Claims:We claim:

1. A method for configuring a canopy with in-line entry and exit of air for generator-set by computational fluid dynamics, wherein the method comprises the steps of:

• Measuring temperature by means of thermocouples at a plurality of critical locations within existing canopy for obtaining the thermal performance of the canopy;

• Measuring the air-velocity at a plurality of critical locations on canopy inlet by making a grid for obtaining the flow performance of the canopy;

• Repeating the temperature and velocity measurements for different load conditions of:
(i) 0%,
(ii) 50%,
(iii) 70%,
(iv) 100%, and
(v) 110%;
• Analyzing the thermal performance and flow performance of the existing canopy;

• Setting the targets for total mass flow-rate across the canopy and air-velocity across the critical points within the canopy using the formula:

Rho x A x V x 3600 kg/hr
wherein,
- Rho = density of air in kg/m3,
- A = Area of canopy inlet in m2, and
- V = Average air-velocity at canopy inlet in m/sec,

• Carrying out CFD Simulation for existing canopy configuration to quantify flow and thermal performance of the following parameters:
- Radiator fan speed,
- Radiator heat transfer data including at least five different flow-rates of air and coolant,
- Intercooler heat transfer data including five different flow rates of primary and secondary air,
- Drawing pressure versus discharge plot for radiator and intercooler for five different flow rates with air as working fluid,
- Temperature of air at canopy inlet and radiator outlet,
- Temperature of coolant at radiator inlet,
- Temperature of air at intercooler inlet,
- Coolant properties like density, specific heat, viscosity and conductivity,
- Thermal boundary conditions like surface temperature of each component within the canopy;

• Validating the output of CFD simulation with the actual test results;

• Refining the CFD model further, if the difference between the existing canopy data and test data in more than 5%;

• Optimizing the CFD model to arrive at the optimum canopy configuration by incorporating CAE and NVH requirements;

• Fine-tuning the canopy configuration by means of a plurality of iterations;

• Finalizing the canopy configuration and making a prototype;

• Final testing by measuring temperature by means of thermocouples at a plurality of critical locations within the optimized canopy configuration for obtaining the thermal performance of the canopy;

• Measuring the velocity at a plurality of critical locations on the inlet of the optimized canopy configuration by making a grid for obtaining the flow performance of the canopy;

• Repeating the temperature and velocity measurements for different load conditions of:
(i) 0%,
(ii) 50%,
(iii) 70%,
(iv) 100%, and
(v) 110%.
2. Method as claimed in claim 1, wherein the thermocouples are mounted at thirty different locations of the critical components.

3. Method as claimed in claim 2, wherein the critical components are cylinder block; cylinder head; alternator; exhaust manifold and exhaust pipe.

4. Method as claimed in claim 1, wherein the air-velocity is measured at twelve different critical locations on canopy inlet by making a grid, the air- velocity being at least 1 m/sec at these critical locations.

5. A compact canopy with inline air inlet and outlet configured by the method as claimed in claim 1, wherein the footprint of the canopy is reduced by 25 to 30%, preferably by 20%.

6. Compact canopy as claimed in claim 5, wherein the material cost is reduced by 5 to 15 %, preferably by 10%.

7. Compact canopy as claimed in anyone of the claims 5 to 6, wherein the canopy is for a 125 kVA generator set.

8. Compact canopy as claimed in anyone of the claims 5 to 7, wherein the radiator fan is at least a 10-blade fan providing higher air-mass flow rate by 8 to 15%, preferably about 10%.

Dated: this day of 25th April, 2016. SANJAY KESHARWANI
APPLICANT’S PATENT AGENT , Description:FIELD OF INVENTION

The present invention relates to improving the performance and reducing footprint in generator-sets. In particular, the present invention relates to a more compact canopy for generator-sets. More particularly, the present invention relates to a canopy configured with inline air inlet and outlet. The invention also relates to a Computational Fluid Dynamics (CFD) driven methodology therefor.

BACKGROUND OF THE INVENTION

The generator-set is predominantly a diesel generator-set which is a packaged unit consisting of a packaged combination of diesel engine, generator and other ancillary devices such as base, canopy, systems for sound attenuation and control, circuit breakers, cooling circuit and starting system. The diesel engine is operably connected to an alternator to generate electric power. The generator set is used as emergency power supply equipment, particularly in areas where an uninterrupted electric supply is not available for running machinery and/or where the existing power availability needs to be boosted for a short duration of time for specific purposes.

The applicants have filed an earlier patent application 1952/MUM/2014 entitled: “A double decker diesel generator set to reduce the footprint thereof”.
In this application, the alternator chassis is used for mounting the alternator above the engine. The alternator cooling arrangement is also provided on its chassis, which consists of a passage, a suction vent for sucking fresh air through a suction louver and after passing over and around the alternator, the heated exhaust air is mixed with the fresh air coming in through the engine side inlet louver and then passes through radiator to be exhausted to the atmosphere. The geometry of the passage is configured by smart positioning for mixing hot air with fresh air coming from engine compartment and then passing towards the radiator fan. This generator-set was conceived to occupy less floor space, particularly for premium value areas.
This is achieved by a double-storeyed structure, not directed to reorient the sound sources to prevent localization and uniform distribution of noise within the canopy thereof.

A study entitled “Design and development of noise suppression system for domestic generators” published in the European Scientific Journal, December 2013/Special/Edition Vol.4, e- ISSN 1857 – 7431 and conducted by Umar Hammad, Dr. Ahmad Aizaz, Dr. Abid Ali Khan and Taimur Qureshi of CAE, National University of Sciences and Technology, Islamabad, Pakistan concerns a feasibility study of a simple and effective design of an acoustic enclosure for portable generators aimed at reducing the radiated noise. It involves a multi-disciplinary work comprising acoustics, heat transfer and material science. Heat generation and requirement of cooling air leads to a heat transfer model with internal forced convection. The design is a balance of noise control and thermal management. Noise generating areas have been identified and conventional passive noise control techniques have been used to control and reduce noise and acoustic barriers and insulations are used to control the noise propagation at its transmission path.

This study concludes that heat transfer calculations play an equally important role in designs, where enhanced cooling requirement in the enclosed spaces for the generator is inversely proportional to the noise control methodologies. Therefore, an appropriate balance between the two opposing requirements is an essential step in such designs. Although, the study has demonstrated the effectiveness of sound proof canopy for the domestic generator by lowering its noise category from ‘very loud’ to ‘moderately loud’, this study was restricted to domestic generators and high-capacity generator sets, e.g. 100kVA which were not covered under this study.

DISADVANTAGES WITH THE PRIOR ART

The problem with the existing canopies of the generator sets is that they are not very effective from the point of view of their thermal performance due to the side-in top-out type of configuration. They also occupy larger space, i.e. have higher footprint. Moreover, the existing canopies experience localization of noise from exhaust and fan at a single point. Another problem with the existing canopies is that they produce a higher level of noise and there is issue of ingress of rain water through the canopy outlet.

DESCRIPTION OF THE PRESENT INVENTION

In order to model the conventional canopy by using the high end design tool like Computational Fluid Dynamics (CFD) by means of the functionality of other engines, a series of simulations were carried out by the applicants to predict the flow and thermal performance for the given boundary conditions. The existing canopies were comprehensively tested and enough insight of the flow and thermal performance thereof was obtained to validate the CFD predictions with the test data so obtained. The detailed evaluation of different configurations of canopies was carried out to replicate the desired modifications. This helped in quantifying the effect on the thermal performance of these canopies.

Accordingly, an optimum canopy configuration with the inlet and outlet thereof disposed in series is arrived at. However, it was also detected that this configuration of inlet and outlet of the canopy disposed in series still caused localization of noise from exhaust and fan at a single point, which needed further improvement to reorient the sound sources for preventing such localization of noise, so that the noise gets distributed to all over to reduce the overall noise emitting from the canopy of the generator set. This straight out flow from the fan brought the flow noise directly at the measurement location. This is achieved by a series of modifications done in the conventional canopy configuration.

These modifications include:

a) Reversing the fan rotation,

b) Adjusting the fan rpm,

c) Changing the fan outlet location,

d) Reversing the outlet louvers orientation,
e) Changing the canopy height,

f) Removing the radiator grid,

g) Removing the duct, louvers,

h) Adding the partition,

i) Increasing the length of partitions, and

j) Changing the blade numbers in the fan.

OBJECTS OF THE INVENTION

Some of the objects of the present invention - satisfied by at least one embodiment of the present invention - are as follows:

An object of the present invention is to provide a generator-set, in which the inlet and outlet of the canopy are configured in series.

Another object of the present invention is to provide a generator-set, which prevents the localization of noise from exhaust and fan at a single point.

Still another object of the present invention is to provide a generator-set, which reorients the sound sources to distribute noise to all points.

Yet another object of the present invention is to provide a generator-set, which improves the overall NVH performance of the generator-set.

These and other objects and advantages of the present invention will become more apparent from the following description when read with the accompanying figures of drawing, which are, however, not intended to limit the scope of the present invention in any way.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a method for configuring a canopy with in-line entry and exit of air for generator-set by computational fluid dynamics, wherein the method comprises the steps of:
• Measuring temperature by means of thermocouples at a plurality of critical locations within existing canopy for obtaining the thermal performance of the canopy;

• Measuring the air-velocity at a plurality of critical locations on canopy inlet by making a grid for obtaining the flow performance of the canopy;

• Repeating the temperature and velocity measurements for different load conditions of:
(i) 0%,
(ii) 50%,
(iii) 70%,
(iv) 100%, and
(v) 110%;
• Analyzing the thermal performance and flow performance of the existing canopy;

• Setting the targets for total mass flow-rate across the canopy and air-velocity across the critical points within the canopy using the formula:

Rho x A x V x 3600 kg/hr
wherein,
- Rho = density of air in kg/m3,
- A = Area of canopy inlet in m2, and
- V = Average air-velocity at canopy inlet in m/sec,

• Carrying out CFD Simulation for existing canopy configuration to quantify flow and thermal performance of the following parameters:
- Radiator fan speed,
- Radiator heat transfer data including at least five different flow-rates of air and coolant,
- Intercooler heat transfer data including five different flow rates of primary and secondary air,
- Drawing pressure versus discharge plot for radiator and intercooler for five different flow rates with air as working fluid,
- Temperature of air at canopy inlet and radiator outlet,
- Temperature of coolant at radiator inlet,
- Temperature of air at intercooler inlet,
- Coolant properties like density, specific heat, viscosity and conductivity,
- Thermal boundary conditions like surface temperature of each component within the canopy;

• Validating the output of CFD simulation with the actual test results;

• Refining the CFD model further, if the difference between the existing canopy data and test data in more than 5%;

• Optimizing the CFD model to arrive at the optimum canopy configuration by incorporating CAE and NVH requirements;

• Fine-tuning the canopy configuration by means of a plurality of iterations;

• Finalizing the canopy configuration and making a prototype;

• Final testing by measuring temperature by means of thermocouples at a plurality of critical locations within the optimized canopy configuration for obtaining the thermal performance of the canopy;

• Measuring the velocity at a plurality of critical locations on the inlet of the optimized canopy configuration by making a grid for obtaining the flow performance of the canopy;

• Repeating the temperature and velocity measurements for different load conditions of:
(i) 0%,
(ii) 50%,
(iii) 70%,
(iv) 100%, and
(v) 110%.

Typically, the thermocouples are mounted at thirty different locations of the critical components.

Typically, the critical components are cylinder block; cylinder head; alternator; exhaust manifold and exhaust pipe.
Typically, the air-velocity is measured at twelve different critical locations on canopy inlet by making a grid, the air- velocity being at least 1 m/sec at these critical locations.

In accordance with the present invention, there is also provided a compact canopy with inline air inlet and outlet in which the footprint is reduced by 25 to 30%, preferably by 20%.

Typically, the material cost is reduced by 5 to 15 %, preferably by 10%.

Typically, the canopy is for a 125 kVA generator set.

Typically, the radiator fan is at least a 10-blade fan providing higher air-mass flow rate by 8 to 15%, preferably about 10%.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will be briefly described with reference to the accompanying drawings, which include:

Figure 1a shows a schematic view of a conventional canopy configuration for a generator set.

Figure 1b shows a schematic view of the internal components of a conventional canopy

Figure 2a shows a typical section view of the conventional configuration of the canopy shown in Figure 1 depicting the velocity across it.

Figure 2b shows a typical conventional configuration of the canopy shown in Figure 1 depicting the velocity vector plot across it.

Figure 2c shows a typical Computational Fluid Dynamics (CFD) path-lines diagram obtained for conventional configuration of the canopy shown in Fig.1.
Figure 3a shows the velocity distribution across the internal components of the canopy shown in Figure 1.

Figure 3b shows the side view of the internal components of the canopy shown in Figure 1 depicting the velocity distribution across it.

Figure 4a shows a schematic view of the canopy for a generator set configured in accordance with the present invention.

Figure 4b shows the detail schematic of all the internal components of the canopy of Figure 4a.

Figure 4c shows the improved fan for the canopy of Figure 4a configured in accordance with the present invention.

Figure 4d shows different sections of the canopy of Figure 4a depicting the velocity distribution across it.

Figure 4e shows different sections from rear view of the canopy of Figure 4a depicting the velocity distribution across it.

Figure 4f shows the typical velocity contour obtained by Computational Fluid Dynamics (CFD) for the front-view of the canopy shown in Figure 4a.

Figure 4g shows the velocity contour obtained by Computational Fluid Dynamics (CFD) for the rear-side view of the canopy shown in Figure 4f.

Figure 5a shows the perspective front-view of the conventional canopy of a generator-set.

Figure 5b shows the perspective rear-view of the canopy of Figure 5a for a generator-set.

Figure 6a shows the front-view of the canopy shown in Figure 5.
Figure 6b shows the left-side view of the canopy shown in Figure 5.

Figure 6c shows the right-side view of the canopy shown in Figure 5.

Figure 6d shows the top-view of the canopy shown in Figure 5.

Figure 7a shows the front-view of the canopy configured in accordance with the present invention.

Figure 7b shows the left-side view of the canopy of Figure 7a.

Figure 7c shows the right-side view of the canopy of Figure 7a.

Figure 7d shows the top-view of the canopy of Figure 7a.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

In the following, different embodiments of the present invention will be described in more details with reference to the accompanying drawings without limiting the scope and ambit of the present invention in any way.

Figure 1a shows a schematic top view of a conventional configuration of the canopy 10 for a generator set. Here, initially the canopy inlet & outlet is at atmospheric.

Figure 1b shows a schematic front view of a conventional configuration of the canopy 10 for a generator-set shown in Figure 1a. It includes a plurality of baffles 12, partition 14, alternator 16, control panel 18, air-cleaner 20, diesel engine 30, oil-pan 32, radiator, intercooler and fan unit 34, outlet duct 36 and fuel tank 40.

Figure 2a shows a typical Computational Fluid Dynamics (CFD) diagram for distribution of the volume-flow for the conventional canopy 10 shown in Fig. 1. The air-volume entering the canopy 10 through the inlet 12 is directed in largest amount 11 towards the air-cleaner 20 and diesel engine 30 and only a small portion 13 is directed towards alternator 16. However, the air-volume in the outlet duct 36 forms eddy, which is not very effective because of non-uniform volume–flow distribution. The fan is running at 1500 rpm. The circulating air has a density of about 1.147 kg/m3 and the viscosity is 1.789e-05 kg/m-s. Here, the fluid volume is about 5.838 m3 for an inlet area of 0.578 m2 and outlet area of 0.426 m2.

Figure 2b shows a typical Computational Fluid Dynamics (CFD) mass-flow diagram obtained for the conventional canopy 10 shown in Figure 1. Here, although the mass-flow of the air entering the canopy 10 through the inlet 12 is directed substantially uniformly around the air-cleaner 20 and diesel engine 30, the air mass-flow in the outlet duct 36 is concentrated substantially in the center of the duct, however does not exit effectively because of its density in-one side of the outlet duct 36. CFD results show a mass-flow rate of about 7551 kg/hour.

Figure 2c shows a typical Computational Fluid Dynamics (CFD) path-lines diagram obtained for the conventional configuration of the canopy shown in Figure 1. The main stream 11 passes around the air-cleaner 20 and engine 30 and gets scattered around the radiator, intercooler and fan unit 34 and forms eddy in outlet duct 36 before exiting the canopy 10.

Figure 3a shows a typical Computational Fluid Dynamics (CFD) velocity plot obtained for the front view in the conventional configuration of the canopy shown in Figure 1.

Figure 3b shows the Computational Fluid Dynamics (CFD) velocity plot obtained for the rear-side view in the conventional configuration of the canopy shown in Figure 1. The typical velocity values in m/sec obtained in different regions thereof are also shown inset in this figure.

Figure 4a shows a schematic top view of the canopy 100 for a generator set configured in accordance with the present invention.
Figure 4b shows the schematic front-view of the canopy 100 of Figure 4a. It includes an inlet louver 114, alternator 116, control panel 118, air-cleaner 120, diesel engine 130, oil-pan 132, radiator, intercooler and fan unit 134, an outlet louver 138 and fuel tank 140.

Figure 4c shows the fan 136 for the canopy 100 of Figure 4a. In contrast to the fan (7 blade) used in the conventional canopy of Figure 1, this fan 136 consists of at least 10 blades for substantially enhancing the flow-rate delivered within the canopy. This fan rotates at about 1800 rpm as against the earlier used fan rotating at 1500 rpm. Therefore, about 10-12% increased flow rate is obtained within the new canopy.

Figure 4d shows the schematic layout of the front-view of the canopy 100 of Figure 4a depicting the velocity contour obtained by CFD. The velocity contours across this canopy 100 show that critical regions such as the exhaust manifold, engine block 130, head and alternator 116 experience a velocity between 2 to 4 m/sec. This demonstrates that there is no stagnation present across these critical areas and hence the possibility of hot spots is almost negligible.

Figure 4e shows the schematic layout of the rear-side view of the canopy of Figure 4a depicting the velocity contour obtained by CFD.

Figure 4f shows the typical velocity contour obtained by Computational Fluid Dynamics (CFD) for the front-view of the canopy shown in Figure 4a.

Figure 4g shows the velocity contour obtained by Computational Fluid Dynamics (CFD) for the rear-side view of the canopy shown in Figure 4f.

Figure 5a shows the perspective front-view of the conventional canopy 10 of a generator-set. The canopy includes a base frame 2, left vertical panel 4, a horizontal tie-member front 6, a central panel 8, a right vertical panel 22, a right-side end vertical panel 24, an inlet tie-member 26, inlet louvres 28, a canopy outlet 36, top sheet 42, muffle cover 44 and a control panel door 50.

Figure 5b shows the perspective rear-view of the canopy 10 of Figure 5a. The canopy 10 further includes a common door 46, a horizontal tie-member rear 48, a rain deflector 52, a rear panel 54, a vertical panel rear 56 and a central beam 60.

Figure 6a shows the front-view of the canopy shown in Figure 5 having a length ‘L’.

Figure 6b shows the left-side view of the canopy shown in Figure 5 having a width ‘W’.

Figure 6c shows the right-side view of the canopy shown in Figure 5.

Figure 6d shows the top-view of the canopy shown in Figure 5.

Figure 7a shows the front-view of the canopy configured in accordance with the present invention having a substantially reduced length ‘l’.

Figure 7b shows the left-side view of the canopy of Figure 7a.

Figure 7c shows the right-side view of the canopy of Figure 7a having a substantially reduced width ‘w’.

Figure 7d shows the top-view of the canopy of Figure 7a.

TESTS CONDUCTED & RESULTS THEREOF:

In order to determine the thermal performance of the conventional canopy and the canopy configured in accordance with the present invention, a variety of tests were conducted to ascertain the correlations for the critical constructional features of the canopy:

Mass-flow rate (kg/hr) Correlation %
CFD At canopy inlet At air-cleaner inlet Test net
Conventional Canopy 7551.17 7872.24 624.56 7872.24 96
NEW Canopy 8372.47 8498.43 - - 98.51

Moreover, a plurality of thermocouples was located within the canopy at different locations to obtain correlations at each of these locations.

The results are summarized below:

Thermo-couple No. Location => 0% 75% 100% 110%
1 2 3 4
1 Fan RH Bottom 42.2 46.1 45.1 42.1
2 Fan RH Top 41.9 44.7 43.7 41.1
3 Fan LH Top 42.5 49.8 50.7 47.6
4 Fan LH Bottom 45.4 54.2 55.1 55.3
5 LH Block 42.1 41.7 34.5
6 RH Block 68.2 80.1 91.7 89
7 Intake manifold middle 45.2 50 52.1 50.1
8 Exhaust outlet 127.3 373 423 457.4
9 Air-filter inlet 40 40.6 38.6 37.8
10 Exhaust pipe 49.7 104.2 113.9 116
11 Control box 41.7 44.7 45.7 44.4
12 Fan shroud 44.4 50.4 52 50
13 Canopy outlet 51.3 69.7 78 77.3
14 Canopy inlet 39.9 40.8 36.8 35.1
15 Alternator 44.6 50.2 56.5 56.3

However, the canopy in accordance with the present invention configured by using a 10 blade fan exhibited a substantially improved higher mass-flow rate of 8372.47 kg/hour at slightly higher velocity 3.51 m3 and with significantly lower fluid volume of 3.368 m3.

These comparative results are summarized below:

Conventional canopy NEW Canopy
Mass-flow rate (kg/hr) 7551.20 8372.47
Velocity at inlet (m/sec) 3.162 3.51
Fluid volume (m3) 5.838 3.368
Inlet area (m2) 0.578 0.578
Outlet area (m2) 0.426 0.578

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE

The serial-in serial-out canopy configured with a ten-blade fan configured in accordance with the present invention has the following advantages:
• Offers higher mass-flow rate,
• Better thermal performance with lower fluid volume,
• Offers lower noise-level at the outlet,
• Prevents stagnation across critical-areas,
• Prevents formation of hot-spots,
• Prevents localization of noise from exhaust and fan at single point,
• Provides 10% reduction in material cost in new canopy,
• The issue of rain water entry through outlet is resolved,
• Reduced foot print by 20%, i.e. about 10 ft2 area without affecting the performance,
• Better NVH product with reduced size,
• Smallest & first of its kind design in 125KvA market, and
• CFD, NVH and CAE processes have been established.

Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, shall be understood to implies including a described element, integer or method step, or group of elements, integers or method steps, however, does not imply excluding any other element, integer or step, or group of elements, integers or method steps. In the claims and the description, the terms “containing” and “having” are used as linguistically neutral terminologies for the corresponding terms “comprising”.

The use of the expression “a”, “at least” or “at least one” shall imply using one or more elements or ingredients or quantities, as used in the embodiment of the disclosure in order to achieve one or more of the intended objects or results of the present invention. Furthermore, the use of the term “one” shall not exclude the plurality of such features and components described.

The description provided herein is purely by way of example and illustration. The various features and advantageous details are explained with reference to this non-limiting embodiment in the above description in accordance with the present invention. The descriptions of well-known components and manufacturing and processing techniques are consciously omitted in this specification, so as not to unnecessarily obscure the specification.

In the previously detailed description, different features have been summarized for improving the conclusiveness of the representation in one or more examples. However, it should be understood that the above description is merely illustrative, but not limiting under any circumstances. It helps in covering all alternatives, modifications and equivalents of the different features and exemplary embodiments.

Many other examples are directly and immediately clear to the skilled person because of his/her professional knowledge in view of the above description. Therefore, innumerable changes, variations, modifications, alterations may be made and/or integrations in terms of materials and method used may be devised to configure, manufacture and assemble various constituents, components, subassemblies and assemblies according to their size, shapes, orientations and interrelationships.

While considerable emphasis has been placed on the specific features of the preferred embodiment described here, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiments without departing from the principles of the invention.

These and other changes in the preferred embodiment of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

The exemplary embodiments were selected and described in order to be able to best represent the principles and their possible practical application underlying the invention. Thereby, the skilled persons can optimally modify and use the invention and its different exemplary embodiments with reference to the intended use.