Patent Description:
The basic objective in any structural design is to provide a structure capable of resisting all the loads without failure during the intended life. Power transformers designed to distribute large amounts of power, such as substation and distribution class power transformers, may suffer due to overheat. For instance, if the cooling is compromised, the transformer temperature may rise above desired values. Such a rise in temperature may result in the outright failure of the power transformer and at a minimum will result in some damage and an accelerated loss of life. That is, over time excessive heating will reduce transformer life and lead to premature failure which will affect the ability of a utility company to supply uninterrupted supply of power to its customers and will cost the operating utility significant replacement costs.

Transformers generally include cooling systems to remove heat generated when large loads are applied to the transformers (i.e., when large currents are drawn from and through the transformer). Maintaining the transformer temperature below a critical value enables the transformer to handle a designated power capacity or to increase the power handling capability of the transformer. The cooling systems are designed to remove heat to help keep the transformer and its components below predetermined critical temperatures. Generally, the cooling system has the transformer contained within a liquid (e.g., oil) filled tank with or without oil pumps being used to circulate the fluid through radiators attached to the tank. The operation of the radiator is vital for the transformer to deliver its designated power capacity.

The radiators are also used in automobiles, generators, etc., but the design and the performance of the product varies and are meant for a specific application. That is, generally, the purpose of radiator is the same for various applications, be it transformers, automobiles, generators, etc., but the design and the performance of the product shall manifest its performance in the field of application and shall be an economical solution. Systems may suffer because of incorrect use of radiator design for oil cooling. In addition to the thermal performance, the radiator shall also be capable of withstanding the external forces like seismic, vibration, wind force, external force on the radiator due to the accumulation of ice-berg in the cold countries and the self-weight of radiator and the oil weight. <CIT> discloses a heat dissipating element according to the preamble of claim <NUM>.

There are different design implementations of the radiator known in the art. The most common and widely used radiators include tubular type radiators. In a tubular-type radiator, an upper side which receives the heated oil from the transformer and a lower side which supplies back the oil to the transformer are connected by a series of tubes through which the oil passes. Air passes around the outside of the tubes, absorbing heat from the oil (or water) in passing. In some examples, fins are placed around the tubes to improve heat transfer. In such tubular-type radiators, tubes are welded to the top and lower sides which may lead to structural integrity concerns. The tubes being straight are generally disposed close to heat dissipating portion of the transformer and thus may have less exposure to cool air from the atmosphere. Thus, large capacity transformer requires the radiator to have a larger number of tubes, and further tubes of larger length, to achieve required thermal performance. Thus, the tubular-type radiators are not economical in practice for power transformer applications.

Moreover, the transformer industry is increasingly switching over to environmental friendly ester-based oil for transformers from mineral-based oil. Ester-based oil has come into the market with its major advantage of being bio-degradable. But one of the major limitations of the ester-based oil is its high viscosity. In actual scenario for high viscous oil, if the hydraulic dimensions of the tubes in the radiator are small, the frictional forces are more. If the hydraulic dimensions are large, radiator's manufacturers endure from manufacturing process limitation and transformers will endure from excess oil consumption. This becomes a major setback in the thermal performance of the tubular-type radiators.

The present disclosure has been made in view of such considerations, and it is an object of the present disclosure to provide a heat dissipating element for a radiator which overcomes the problems associated with the known designs, including structural concerns, and provide better cooling performance for the radiator.

The present invention provides a heat dissipating element for a radiator, as defined in Claim <NUM> of the appended claims. Also provided is a radiator as defined in Claim <NUM>, and a method of manufacturing a heat dissipating element as defined in Claim <NUM>. Details of certain embodiments are set out in the dependent claims.

In a first aspect, a heat dissipating element for a radiator is disclosed. The heat dissipating element comprises a body having a top portion, a bottom portion and a middle portion. The heat dissipating element further comprises a plurality of flutes defined in the body. Each of the plurality of flutes provides a continuous channel to allow for flow of a fluid therein. The heat dissipating element also comprises an inlet port provided at the top portion to receive the fluid and supply the fluid to each of the plurality of flutes, and an outlet port provided at the bottom portion to collect the fluid from each of the plurality of flutes. In the heat dissipating element, one or more of the plurality of flutes extend longitudinally downwards and diverge laterally outwards from the inlet port in the top portion of the body, extend longitudinally downwards in the middle portion of the body, and extend longitudinally downwards and converge laterally inwards towards the outlet port in the bottom portion of the body.

A cross-section of each one of the plurality of flutes has a hexagonal profile, formed of two trapeziums mirrored to each other along bases thereof.

In one or more embodiments, a sheet surface of the body between the plurality of flutes is corrugated.

In one or more embodiments, the plurality of flutes comprises nine flutes.

In one or more embodiments, the fluid comprises ester oil.

In another aspect, a radiator for cooling a device is disclosed. Herein, the device has a fluid flowing therethrough to extract heat therefrom. The radiator comprises a first collector pipe for connection with the device to be cooled to receive the fluid therefrom. The radiator also comprises a second collector pipe for connection with the device to be cooled to supply back the fluid thereto. The radiator further comprises one or more heat dissipating elements according to the first aspect. The inlet port of the or each heat dissipating element is in fluid communication with the first collector pipe to receive the fluid therefrom; and the outlet port of the or each heat dissipating element is in fluid communication with the second collector pipe to supply the collected fluid thereto.

In one or more embodiments, a longitudinal length of each of the one or more heat dissipating elements is in a range of <NUM> up to <NUM>.

In one or more embodiments, a number of the one or more heat dissipating elements is in a range from <NUM> to <NUM>.

In yet another aspect, a method of manufacturing a heat dissipating element for a radiator is disclosed. The method comprises forming a first metal sheet to define a plurality of first open profiles extending along a longitudinal length thereof. The method further comprises forming a second metal sheet to define a plurality of second open profiles extending along a longitudinal length thereof, complementary to the plurality of predefined open profiles formed in the first metal sheet. The method further comprises joining the first metal sheet and the second metal sheet so as to form a body having a top portion, a bottom portion and a middle portion, and a plurality of flutes defined therein from the plurality of first open profiles and the plurality of second open profiles closing each other, with each of the plurality of flutes providing a continuous channel to allow for flow of a fluid therein. The method further comprises providing an inlet port at the top portion of the body to receive the fluid and supply the fluid to each of the plurality of flutes. The method further comprises providing an outlet port at the bottom portion of the body to collect the fluid from each of the plurality of flutes. Herein, one or more of the plurality of flutes extend longitudinally downwards and diverge laterally outwards from the inlet port in the top portion of the body, extend longitudinally downwards in the middle portion of the body, and extend longitudinally downwards and converge laterally inwards towards the outlet port in the bottom portion of the body.

Each of the plurality of first open profiles and each of the plurality of second open profiles is in form of a trapezium opened at a base thereof, and wherein a cross-section of each one of the plurality of flutes has a hexagonal profile formed of two trapeziums mirrored to each other along the bases thereof.

In one or more embodiments, the plurality of first open profiles and the plurality of second open profiles are formed in the first metal sheet and the second metal sheet, respectively, using one or more of: rolling operation, stamping operation.

In one or more embodiments, the first metal sheet and the second metal sheet is made of at least one of CRCA IS <NUM> CR2 grade steel, CRCA IS <NUM> CR3 grade steel, CRCA IS <NUM> CR5 grade steel, and austenitic stainless grade steel.

For a more complete understanding of example embodiments of the present disclosure, reference is now made to the following descriptions taken in connection with the accompanying drawings in which:.

In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. It will be apparent, however, to one skilled in the art that the present disclosure is not limited to these specific details.

Reference in this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. The appearance of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Further, the terms "a" and "an" herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced items. Similarly, various requirements are described which may be requirements for some embodiments but not for other embodiments.

Furthermore, in the following detailed description of the present disclosure, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be understood that the present disclosure may be practiced without these specific details. In other instances, well-known methods, procedures, components, and circuits have not been described in detail so as not to unnecessarily obscure aspects of the present disclosure.

Some portions of the detailed description that follows are presented and discussed in terms of a process or method. Although steps and sequencing thereof are disclosed in figures herein describing the operations of this method, such steps and sequencing are exemplary. Embodiments are well suited to performing various other steps or variations of the steps recited in the flowchart of the figure herein, and in a sequence other than that depicted and described herein.

Referring to <FIG>, illustrated is a diagrammatic perspective view of a device (represented by reference numeral <NUM>) which needs to be cooled. In the illustrated embodiment of <FIG>, the device <NUM> is a transformer device, with the two terms being interchangeably used hereinafter for the purposes of the present disclosure. However, it may be appreciated that the device <NUM> may be an automobile, a generator, or any similar device which may also be needed to be cooled (using radiator, as described later) without any limitations. As shown, the transformer device <NUM> includes a housing (as represented by reference numeral <NUM>) which may enclose the actual power transformer (not visible). As is known in the art, the primary and secondary windings of the power transformer have some resistance. As current flows through the windings, heat is generated which is a function of the winding resistance multiplied by the square of the current. A considerable amount of heat may be generated by, and within, the power transformer, particularly when the load is increased and more current flows through the power transformer's primary and secondary windings.

The heat generated within the power transformer causes a rise in the temperature of the windings and in the space surrounding the windings and all around the power transformer. When the temperature rises above a certain level many problems are created. For example, the resistance of the (copper) transformer windings increases as a function of the temperature rise. The resistance increase causes a further increase in the heat being dissipated, for the same value of load current, and further decreases the efficiency of the transformer. With increased temperature, the power transformer may also be subjected to increased eddy current and other losses. The temperature rise may also cause unacceptable expansion (and subsequent contraction) of the wires. Also, the insulation of the windings and other components may be adversely affected. Temperatures above designed and desirable levels result in undesirable stresses being applied to the power transformer and or its components. This may cause irreversible damage to the power transformer and its associated components and at a minimum creates stresses causing a range of damages which decrease its life expectancy.

In the transformer device <NUM>, the power transformer is cooled by immersing it in a fluid (e.g., oil, with the two terms being interchangeably used). For this purpose, the housing <NUM> is filled with the oil to extract heat from the power transformer. Now, this fluid needs to be transferred out of the housing <NUM> to be cooled and to be recirculated back into the housing <NUM> to again be used for heat extraction from the power transformer. The transformer device <NUM> includes one or more radiators (represented by reference numeral <NUM>) for the said purpose. The radiators <NUM> are heat exchangers used to transfer thermal energy from one medium to another for the purpose of cooling and/or heating, such as, in the present case, from the oil to the atmosphere. The radiators <NUM> usually provide a large amount of cooling surface to be in contact with large amounts of air so that it spreads through the oil to cool efficiently.

In the illustrated embodiment, the transformer device <NUM> is shown to include six radiators <NUM> (four being visible); however, it may be appreciated that the number of radiators <NUM> implemented for the transformer device <NUM> may depend on the rating of the power transformer thereof. There are different types and ratings of the transformer device <NUM> which may warrant as few as one radiator <NUM> or as many as tens of radiators <NUM>. Further, it may be appreciated that arrangement of the radiators <NUM> in the illustration of <FIG> is exemplary only, and shall not be construed as limiting to the present disclosure. Generally, the radiators <NUM> may be arranged in the transformer device <NUM> in any suitable arrangement without departing from the spirit and the scope of the present disclosure.

As may be seen from <FIG>, the transformer device <NUM> includes an outflow pipe <NUM>, for each radiator <NUM>, connecting the corresponding radiator <NUM> and the housing <NUM>, which may allow to transfer the fluid from the inside of the housing <NUM> to the corresponding radiator <NUM>. It may be contemplated that the transformer device <NUM> may include one or more pumps (not shown) to provide pumping action for said transfer of the fluid. Further, the transformer device <NUM> includes an inflow pipe (generally marked by reference numeral <NUM>, not particularly visible in <FIG>), for each radiator <NUM>, connecting the corresponding radiator <NUM> and the housing <NUM>, to receive the cooled fluid from the corresponding radiator <NUM> to be transferred back to the inside of the housing <NUM>. Also, as shown in <FIG>, each radiator <NUM> includes a first collector pipe <NUM> disposed in connection with the housing <NUM>. In particular, the first collector pipe <NUM> is disposed in connection with the outflow pipe <NUM> to receive the fluid at the corresponding radiator <NUM> to be cooled from the inside of the housing <NUM>. Also, each radiator <NUM> includes a second collector pipe <NUM> disposed in connection with the housing <NUM>. In particular, the second collector pipe <NUM> is disposed in connection with the inflow pipe <NUM> to transfer the cooled fluid from the corresponding radiator <NUM> to the inside of the housing <NUM>.

Referring to <FIG> in combination, as shown, the first collector pipe <NUM> of the radiator <NUM> includes a first flange <NUM> at end thereof to allow for connection with the outflow pipe <NUM> to receive the fluid at the corresponding radiator <NUM>. For this purpose, the first flange <NUM> may be provided with apertures (represented by reference numeral <NUM>). It may be contemplated that the outflow pipe <NUM> may also have a corresponding flange with apertures (not shown), to mate with the apertures <NUM> in the first flange <NUM> of the first collector pipe <NUM> by using fasteners or the like (not shown). Similarly, the second collector pipe <NUM> of the radiator <NUM> includes a second flange <NUM> at end thereof to allow for connection with the inflow pipe <NUM> to receive the fluid at the corresponding radiator <NUM>. For this purpose, the second flange <NUM> may be provided with apertures (represented by reference numeral <NUM>). It may be contemplated that the inflow pipe <NUM> may also have a corresponding flange with apertures (not shown), to mate with the apertures <NUM> in the second flange <NUM> of the second collector pipe <NUM> by using fasteners or the like (not shown).

Also, as shown in <FIG>, the radiator <NUM> may include one or more lugs which may be used to lift the radiator <NUM>. In an example, as shown, one of the lugs <NUM> may be provided on the first collector pipe <NUM> and another lug <NUM> may be provided on the second collector pipe <NUM>. That said, it may be appreciated that one or more of the lugs <NUM>, <NUM> may be provided on any other location on the radiator <NUM> suitable for bearing weight of the radiator <NUM> without any limitations. In an example, the lugs <NUM>, <NUM> may be designed to couple with a lifting mechanism using a shackle and pin arrangement for the said purpose of lifting the radiator <NUM>, as required. Further, the radiator <NUM> may include one or more plugs. In an example, as shown, one of the plugs <NUM> may be provided on the first collector pipe <NUM> and another plug <NUM> may be provided on the second collector pipe <NUM>. The plugs <NUM>, <NUM> are used to allow for releasing air and/or draining oil present in the radiator <NUM>, via the first collector pipe <NUM> and the second collector pipe <NUM>, such as, in case of need of emptying the radiator <NUM> for dismantling and/or transportation thereof.

Further, as shown in <FIG>, the radiator <NUM> includes one or more heat dissipating elements <NUM>. Herein, the heat dissipating elements <NUM> are in the form of fins exposed to the atmosphere. The heat dissipating elements <NUM> are configured to allow the oil to travel inside thereof, causing transfer of heat from the oil to the atmospheric air thereby. In the illustrated embodiments, the radiator <NUM> is shown to include five heat dissipating elements <NUM>; however, it may be contemplated that the radiator <NUM> may include more or lesser number of heat dissipating elements <NUM> depending on the cooling requirement, which in turn may be based on the rating of the transformer device <NUM> or the like, without departing from the spirit and the scope of the present disclosure. In the present embodiments, the heat dissipating elements <NUM> are in the form of sheets with certain thicknesses at certain sections thereof (as discussed later in lot more detail). Also, as shown, the heat dissipating elements <NUM> are arranged parallel to each other in the radiator <NUM>.

Referring now to <FIG> in combination, different views of one of the heat dissipating elements <NUM> are illustrated. In the illustrations of <FIG>, the heat dissipating element <NUM> is shown to be disposed between the first collector pipe <NUM> and the second collector pipe <NUM>. The heat dissipating element <NUM> provides a body <NUM> having a top portion <NUM>, a bottom portion <NUM> and a middle portion <NUM>. The body <NUM> is extending between the first collector pipe <NUM> and the second collector pipe <NUM>, with the top portion <NUM> being disposed within the first collector pipe <NUM> and the bottom portion <NUM> disposed within the second collector pipe <NUM>, and the middle portion <NUM> being exposed to the atmosphere. Also, as shown, the heat dissipating element <NUM> includes an inlet port (generally marked by reference numeral <NUM>) in fluid communication with the first collector pipe <NUM> to receive the fluid therefrom. Further, the heat dissipating element <NUM> includes an outlet port (generally marked by reference numeral <NUM>) in fluid communication with the second collector pipe <NUM> to supply the collected fluid thereto.

Further, as shown, the heat dissipating element <NUM> includes a plurality of flutes <NUM> defined in the body <NUM>. Herein, the flutes <NUM> are in the form of channels defined in the body <NUM>, extending from the top portion <NUM> to the bottom portion <NUM> thereof. Each of the plurality of flutes <NUM> provides a continuous channel to allow for flow of the fluid therein. As discussed, the inlet port <NUM> in the heat dissipating element <NUM> is provided at the top portion <NUM> thereof and is in fluid communication with the first collector pipe <NUM> to receive the fluid therefrom. Herein, the received fluid from the first collector pipe <NUM> via the inlet port <NUM> is passed to the flow inside the flutes <NUM> in the heat dissipating element <NUM>. The received fluid flows in each of the flutes <NUM> in the heat dissipating element <NUM>, from the top portion <NUM>, passing through the middle portion <NUM> and then to the bottom portion <NUM> in the body <NUM>. Further, as discussed, the outlet port <NUM> in the heat dissipating element <NUM> is provided at the bottom portion <NUM> thereof and is in fluid communication with the second collector pipe <NUM> to supply the collected fluid thereto. Herein, the fluid coming from the top portion <NUM> and the middle portion <NUM> to the bottom portion <NUM> in the body <NUM> is passed via the oautlet port <NUM> of the heat dissipating element <NUM> to the second collector pipe <NUM>.

Now, as shown, the plurality of flutes <NUM> are extending across a longitudinal length of the body <NUM> in the heat dissipating element <NUM>. Further, the plurality of flutes <NUM> are distributed across a lateral length of the body <NUM> in the heat dissipating element <NUM>. In an example, the plurality of flutes <NUM> may be distributed equidistant to each other across the lateral length of the body <NUM>; however other suitable distribution arrangement(s) may also be implemented without departing from the spirit and the scope of the present disclosure. According to embodiments of the present disclosure, one or more of the plurality of flutes <NUM> are extending longitudinally downwards and diverging laterally outwards from the inlet port <NUM> in the top portion <NUM> of the body <NUM>, extending longitudinally downwards in the middle portion <NUM> of the body <NUM>, and extending longitudinally downwards and converging laterally inwards towards the outlet port <NUM> in the bottom portion <NUM> of the body <NUM>. That is, generally, each flute <NUM> has a diverging-converging profile, with the flutes <NUM> towards one of the longitudinal side (edge) from a longitudinal axis along a lateral centre of the body <NUM> being mirror-image to the flutes <NUM> towards other of the longitudinal side (edge) from the said longitudinal axis of the body <NUM>.

Such diverging-converging profiles of the flutes <NUM> help to divert the oil flowing therein away from the first collector pipe <NUM> and the lateral centre of the body <NUM>, and towards the flutes <NUM> at the lateral sides of the body <NUM>, in the heat dissipating element <NUM>. In other words, the diverging and converging profile of the heat dissipating element <NUM> allows at least some of the received oil from the first collector pipe <NUM> to diverge to the flutes <NUM> towards the lateral sides of the body <NUM>. As may be contemplated, the surrounding temperature near middle (lateral centre) of the body <NUM> would be more compared to the lateral sides of the body <NUM>, in the heat dissipating element <NUM>. Thus, the flutes <NUM> towards the lateral sides of the body <NUM> get higher free flow of fresh air. This allows the oil present in such flutes <NUM> towards the lateral sides of the body <NUM> to cool the oil therein more quickly because of more contact with the atmospheric air. This creates a thermographic profile of parabolic in shape for the heat dissipating element <NUM> (as discussed later in detail).

The diverging-converging profiles of the flutes <NUM> may provide higher hydraulic dimensions for the flutes <NUM>, thus helping with better flow of the oil therein. As used herein, the "hydraulic dimension" refers to characteristic length used to calculate the dimensionless number to determine if the flow is laminar or turbulent. In general, the hydraulic dimension represents an effective cross sectional area of the flute <NUM> which contributes for the oil to flow through. Thereby, the heat dissipating element <NUM> enables to allow for flow of high-viscosity fluid therein, which may not be possible with traditional designs. In the present embodiments, the fluid used in the transformer device <NUM> to be cooled by the heat dissipating elements <NUM> of the radiator <NUM> comprises ester oil. The ester oil is highly viscous oil, but may help with better heat dissipation and is also bio-degradable. This is in contrast to mineral oils which are used in traditional set-ups because of their limitations to handle high-viscosity fluids, and which are also non-biodegradable thus posing harm to the environment when disposed. It may also be appreciated that the diverging profiles of the flutes <NUM> at the top portion <NUM> may also help to distribute the oil as received more uniformly between the multiple flutes <NUM> as compared to, say, traditional tubular design in which the oil is distributed from a top tank and usually the channels towards the centre may receive more flow of oil as compared to the channels towards the lateral sides, which is undesirable.

As may be seen, the body <NUM> of the heat dissipating element <NUM> is made of sheet materials with the flutes <NUM> defined therein (as discussed later in more detail). Thus, the body <NUM> of the heat dissipating element <NUM> provides a significantly larger surface area as compared to, say, traditional tubular design which has individual distant tubes therein. Thus, in the present heat dissipating element <NUM>, the body <NUM> may also contribute towards dissipation of heat from the oil flowing in the flutes <NUM> to the atmospheric air. In fact, the larger surface area of the body <NUM> may allow to provide significantly more heat transfer, thus contributing to the thermal performance of the heat dissipating element <NUM>. Also, in the present embodiments, the body <NUM> of each heat dissipating element <NUM> is made of steel (as discussed later in more detail). Therefore, it may be possible to have as much as up to <NUM> heat dissipating elements <NUM> in the single radiator <NUM> with the present design, which is not possible with traditional designs. Further, in an embodiment, a sheet surface (as marked by reference numeral <NUM>) between the plurality of flutes <NUM>, i.e., the area between the flutes <NUM> of the body <NUM>, is corrugated. As may be understood by a person skilled in the art, such corrugated profile of the sheet surface <NUM> may further enhance the heat transfer from the body <NUM>, improving overall thermal performance of the heat dissipating element <NUM>.

Referring to <FIG>, illustrated is a top view of the radiator <NUM> showing the heat dissipating elements <NUM> therein. As discussed, in the illustrated embodiments, the radiator <NUM> is shown to include five (<NUM>) number of heat dissipating elements <NUM>. It may be contemplated that the radiator <NUM> may include from <NUM> up to <NUM> number of heat dissipating elements <NUM> therein, depending on the rating, and thus heating load, of the transformer device <NUM>. <FIG> illustrates a top view of the heat dissipating element <NUM>. As shown, the heat dissipating element <NUM> is connected to the first collector pipe <NUM> (and similarly to the second collector pipe <NUM>) at the lateral centre thereof. In general, selection of the number of radiators <NUM> depends on rating of the transformer device <NUM>. There are different types and rating of the transformer device <NUM> which requires each of the radiators <NUM> to include the heat dissipating elements <NUM> to be as low as just <NUM> panels and up to <NUM> panels, and with length of each of the heat dissipating elements <NUM> starting from <NUM> up to <NUM>. This is in contrast to traditional designs in which there are many limitations in the selection of number of tubes and length of the tubes for a radiator and its structural integrity as a product. In the present embodiments, the size and the number of heat dissipating elements <NUM> in the radiator <NUM> is not particularly limited and depends only on its intended use for the transformer device <NUM> to be cooled.

<FIG> illustrates a cross-section view of the heat dissipating element <NUM> showing in detail the individual flutes <NUM> therein. In the present exemplary embodiment, the heat dissipating element <NUM> includes nine number of flutes <NUM>. That is, the plurality of flutes <NUM> includes nine number of flutes <NUM>. It may be appreciated that the said number of flutes <NUM> is a preferred embodiment, and is not limiting to the present disclosure. As shown, a cross-section of each one of the plurality of flutes <NUM> is in the form of two trapeziums mirrored to each other along bases thereof. <FIG> illustrates a detailed section view of the individual flute <NUM>. It may be seen that the flute <NUM> has a hexagonal profile, particularly formed of two trapeziums mirrored to each other along bases (as represented by dashed line) thereof. Such profile may help with better flow of the fluid inside the flute <NUM>, thus improving the thermal performance of the heat dissipating element <NUM>, and thereby the overall radiator <NUM>. In general, the better cooling efficiency is achieved with optimum oil channel spacing due to the distribution and the diverging-converging profiles of the flutes <NUM>, allowing the high viscous oil, such as ester oil (with viscosity about <NUM>-<NUM> times more than mineral oil), to flow smoothly. Thus, even the transformer device <NUM> with large rating/capacity, requiring large amount of heat dissipation, may be cooled using the radiators <NUM> of the present disclosure.

Referring to <FIG>, illustrated is an exemplary graph <NUM> indicative of temperature rise of oil with time in the radiator <NUM>, in accordance with one or more exemplary embodiments of the present disclosure. As shown in the graph <NUM>, the top oil temperature in the radiator <NUM> for ester oil rises faster and stabilizes earlier (as compared to mineral oil in the traditional designs) and the difference between measured top oil and bottom oil temperature for the radiator <NUM> shows a better temperature drop. This is achieved because of the optimum oil flow in the flutes <NUM>, which helps in reducing the frictional losses, thus speed of flow of fluid remain optimum and thus the heat dissipating elements <NUM> in the radiator <NUM> dissipate more heat, which advantageously affects the overall cooling capacity of the radiator <NUM> for use with the transformer device <NUM>.

Referring to <FIG>, illustrated is an exemplary graph <NUM> indicative of rate of heat dissipation from the heat dissipating element <NUM> of the radiator <NUM> across lateral length thereof for different ambient temperature conditions, in accordance with one or more exemplary embodiments of the present disclosure. In testing using thermal imaging apparatus, it was confirmed that the oil was cooled quickly at the outer flutes <NUM> (i.e., the flutes <NUM> towards the lateral sides) as compared to the flutes <NUM> at the lateral centre of the body <NUM> of the heat dissipating element <NUM>. As explained in the preceding paragraphs, this is due to more exposure to the ambient air for the outer flutes <NUM> as compared to the flutes <NUM> at the lateral centre of the body <NUM> of the heat dissipating element <NUM>. This is confirmed in the graph <NUM>, as shown, the heat dissipation increases as the distance from the centre of the body <NUM> of the heat dissipating element <NUM> increases.

The present disclosure further provides a method of manufacturing a heat dissipating element (such as, the heat dissipating element <NUM>) for a radiator (such as, the radiator <NUM>). <FIG> illustrates a flow chart listing steps involved in the present method (represented by reference numeral <NUM>) of manufacturing the heat dissipating element <NUM> for the radiator <NUM>. It may be appreciated that the teachings as described above, may apply mutatis mutandis to the method as described herein below.

At step <NUM>, the method <NUM> includes forming a first metal sheet to define a plurality of first open profiles extending along a longitudinal length thereof. Herein, the first metal sheet may be made of steel. Specifically, the first metal sheet may be made of steel material with high formability, such as one of: CRCA IS <NUM> CR2 grade steel, CRCA IS <NUM> CR3 grade steel, CRCA IS <NUM> CR5 grade steel grade steel, and austenitic stainless grade steel. Each of the plurality of first open profiles is in the form of a trapezium opened at base thereof (as shown in reference to <FIG>). The plurality of first open profiles are formed in the first metal sheet using one or more of: rolling operation, stamping operation. In particular, each of the plurality of first open profiles has a diverging section, a straight section, and a converging section. The said diverging section and converging section of the first open profiles may be formed by stamping operation, whereas the straight section may be formed by rolling operation. At step <NUM>, the method <NUM> includes forming a second metal sheet to define a plurality of second open profiles extending along a longitudinal length thereof. Herein, the second metal sheet may be made of steel. Specifically, the second metal sheet may be made of steel material with high formability, such as one of: CRCA IS <NUM> CR2 grade steel, CRCA IS <NUM> CR3 grade steel, CRCA IS <NUM> CR5 grade steel grade steel, and austenitic stainless grade steel (similar to the first metal sheet). Each of the plurality of second open profiles is in the form of a trapezium opened at base thereof (as shown in reference to <FIG>). The plurality of second open profiles are formed in the second metal sheet using one or more of: rolling operation, stamping operation. In particular, each of the plurality of second open profiles has a diverging section, a straight section, and a converging section (complementary to the defined sections in the first metal sheet). The said diverging section and converging section of the second open profiles may be formed by stamping operation, whereas the straight section may be formed by rolling operation.

At step <NUM>, the method <NUM> includes joining the first metal sheet and the second metal sheet so as to form a body (such as, the body <NUM>) having a top portion (such as, the top portion <NUM>), a bottom portion (such as, the bottom portion <NUM>) and a middle portion (such as, the middle portion <NUM>), and a plurality of flutes (such as, the plurality of flutes <NUM>) defined therein from the plurality of first open profiles and the plurality of second open profiles closing each other, with each of the plurality of flutes <NUM> providing a continuous channel to allow for flow of a fluid therein. It may be appreciated that because of the complementary defined diverging sections, the straight sections and the converging sections in the first metal sheet and the second metal sheet, when the two sheets are joined, the plurality of flutes <NUM> are formed with the diverging-converging profiles. Further, because of each of the plurality of first open profiles and each of the plurality of second open profiles being in form of a trapezium opened at base thereof, a cross-section of each one of the plurality of flutes <NUM> is in the form of two trapeziums mirrored to each other along the bases thereof. In the present embodiments, the two sheets may be joined by multi-spot resistance welding technique, as may be performed by automated robots or the like. Further, in some examples, neck trimming technology may be implemented to eliminate non- uniform welding of the two sheets by using loop welding methodology.

At step <NUM>, the method <NUM> includes providing an inlet port (such as, the inlet port <NUM>) at the top portion <NUM> of the body <NUM> to receive the fluid and supply the fluid to each of the plurality of flutes <NUM>. The said inlet port <NUM> is disposed in fluid communication with the first collector pipe <NUM> to receive the fluid therefrom, and to supply the fluid to each of the plurality of flutes <NUM>. At step <NUM>, the method <NUM> includes providing an outlet port (such as, the outlet port <NUM>) at the bottom portion <NUM> of the body <NUM> to collect the fluid from each of the plurality of flutes <NUM>. The said outlet port <NUM> is disposed in fluid communication with the second collector pipe <NUM> to supply the collected fluid thereto. Herein, the first collector pipe <NUM> and the second collector pipe <NUM> may be made of mild steel, and the heat dissipating element(s) <NUM> may be welded therewith for forming such connections. The present disclosure provides optimum hydraulic dimensions for the oil channels provided by the flutes <NUM>, increasing thermosyphon effect of cooling (i.e., Oil Natural Air Natural (ONAN) cooling) because of less frictional resistance compared to traditional designs. The present disclosure further solves the problem of the transformer industry switching to ester-based oils (because of their bio-degradability) by allowing use of high-viscosity fluids in the radiator <NUM>.

Thus, the method <NUM> of the present disclosure provides the radiator <NUM> with the heat dissipating elements <NUM> in which one or more of the plurality of flutes <NUM> are extending longitudinally downwards and diverging laterally outwards from the inlet port <NUM> in the top portion <NUM> of the body <NUM>, extending longitudinally downwards in the middle portion <NUM> of the body <NUM>, and extending longitudinally downwards and converging laterally inwards towards the outlet port <NUM> in the bottom portion <NUM> of the body <NUM>. This design of the radiators <NUM> is unique with stamped plate, and with a divergent and convergent pattern for diverting the oils away from the first collector pipe <NUM>. This helps the oil from the first collector pipe <NUM> to travel away from the lateral centre of the body <NUM>, helping the oil at the end flutes <NUM> to cool quickly before being supplied to the second collector pipe <NUM> to be used for cooling of the transformer device <NUM>, creating a thermographic profile of parabolic in shape. In some examples, the radiator <NUM> as formed may be galvanized by hot dip technique to increase the life thereof. In some examples, the radiator <NUM> as formed is coated with duplex coating system (HDG + Paint) to provides better edge protection, excellent corrosion resistance, to serve for long periods with minimum maintenance at site.

In traditional designs of the radiators, for high viscous oil if the hydraulic dimension of the channels is small, the frictional forces are more. If the hydraulic dimension is large, the manufacturing of the radiator may be limited by process limitations and the transformers will endure from excess oil consumption. This becomes a major setback in the thermal performance of the radiator. The present disclosure provides the radiator(s) <NUM> with the heat dissipating elements <NUM> with channels in the form of flutes <NUM> having shape as diverging from the inlet port <NUM> from the top portion <NUM> with the first collector pipe <NUM> to the middle portion <NUM>, and converging from the middle portion <NUM> to the outlet port <NUM> at the bottom portion <NUM> leading to the second collector pipe <NUM>. Such diverging-converging profile helps with the oil to be distributed evenly through all the flutes <NUM>, and also enhances better heat dissipation through the heat dissipating elements <NUM>. In particular, the diverging-converging profile helps in faster temperature drop from the lateral sides (edges) of the heat dissipating elements <NUM>, showing a parabolic curve in temperature profile. The present disclosure allows the heat dissipating elements <NUM> to accommodate larger collector pipes <NUM>, <NUM> and additional flutes <NUM> to carry excess oil because of higher thermal performance, thus increasing the overall cooling effect provided by the radiator(s) <NUM> for the transformer device <NUM>.

Claim 1:
A heat dissipating element (<NUM>) for a radiator (<NUM>), the heat dissipating element (<NUM>) comprising:
a body (<NUM>) having a top portion (<NUM>), a bottom portion (<NUM>) and a middle portion (<NUM>);
a plurality of flutes (<NUM>) defined in the body (<NUM>), with each of the plurality of flutes (<NUM>) providing a continuous channel to allow for flow of a fluid therein;
an inlet port (<NUM>) provided at the top portion (<NUM>) to receive the fluid and supply the fluid to each of the plurality of flutes (<NUM>); and
an outlet port (<NUM>) provided at the bottom portion (<NUM>) to collect the fluid from each of the plurality of flutes (<NUM>),
characterised in that a cross-section of each one of the plurality of flutes (<NUM>) has a hexagonal profile, formed of two trapeziums mirrored to each other along bases thereof, and
one or more of the plurality of flutes (<NUM>) extend longitudinally downwards and diverge laterally outwards from the inlet port (<NUM>) in the top portion (<NUM>) of the body (<NUM>), extend longitudinally downwards in the middle portion (<NUM>) of the body (<NUM>), and extend longitudinally downwards and converge laterally inwards towards the outlet port (<NUM>) in the bottom portion (<NUM>) of the body (<NUM>).