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Thesis Chapters by Ujwal Gawai

The Electronic device with increasing processing power, smaller size and greater mobility have ai... more The Electronic device with increasing processing power, smaller size and greater mobility have aided in replacing mechanical device system in many applications like clock etc but at the same time led to a ever increasing challenge to manage their thermal load in a good, stable & cost effective way. These Electronics work best when maintained at a optimal temperature range if the electronic device temperature gets too high above the safe operating temperature and design temperature the device will fail which will in turn cause failure of the machine it was controlling. In this paper we will analyze design consideration of Phase Change Material (PCMs) used as heat sink to increase its temporary thermal storage capacity and maintain fairly stable temperature during the operation of electronic device We will study the addition of fins in heat sink alongwith PCMs to increase the thermal conductivity and allow faster heat transfer between the heat sink and PCM which will reduce the thermal gradient between the two and help maintain temperature within the operating range. In this paper we will analyze the design consideration required for PCM based heat sink and the criteria used for selection of PCM, the criteria for determining the volume of PCM required, the optimum ratio of fin volume to PCM volume, the temperature distribution along the PCM material in the cavity as it is melting and the temperature graph vs time vs heat energy. The results showed that using PCM material in heat sink lead to enhancement of cooling performance, better temperature control.

Papers by Ujwal Gawai

International journal of engineering research and technology, Jun 13, 2017

Compared to single-hole orifices (SOs), multi-hole orifices (MOs) have smaller orifice sizes and ... more Compared to single-hole orifices (SOs), multi-hole orifices (MOs) have smaller orifice sizes and various patterns of orifice distribution. The geometric description of MOs is more complex, increasing the difficulty of MO structural design. Therefore, it is worthwhile to investigate the key factors affecting MO throttle or flow control characteristics and to develop a general MO design method. This work presents a practical geometric design methodology for MOs and applies this procedure in throttle experiments. To describe the MO geometry in detail, the methodology first introduces a comprehensive set of geometric architectures involving orifice arrangement criteria and geometric parameters such as the total orifice number, n; the orifice distribution density and the equivalent diameter ratio. Then, a series of throttle tests in water flow are conducted to investigate the effect of various geometric features on the pressure loss characteristics of MOs. Finally, a simple model to calculate the pressure loss coefficient of MOs is presented. Aiming to find the discharge variations of single hole, 4 hole, 5 hole and 7 hole Orifice by designing and experimenting on them we concluded that 5 hole orifice gave best results as expected.

International Journal of Engineering Research and, 2017

Compared to single-hole orifices (SOs), multi-hole orifices (MOs) have smaller orifice sizes and ... more Compared to single-hole orifices (SOs), multi-hole orifices (MOs) have smaller orifice sizes and various patterns of orifice distribution. The geometric description of MOs is more complex, increasing the difficulty of MO structural design. Therefore, it is worthwhile to investigate the key factors affecting MO throttle or flow control characteristics and to develop a general MO design method. This work presents a practical geometric design methodology for MOs and applies this procedure in throttle experiments. To describe the MO geometry in detail, the methodology first introduces a comprehensive set of geometric architectures involving orifice arrangement criteria and geometric parameters such as the total orifice number, n; the orifice distribution density and the equivalent diameter ratio. Then, a series of throttle tests in water flow are conducted to investigate the effect of various geometric features on the pressure loss characteristics of MOs. Finally, a simple model to calculate the pressure loss coefficient of MOs is presented. Aiming to find the discharge variations of single hole, 4 hole, 5 hole and 7 hole Orifice by designing and experimenting on them we concluded that 5 hole orifice gave best results as expected.

International Journal of Engineering Research, 2014

The designing of heat exchangers is quite complicated, as it needs correct analysis of heat trans... more The designing of heat exchangers is quite complicated, as it needs correct analysis of heat transfer rate and pressure drop estimations apart from issues such as longterm performance and the economic aspect of the equipment. In order to obtain above objective the current experimental investigation has been carried out which shows that heat transfer enhancement take place with increase in turbulent flow where Reynolds number varies from 4000 to 9500 and turbulent flow is developed due to twist tape wavy inserts , the twists ratio are 8.33, 9.79 & 10.42. Performance parameter like pressure drop and heat transfer coefficient is calculated. The obtained results are compared with various combinations such as smooth tube versus twisted tape inserts & plain tape inserts. The above obtained results are studied using a fuzzy inference system named Mamdani and used to expect the output membership functions be fuzzy sets.

International Journal of Advanced Research, 2016

The Electronic device with increasing processing power, smaller size and greater mobility have ai... more The Electronic device with increasing processing power, smaller size and greater mobility have aided in replacing mechanical device system in many applications like clock etc but at the same time led to a ever increasing challenge to manage their thermal load in a good, stable & cost effective way. These Electronics work best when maintained at a optimal temperature range if the electronic device temperature gets too high above the safe operating temperature and design temperature the device will fail which will in turn cause failure of the machine it was controlling. In this paper we will analyze design consideration of Phase Change Material (PCMs) used as heat sink to increase its temporary thermal storage capacity and maintain fairly stable temperature during the operation of electronic device We will study the addition of fins in heat sink alongwith PCMs to increase the thermal conductivity and allow faster heat transfer between the heat sink and PCM which will reduce the thermal gradient between the two and help maintain temperature within the operating range. In this paper we will analyze the design consideration required for PCM based heat sink and the criteria used for selection of PCM, the criteria for determining the volume of PCM required, the optimum ratio of fin volume to PCM volume, the temperature distribution along the PCM material in the cavity as it is melting and the temperature graph vs time vs heat energy. The results showed that using PCM material in heat sink lead to enhancement of cooling performance, better temperature control.

International journal of engineering research and technology, Jun 13, 2017

Compared to single-hole orifices (SOs), multi-hole orifices (MOs) have smaller orifice sizes and ... more Compared to single-hole orifices (SOs), multi-hole orifices (MOs) have smaller orifice sizes and various patterns of orifice distribution. The geometric description of MOs is more complex, increasing the difficulty of MO structural design. Therefore, it is worthwhile to investigate the key factors affecting MO throttle or flow control characteristics and to develop a general MO design method. This work presents a practical geometric design methodology for MOs and applies this procedure in throttle experiments. To describe the MO geometry in detail, the methodology first introduces a comprehensive set of geometric architectures involving orifice arrangement criteria and geometric parameters such as the total orifice number, n; the orifice distribution density and the equivalent diameter ratio. Then, a series of throttle tests in water flow are conducted to investigate the effect of various geometric features on the pressure loss characteristics of MOs. Finally, a simple model to calculate the pressure loss coefficient of MOs is presented. Aiming to find the discharge variations of single hole, 4 hole, 5 hole and 7 hole Orifice by designing and experimenting on them we concluded that 5 hole orifice gave best results as expected.

International Journal of Engineering Research and, 2017

Compared to single-hole orifices (SOs), multi-hole orifices (MOs) have smaller orifice sizes and ... more Compared to single-hole orifices (SOs), multi-hole orifices (MOs) have smaller orifice sizes and various patterns of orifice distribution. The geometric description of MOs is more complex, increasing the difficulty of MO structural design. Therefore, it is worthwhile to investigate the key factors affecting MO throttle or flow control characteristics and to develop a general MO design method. This work presents a practical geometric design methodology for MOs and applies this procedure in throttle experiments. To describe the MO geometry in detail, the methodology first introduces a comprehensive set of geometric architectures involving orifice arrangement criteria and geometric parameters such as the total orifice number, n; the orifice distribution density and the equivalent diameter ratio. Then, a series of throttle tests in water flow are conducted to investigate the effect of various geometric features on the pressure loss characteristics of MOs. Finally, a simple model to calculate the pressure loss coefficient of MOs is presented. Aiming to find the discharge variations of single hole, 4 hole, 5 hole and 7 hole Orifice by designing and experimenting on them we concluded that 5 hole orifice gave best results as expected.

International Journal of Engineering Research, 2014

The designing of heat exchangers is quite complicated, as it needs correct analysis of heat trans... more The designing of heat exchangers is quite complicated, as it needs correct analysis of heat transfer rate and pressure drop estimations apart from issues such as longterm performance and the economic aspect of the equipment. In order to obtain above objective the current experimental investigation has been carried out which shows that heat transfer enhancement take place with increase in turbulent flow where Reynolds number varies from 4000 to 9500 and turbulent flow is developed due to twist tape wavy inserts , the twists ratio are 8.33, 9.79 & 10.42. Performance parameter like pressure drop and heat transfer coefficient is calculated. The obtained results are compared with various combinations such as smooth tube versus twisted tape inserts & plain tape inserts. The above obtained results are studied using a fuzzy inference system named Mamdani and used to expect the output membership functions be fuzzy sets.

International Journal of Advanced Research, 2016