. From the gating bowl, the metal flows down the gating riser - the vertical part of the gating system, and then through horizontal channels - gating runners - and finally through controlled entrances - feeders or sprues - into the mold cavity.

Profit is a molten metal reservoir that supplies metal to the mold elements to prevent shrinkage during solidification.

Physical principles of the gating system

To achieve a good gating system design, it is necessary to follow some basic principles. The molten metal behaves according to the fundamental principles of hydraulics. The implications of these principles can be very helpful in understanding the operation of any gating system.

The process of molten metal flow through the gating system into the mold is governed by the principles and concepts of continuum mechanics, such as:

• Bernoulli's theorem;
• principle of continuity;
• Reynolds number.

Bernoulli's theorem for melt flow

Bernoulli's theorem is a consequence of the law of conservation of energy for stationary flow of an incompressible fluid. Bernoulli's theorem for a flow of molten metal is that the sum of potential and kinetic energy at any point in such a flow is constant. Potential energy is determined by the height of the flow relative to a certain reference plane. Kinetic energy depends on the flow speed.

If we neglect friction losses and assume that the entire gating system is under the influence of atmospheric pressure, then from Bernoulli’s theorem it follows that the speed v flow of molten aluminum at the lowest point of the mold feeder depends on the height h, on which the sprue bowl is located according to the formula:

v = (2gh)1/2

From this formula it follows, for example, that the higher the sprue bowl is located, the greater the speed in the sprue at the entrance to the mold.

The principle of continuity of melt flow

The principle of continuity is that for an incompressible liquid - molten metal - under the conditions of impenetrable walls of the gating system, the volumetric flow rate Q remains constant. This means that for any two points of the gating system 1 and 2:

Q = A 1 v 1 = A 2 v 2

Where
A– cross-sectional area of ​​the gating system;
v– melt flow rate through the gating system.

It follows that in order to accelerate the flow of liquid metal, the cross-sectional area of ​​the channels of the gating system must decrease along the flow.

Melt flow characteristics

When designing a gating system, it is very important to take into account the characteristics of the flow of molten metal, which determine whether the flow will be laminar, turbulent or mixed.

Laminar melt flow

In laminar flow, the fluid moves in layers that do not intersect. In this case, laminar flow is not necessarily linear. In laminar flow, the flow follows curved surfaces and flows smoothly in layers. Moreover, layers of liquid can slide relative to each other without any exchange of liquid between the layers.

Turbulent melt flow

In a turbulent flow, secondary random movements are superimposed on the main flow. In this type of flow, fluid exchange already occurs between adjacent layers of fluid. In addition, in such a flow, energy is exchanged between slow and fast particles of the liquid: slow particles accelerate, fast particles slow down.

Reynolds number for a metal melt

The type of flow - laminar or turbulent - is determined by the ratio of the internal inertial forces in the fluid to its internal viscous forces. This ratio is expressed in terms of the dimensionless Reynolds number (Re), which can be simplistically written as follows:

Re= (inertial forces)/(viscous forces)

Viscous forces arise from internal friction in a fluid. Depends on the dynamic viscosity of the liquid. Decrease with increasing temperature.

Inertial forces represent the fluid's resistance to acceleration. They increase with increasing fluid density and flow speed.

In low Reynolds number flow, inertial forces are negligible compared to viscous forces, whereas at high Reynolds number, viscous forces are small compared to inertial forces. Low Reynolds numbers are characterized by laminar flow, while large Reynolds numbers are characterized by turbulent flow.