WO2022136944A1

WO2022136944A1 - A flowmeter apparatus

Info

Publication number: WO2022136944A1
Application number: PCT/IB2021/058478
Authority: WO
Inventors: Dasgupta Subhashish; Gu OLIVER-YONGWEI
Original assignee: Abb Schweiz Ag
Priority date: 2020-12-24
Filing date: 2021-09-17
Publication date: 2022-06-30

Abstract

The present invention relates to a flowmeter (103) apparatus designed to be installed in a tube (101). The flowmeter (103) comprises a bluff body (104) having a trapezoidal structure for generating vortices (105) in the tube (101) having a diameter (D) (109), and a flow sensor (106) for generating an electrical signal based on the vortices (105). Further, the bluff body (104) and the flow sensor (106) are separated by a distance (x) (207) such that ratio of the distance (x) (207) to a second width (d') (206) of the bluff body (104) is within the range of 0.832 to 1.248. Furthermore, the flow sensor (106) comprises a first end (210) in an elliptical shape and at least two walls (211) which are tapered, wherein ratio of a first axis (a) (208) to a second axis (b) (209) of the first end (210) is within a range of 1.36 to 2.04.

Description

A FLOWMETER APPARATUS

Technical Field

[001] The current invention relates in general to a flow measurement device and more particularly to a flowmeter apparatus with a flow sensor for measuring a velocity of a fluid.

Background

[002] Generally, a flowmeter is used to measure a velocity of a fluid in a conduit. The flowmeter is installed in-line with a flow direction of the fluid in the conduit. The flowmeter can be of different types including, but not limited to a mass flow meter, a volumetric flowmeter such as vortex flowmeter, and the like. The vortex flowmeter comprises a bluff body that tears the fluid at the edges of the bluff body to generate vortices. The vortices generated by the bluff body is proportional to the velocity of the fluid. A sensor housed in the vortex flowmeter is used to generate an electrical signal upon detecting the vortices. Further, the electrical signal is processed by a processing unit to determine the frequency of the vortices and thereby determining the velocity of the fluid in the conduit.

[003] The measurement of the velocity of the fluid in the conduit is dependent on the strength of the electrical signal generated by the flowmeter. The strength of the electrical signal depends on the accurate detection of the vortices generated in the flowmeter for measuring the velocity of the fluid. Further, when the velocity of the fluid is less under slow operating conditions, the existing flowmeters do not generate electrical signals with a sufficient strength which is required to measure the velocity of the fluid. The electrical signals generated by the flowmeter are susceptible to noise which reduces the strength of the electrical signals and leads to inaccurate measurement of the velocity. Therefore, there is a need to accurately measure the velocity of the fluids under all operating conditions.

[004] In view of the above, there is a need to address at least one of the abovementioned limitations and propose a method and system to overcome the abovementioned problems.

Summary of the Invention

[005] In an embodiment, the present invention relates to a flowmeter apparatus designed to be installed in a tube. The flowmeter comprises a bluff body having a trapezoidal structure for generating vortices in a tube having a diameter (D), and a flow sensor for generating an electrical signal based on the vortices. Further, the bluff body and the flow sensor are separated by a distance (x) such that the ratio of the distance (x) to a second base of the bluff body is within the range of 0.832 to 1.248.

[006] In an embodiment, the present invention discloses one or more dimensions of the bluff body (104) comprising a first width (d) (205) of a first base (201) of the bluff body (104), wherein a ratio of the first width (d) (205) of the first base (201) to the diameter (D) (109) of the tube (101) is within a range of 0.208 to 0.336. Further, one or more dimensions of the bluff body (104) comprises a second width (d’) (206) of a second base (202) of the bluff body (104), wherein the ratio of the second width (d’) (206) of the second base (202) to the first width (d)

(205) of the first base (201) is within the range of 0.08 to 0.12. Furthermore, one or more dimensions of the bluff body (104) comprises a length (L) (204) from the first base (201) to the second base (202) of the bluff body (104), wherein the ratio of the length (L) (204) of the bluff body (104) to the first width (d) (205) of the first base (201) is within the range of 1.12 to 1.68.

[007] In an embodiment, the present invention discloses the ratio of the first width (d) (205) associated with the first base (201) to the diameter (D) (109) of the tube (101) is within the range of 0.26 to 0.28.

[008] In an embodiment, the present invention discloses the ratio of the second width (d’)

(206) associated with the second base (202) to the first width (d) (205) of the first base (201) is 0.1.

[009] In an embodiment, the present invention discloses the ratio of the length (L) (204) of the bluff body (104) to the first width (d) (205) of the first base (201) is 1.4.

[010] In an embodiment, the present invention discloses the ratio of the distance (x) (207) to the second width (d’) (206) of the bluff body (104) is 1.04.

[Oi l] In an embodiment, the present invention discloses the flow sensor (106) is communicatively coupled to a processing unit (107), wherein the processing unit (107) is used for determining a velocity of a fluid (102) in the tube (101) based on the electrical signal received from the flow sensor (106). [012] In an embodiment, the present invention discloses the flow sensor (106) comprises a circular cylindrical shape, wherein the ratio of a first axis (a) (208) to a second axis (b) (209) of the flow sensor (106) is 1, when the ratio of the distance (x) (207) to the second base (202) of the bluff body (104) is within the range of 0.884 to 1.196.

[013] In an embodiment, the present invention discloses a flow sensor associated with a flowmeter apparatus. The flow sensor generates an electrical signal based on the vortices in the flowmeter apparatus. Further, the flow sensor is provided at a distance (x) from a second base of a bluff body provided in the flowmeter apparatus. Furthermore, the flow sensor comprises a first end in an elliptical shape. Finally, the first end of the flow sensor comprises at least two walls which are tapered, wherein a ratio of a first axis (a) to a second axis (b) of the first end is within a range of 1.36 to 2.04.

[014] In an embodiment, the present invention discloses the ratio of the distance (x) (207) to the second base (202) of the bluff body (104) is within the range of 0.832 to 1.248.

[015] In an embodiment, the present invention discloses the ratio of the first axis (a) (208) to the second axis (b) (209) of the flow sensor (106) is 1.7 when the ratio of the distance (x) (207) to the second base (202) of the bluff body (104) is 1.04.

[016] Systems of varying scope are described herein. In addition to the aspects and advantages described in this summary, further aspects and advantages will become apparent by reference to the drawings and with reference to the detailed description that follows.

Brief Description of the Drawings

[017] The subject matter of the invention will be explained in more detail in the following text with reference to preferred exemplary embodiments which are illustrated in the drawings, in which:

[018] Figure 1 shows an exemplary illustration of a flowmeter apparatus installed in a tube, in accordance with an embodiment of the present disclosure;

[019] Figure 2A and FIGURE 2B show exemplary illustration of a bluff body with a trapezoidal structure in perspective view and top view, in accordance with an embodiment of the present disclosure; [020] Figure 2C shows an exemplary illustration of flow sensor and a bluff body separated by a distance (x), in accordance with an embodiment of the present disclosure;

[021] Figure 2D shows an exemplary illustration of a flow sensor with a circular end, in accordance with an embodiment of the present disclosure; and

[022] Figure 2E shows an exemplary illustration of a flow sensor with an elliptical end, in accordance with an embodiment of the present disclosure.

Detailed Description:

[023] The present invention discloses a flowmeter apparatus.

[024] Figure 1 shows an exemplary environment illustration of a flowmeter apparatus installed in a tube.

[025] In an embodiment, a flowmeter (103) is installed in line with a tube (101) configured to allow a fluid (102) to flow. The tube (101) may be manufactured using one or more materials, for example, a metal such as steel, iron, brass, and the like, a glass, a ceramic, and the like. The person skilled in the art appreciates the use of flowmeter (103) with the tube (101) manufactured using other materials in addition to the above mentioned one or more materials. Further, the one or more materials should be considered as examples rather than a limitation. The fluid (102) may represent at least one of a liquid, a gas, and a vapor. Further, the tube (101) carrying the fluid (102) may have a diameter (109) denoted as “D”. The flowmeter (103) may be provided with a fastening mechanism such as a flange (not shown in the figure) for installing the flowmeter (103) in line with the tube (101).

[026] In an embodiment, the flowmeter (103) may include a bluff body (104), a flow sensor (106), a processing unit (107), and a display unit (108). The flowmeter (103) is installed in line with the tube (101) such that the fluid (102) flowing in the tube (101) is separated by the bluff body (104) when the fluid (102) comes in contact with the bluff body (104). The bluff body (104) is placed in the path of the fluid (102) to generate vortices (105) in the flowmeter (103) based on the phenomena of the fluid (102) dynamics. Further, the vortices (105) are detected by the flow sensor (106). For example, the flow sensor (106) may include one of a thermal sensor, a mechanical sensor, a capacitive sensor, a piezoelectric sensor, a strain gauge sensor, an ultrasonic sensor, and like. The flow sensor (106) generates an electrical signal upon detecting the vortices (105) and provides the electrical signal to a processing unit (107). The processing unit (107) may be communicatively coupled to the flow sensor (106) using at least one of a wired interface or a wireless interface. The processing unit (107) may analyze the electrical signal to determine a dominant frequency of the electrical signal. The dominant frequency of the electrical signal may be determined using one or more signal processing techniques such as Fourier transforms. Further, the processing unit (107) may determine the velocity of the fluid (102) in the tube (101) using the below equation:

where ‘V’ denotes the velocity of the fluid (102) in the tube (101), ‘f denotes the dominant frequency of the electrical signal, ‘D’ denotes the diameter (109) of the tube (101), and ‘5_t’ denotes Strouhal number. The person skilled in the art appreciates the use of other techniques in addition to equation (1) for determining the velocity of the fluid (102) using the dominant frequency and the diameter (D) (109) of the tube (101).

[027] In an embodiment, the velocity of the fluid (102) determined by the processing unit (107) may be provided to the user via a display unit (108). The display unit (108) may be communicatively coupled to the processing unit (107) via at least one of the wired interface or the wireless interface.

[028] In an embodiment, generating the vortices (105) under slow operating conditions such as low-pressure conditions, low velocity of the fluid (102) in the tube (101) and the like is dependent on the constructional features of the bluff body (104). Further, detecting the vortices

(105) under the slow operating conditions is dependent on the constructional features of the flow sensor (106) and the distance between the bluff body (104) and the flow sensor (106). The constructional features of the bluff body (104), the constructional features of the flow sensor

(106), and the distance between the bluff body (104) and the flow sensor (106) are predetermined for a given tube (101) having a diameter (D) (109) as detailed below.

[029] In an embodiment, the bluff body (104) installed in the flowmeter (103) may have a trapezoidal structure. For example, the bluff body (104) may have an isosceles trapezoidal structure as shown in FIGURE 2A, where (i) denotes a perspective view and (ii) denotes a top view of the bluff body (104). The bluff body (104) with the isosceles trapezoidal structure has two parallel sides denoted as a first base (201) and a second base (202). Further, two legs (203) of the bluff body (104) taper from the first base (201) to the second base (202) of the bluff body (104) as shown in FIGURE 2A. Furthermore, the distance between the first base (201) and the second base (202) is denoted as the length (L) (204) of the bluff body (104).

[030] In an embodiment, a first width (d) (205) is associated with the first base (201) of the bluff body (104) and a second width (d’) (206) is associated with the second base (202) of the bluff body (104) as shown in FIGURE 2B, where (i) denotes a perspective view and (ii) denotes a top view of the bluff body (104). The first width (d) (205) indicates the length of the first base (201) spanning between the two legs (203) of the bluff body (104) as shown in FIGURE 2B. The second width (d’) (206) indicates the length of the second base (202) spanning between the two legs (203) of the bluff body (104) as shown in FIGURE 2B.

[031] In an embodiment, the flow sensor (106) is separated from the bluff body (104) by a distance (x) (207) as shown in FIGURE 2C, where (i) denotes a perspective view and (ii) denotes a top view of the bluff body (104). Further, the distance (x) (207) between the bluff body (104) and the flow sensor (106) is determined such that a ratio of the distance (x) (207) to the second width (d’) (206) of the second base (202) of the bluff body (104) is within the range of 0.832 to 1.248, i.e.

0.832 < ^ < 1.248 d'

[032] When the second width (d’) (206) of the second base (202) of the bluff body (104) is known, the distance (x) (207) is computed using the below equation: x = R1 * d' . (2) where R1 indicates a value in the range of 0.832 to 1.248.

[033] For example, if the second width (d’) (206) is 15 millimeters, then the flow sensor (106) placed at the distance (x) (207) from the second base (202) of the bluff body (104) is in the range (0.832 * 15 = 12.48 millimeters) to (1.248 * 15 = 18.72 millimeters).

[034] In one embodiment, the ratio of the distance (x) (207) to the second width (d’) (206) of the second base (202) of the bluff body (104) is 1.04, i.e.

The flow sensor (106) is installed at the distance (x) (207) = (1.04 * d’) from the second base (202) of the bluff body (104). The distance (x) (207) between the flow sensor (106) and the bluff body (104) enables the flow sensor (106) to detect the vortices and generate electrical signals with greater signal strength under low flow conditions in the tube (1010.

[035] In an embodiment, the constructional features of the bluff body (104) include at least one of the first width (d) (205), the second width (d’) (206), the length (L) (204), and a height of the bluff body (104) and the like.

[036] In an embodiment, the first width (d) (205) of the first base (201) is determined such that the ratio of the first width (d) (205) of the first base (201) to the diameter (D) (109) of the tube (101) is within a range of 0.208 to 0.336, i.e.

0.208 0.336

[037] When the diameter (D) (109) of the tube (101) is known, the first width (d) (205) of the first base (201) is determined using the below equation: d = R2 * D . (3) where R2 indicates a value in the range of 0.208 to 0.336.

[038] For example, if the diameter (D) (109) of the tube (101) is 75 millimeters, then the first width (d) (205) of the first base (201) of the bluff body (104) is in the range (0.208 * 75 = 15.6 millimeters) to (0.336 * 75 = 25.2 millimeters).

[039] In one embodiment, the ratio of the first width (d) (205) associated with the first base

(201) to the diameter (D) (109) of the tube (101) is within the range of 0.26 to 0.28, i.e.

0.26 0.28

[040] In an embodiment, the second width (d’) (206) of the second base (202) of the bluff body (104) is determined such that the ratio of the second width (d’) (206) of the second base

(202) to the first width (d) (205) of the first base (201) is within the range of 0.08 to 0.12, i.e. d'

0.08 < — < 0.12 d

[041] When the first width (d) (205) of the first base (201) of the bluff body (104) is known, the second width (d’) (206) of the second base (202) of the bluff body (104) is computed using the below equation: d' = R3 * d . (4) where R3 indicates a value in the range of 0.08 to 0.12.

[042] For example, if the first width (d) (205) is 20 millimeters, then the second width (d’) (206) of the second base (202) of the bluff body (104) is in the range (0.08 * 20 = 1.6 millimeters) to (0.12 * 20 = 2.4 millimeters).

[043] In one embodiment, the ratio of the second width (d’) (206) associated with the second base (202) to the first width (d) (205) of the first base (201) is 0.1, i.e. d'

— = 0.1 d

[044] In an embodiment, the length (L) (204) from the first base (201) to the second base (202) of the bluff body (104) is determined such that the ratio of the length (L) (204) of the bluff body (104) to the first width (d) (205) of the first base (201) is within the range of 1.12 to 1.68, i.e.

L

1.12 < - < 1.68 d

[045] When the first width (d) (205) of the first base (201) of the bluff body (104) is known, the length (L) (204) of the bluff body (104) is computed using the below equation:

L = R4 * d . (5) where R4 indicates a value in the range of 1.12 to 1.68.

[046] For example, if the first width (d) (205) is 20 millimeters, then the length (L) (204) of the bluff body (104) is in the range (1.12 * 20 = 22.4 millimeters) to (1.68 * 20 = 33.6 millimeters).

[047] In one particular embodiment, the ratio of the length (L) (204) of the bluff body (104) to the first width (d) (205) of the first base (201) is 1.4, i.e.

L

- = 1.4 d

[048] In an embodiment, when the diameter (D) (109) of the tube (101) for installing the flow meter is obtained, the first width (d) (205) of the first base (201) of the bluff body (104) is determined using the equation (3) based on the range R2. After determining the first width (d) (205), the second width (d’) (206) of the second base (202) of the bluff body (104) is determined using the equation (4) based on the range R3. Furthermore, the length (L) (204) of the bluff body (104) is determined using the equation (5) based on the range R4 after determining the second width (d’) (206). Thereafter, determining the second width (d’) (206), the distance (x) (207) between the bluff body (104), and the flow sensor (106) is determined using the equation (2) based on the range Rl.

[049] In an embodiment, values in the range Rl, R2, R3, and R4 may be selected proportionately i.e., when a value in the range R2 is selected towards an upper limit (i.e., 0.336), the values in the range R3, R4, and Rl is also selected towards the upper limit of the range R3 (i.e., 0.12), R4 (1.68), and Rl (1.248) respectively. In an alternative embodiment, when a value in the range R2 is selected towards a lower limit (i.e., 0.208), the values in the range R3, R4, and Rl is also selected towards the lower limit of the range R3 (i.e., 0.08), R4 (i.e., 1.12), and Rl (i.e., 0.832) respectively. In another embodiment, the values in the ranges Rl, R2, R3, and R4 may be an average value of the upper limit and the lower limit of the ranges Rl, R2, R3, and R4, respectively.

[050] In one particular embodiment, when the first width (d) (205) is 0.27 * D (i.e. diameter (D) (109) of the tube (101)), the second width (d’) (206) is 0.1 * d, the length (L) (204) of the bluff body (104) is 1.4 * d, and the distance (x) (207) between the second base (202) of the bluff body (104) and the flow sensor (106) is 1.04 * d’.

[051] In an embodiment, when the ratio of the distance (x) (207) to the second base (202) of the bluff body (104) is within the range of 0.884 to 1.196, i.e.,

0.884 1.196

the flow sensor (106) including a circular cylindrical shape as shown in FIGURE 2C (ii) and FIGURE 2D is used. The flow sensor (106) includes the circular cylindrical shape when the ratio of a first axis (a) (208) to a second axis (b) (209) of the flow sensor (106) is equal to 1 as shown in FIGURE 2C (ii) and FIGURE 2D, i.e.

[052] In one embodiment, the constructional features of the flow sensor (106) may be determined as detailed below. The flow sensor (106) includes a first end (210) in an elliptical shape as shown in FIGURE 2E such that the ratio of a first axis (a) (208) to a second axis (b) (209) of the first end (210) is within a range of 1.36 to 2.04, i.e.

1.36 < 7 < 2.04 b [053] Further, the first end (210) of the flow sensor (106) comprises at least two walls (211) which are tapered as shown in FIGURE 2E. When the second axis (b) (209) of the flow sensor (106) is known, the first axis (a) (208) of the flow sensor (106) is computed using the below equation: a = RS * b . (6) where R5 indicates a value in the range of 1.36 to 2.04.

[054] For example, if the second axis (b) (209) is 8 millimeters, then the first axis (a) (208) of the flowmeter (103) is in the range (1.36 * 8 = 10.88 millimeters) to (2.04 * 8 = 16.32 millimeters).

[055] In an embodiment, the flow sensor (106) with the elliptical shape may be installed in the flowmeter (103) at the distance (x) (207) from the bluff body (104) such that the distance (x) (207) to the second base (202) of the bluff body (104) is within the range of 0.832 to 1.248, i.e.

0.832 < ^ < 1.248 d'

[056] In one particular embodiment, the elliptical-shaped flow sensor (106) is installed with a first axis (a) (208) and the second axis (b) (209) such that the ratio of the first axis (a) (208) to the second axis (b) (209) of the flow sensor (106) is 1.7 when the ratio of the distance (x) (207) to the second base (202) of the bluff body (104) is 1.04, i.e.

(Z X

— = 1.7 when — = 1.04 b a'

[057] The flowmeter (103) comprises the bluff body (104) having the constructional features such as the first width, the second width, and the length determined using the equations (3), (4), and (5). Further, the flowmeter (103) comprises the flow sensor (106) having the constructional features such as the first axis, and the second axis determined using the equation (6). Furthermore, the bluff body (104) and the flow sensor (106) are separated by the distance (x) (207) determined using equation (1). The flowmeter (103) comprising the buff body and the flow sensor (106) using the equations (1) to (6) helps to generate vortices (105) which are easily detectable using the flow sensor (106) under normal flow conditions, high flow conditions, and low flow conditions of the fluid (102). Further, the flow sensor (106) separated by the distance (x) (207) from the bluff body (104) generates the electrical signals with greater signal strength under low flow conditions as well. Furthermore, the flowmeter (103) reduces the power requirement for amplifying the electrical signals in the processing unit (107) because of the generation of the electrical signals with greater signal strength. The flowmeter (103) increases the accuracy, or the linearity associated with the measurement of the velocity because of the generation of the electrical signals with greater signal strength. The flowmeter (103) generates the electrical signals with greater signal strength under noisy conditions caused due to vibration in the tube (101), and hence increases the accuracy of the measurement of the velocity of the fluid (102). The flowmeter (103) increases the range of measurement for the velocity of the fluid (102) in the tube (101) because of the generation of the electrical signals with greater signal strength.

[058] This written description uses examples to describe the subject matter herein, including the best mode, and also to enable any person skilled in the art to make and use the subject matter. The patentable scope of the subject matter is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.

Referral Numerals:

101 - Tube

102 - Fluid

103 - Flowmeter

104 - Bluff body

105 - Vortices

106 - Flow sensor

107 - Processing Unit

108 - Display Unit

109 - Diameter (D)

201 - Fist base

202 - Second base

203 - Legs

204 - Length (L)

205 - First Width

206 - Second Width

207 - Distance (x) - First axis (a) - Second axis (b) - First end - Walls.

Claims

Claims:

1. A flowmeter (103) apparatus designed to be installed in a tube (101), wherein the flowmeter

(103) comprises a bluff body (104) having a trapezoidal structure for generating vortices (105) in a tube (101) having a diameter (D) (109), and a flow sensor (106) for generating an electrical signal based on the vortices (105), wherein the bluff body (104) and the flow sensor (106) are separated by a distance (x) (207) such that the ratio of the distance (x) (207) to a second base (202) of the bluff body (104) is within the range of 0.832 to 1.248.

2. The flowmeter (103) apparatus as claimed in claim 1, wherein one or more dimensions of the bluff body (104) comprises: a first width (d) (205) of a first base (201) of the bluff body (104), wherein a ratio of the first width (d) (205) of the first base (201) to the diameter (D) (109) of the tube (101) is within a range of 0.208 to 0.336; a second width (d’) (206) of a second base (202) of the bluff body (104), wherein the ratio of the second width (d’) (206) of the second base (202) to the first width (d) (205) of the first base (201) is within the range of 0.08 to 0.12; and a length (L) (204) from the first base (201) to the second base (202) of the bluff body

(104), wherein the ratio of the length (L) (204) of the bluff body (104) to the first width (d) (205) of the first base (201) is within the range of 1.12 to 1.68.

3. The flowmeter (103) apparatus as claimed in claim 2, wherein the ratio of the first width (d) (205) associated with the first base (201) to the diameter (D) (109) of the tube (101) is within the range of 0.26 to 0.28.

4. The flowmeter (103) apparatus as claimed in claim 2, wherein the ratio of the second width (d’) (206) associated with the second base (202) to the first width (d) (205) of the first base (201) is 0.1.

5. The flowmeter (103) apparatus as claimed in claim 2, wherein the ratio of the length (L) (204) of the bluff body (104) to the first width (d) (205) of the first base (201) is 1.4.

6. The flowmeter (103) apparatus as claimed in claim 1, wherein the ratio of the distance (x) (207) to the second width (d’) (206) of the bluff body (104) is 1.04.

7. The flowmeter (103) apparatus as claimed in claim 1, wherein the flow sensor (106) is communicatively coupled to a processing unit (107), wherein the processing unit (107) is used for determining a velocity of a fluid (102) in the tube (101) based on the electrical signal received from the flow sensor (106).

8. The flowmeter (103) apparatus as claimed in claim 1, wherein the flow sensor (106) comprises a circular cylindrical shape, wherein the ratio of a first axis (a) (208) to a second axis (b) (209) of the flow sensor (106) is 1, when the ratio of the distance (x) (207) to the second base (202) of the bluff body (104) is within the range of 0.884 to 1.196.

9. A flow sensor (106) associated with a flowmeter (103) apparatus, wherein the flow sensor (106) generates an electrical signal based on the vortices (105) in the flowmeter (103) apparatus, wherein the flow sensor (106) is provided at a distance (x) (207) from a second base (202) of a bluff body (104) provided in the flowmeter (103) apparatus, wherein the flow sensor (106) comprises a first end (210) in an elliptical shape, wherein the first end (210) of the flow sensor (106) comprises at least two walls (211) which are tapered, wherein a ratio of a first axis (a) (208) to a second axis (b) (209) of the first end (210) is within a range of 1.36 to 2.04.

10. The flow sensor (106) as claimed in claim 9, wherein the ratio of the distance (x) (207) to the second base (202) of the bluff body (104) is within the range of 0.832 to 1.248.

11. The flow sensor (106) as claimed in claim 9, wherein the ratio of the first axis (a) (208) to the second axis (b) (209) of the flow sensor (106) is 1.7 when the ratio of the distance (x) (207) to the second base (202) of the bluff body (104) is 1.04.