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N. Sharma and R. Choudhary
turned into a global concern. Therefore, use of renewable energy sources and designing compact and efficient thermal systems are urgent requirements to have a sustainable future. Solar air heater (SAH), act as heat exchangers, uses solar energy to
produce low to moderate temperatures which have a number of applications such
as solar water heaters, in preserving industrial and agricultural products and heating/cooling of buildings (Siddhartha et al. 2012). Admittedly, the solar air heaters
have simple design and easy operation, but also have fewer problems, for instance,
such as less heat storage capacity and low performance. Therefore, substantial efforts
are required to make these thermal systems more appropriate and cost-effective.
For improving the performance of heat exchanging devices, the researchers
and scientists working in the pertinent field have suggested numerous heat transfer enhancement (active/passive) techniques (Webb 1994). Generally, heat transfer
enhancement techniques such as rib turbulators, winglets and extended surfaces control the flow passively and cause turbulence in the near wall region which leads to
reduction in the thermal resistance compared to a conventional heat exchanger and
provide enhanced heat transfer. Along with enhanced heat transfer rates, the pressure penalty also increases with the introduction of rib turbulators (Tariq et al. 2018).
These conflicting perspectives motivate the researchers and designers to find the solution how much should be the modification required in the rib geometry for achieving
the best performance. Significant amount of research activity has been devoted to
the understanding of detailed heat transfer and fluid flow in rib turbulated ducts for
different applications (Kumar et al. 2019; Sharma et al. 2018; Jin et al. 2019). Nowadays, researchers have more focused towards employing soft computing approaches
such as ANN, RSM, Jaya algorithm, GA, and Taguchi method for selecting optimal
blends of design parameters in different heat transfer applications (Rao et al. 2018;
Aidinlou and Nikbakht 2017; Sharma et al. 2017; Nagaiah and Geiger 2019).
It is evident that for predicting the optimal sets of design factors corresponding
to maximum heat transfer, minimum friction factor and highest thermohydraulic
performance, there is no need to perform all the simulations/experiments (a
n
= a ×
a × …n times). Conducting all the experiments/CFD simulations consumes too much
time and also costly affair; but, the Taguchi method effectively predicted the optimum
values with a few experiments/simulations and short span of time. Therefore, in the
present work also Taguchi method has been successfully applied with a very limited
number CFD simulations for prediction of the best sets of design parameters.
Numerous investigations have been performed to design and optimize the design
parameters of heat exchangers mounted with ribs, wire inserts, fins for various heating/cooling applications using Taguchi Method (Yun and Lee 2000; Bilen et al. 2001;
Wang et al. 2009; Aghaie et al. 2015; Chamoli 2015; Caliskan et al. 2016; Kotcioglu
et al. 2018; Sahin et al. 2019). Yun and Lee (2000) systematically analyzed the
influence of slit fins on the aerothermal characteristics using the Taguchi method.
Four design parameters among considered eight parameters have significant contributions, i.e. 39%, 28%, 20% and 9% contributions of fin pitch, slit pattern angle,
length and height of the slit, respectively, on the performance of the slit finned heat
exchanger. The contribution of Reynolds number and rectangular block positions,
i.e. angular displacement, span wise and stream wise disposition, placed on a heat
N. Sharma and R. Choudhary
turned into a global concern. Therefore, use of renewable energy sources and designing compact and efficient thermal systems are urgent requirements to have a sustainable future. Solar air heater (SAH), act as heat exchangers, uses solar energy to
produce low to moderate temperatures which have a number of applications such
as solar water heaters, in preserving industrial and agricultural products and heating/cooling of buildings (Siddhartha et al. 2012). Admittedly, the solar air heaters
have simple design and easy operation, but also have fewer problems, for instance,
such as less heat storage capacity and low performance. Therefore, substantial efforts
are required to make these thermal systems more appropriate and cost-effective.
For improving the performance of heat exchanging devices, the researchers
and scientists working in the pertinent field have suggested numerous heat transfer enhancement (active/passive) techniques (Webb 1994). Generally, heat transfer
enhancement techniques such as rib turbulators, winglets and extended surfaces control the flow passively and cause turbulence in the near wall region which leads to
reduction in the thermal resistance compared to a conventional heat exchanger and
provide enhanced heat transfer. Along with enhanced heat transfer rates, the pressure penalty also increases with the introduction of rib turbulators (Tariq et al. 2018).
These conflicting perspectives motivate the researchers and designers to find the solution how much should be the modification required in the rib geometry for achieving
the best performance. Significant amount of research activity has been devoted to
the understanding of detailed heat transfer and fluid flow in rib turbulated ducts for
different applications (Kumar et al. 2019; Sharma et al. 2018; Jin et al. 2019). Nowadays, researchers have more focused towards employing soft computing approaches
such as ANN, RSM, Jaya algorithm, GA, and Taguchi method for selecting optimal
blends of design parameters in different heat transfer applications (Rao et al. 2018;
Aidinlou and Nikbakht 2017; Sharma et al. 2017; Nagaiah and Geiger 2019).
It is evident that for predicting the optimal sets of design factors corresponding
to maximum heat transfer, minimum friction factor and highest thermohydraulic
performance, there is no need to perform all the simulations/experiments (a
n
= a ×
a × …n times). Conducting all the experiments/CFD simulations consumes too much
time and also costly affair; but, the Taguchi method effectively predicted the optimum
values with a few experiments/simulations and short span of time. Therefore, in the
present work also Taguchi method has been successfully applied with a very limited
number CFD simulations for prediction of the best sets of design parameters.
Numerous investigations have been performed to design and optimize the design
parameters of heat exchangers mounted with ribs, wire inserts, fins for various heating/cooling applications using Taguchi Method (Yun and Lee 2000; Bilen et al. 2001;
Wang et al. 2009; Aghaie et al. 2015; Chamoli 2015; Caliskan et al. 2016; Kotcioglu
et al. 2018; Sahin et al. 2019). Yun and Lee (2000) systematically analyzed the
influence of slit fins on the aerothermal characteristics using the Taguchi method.
Four design parameters among considered eight parameters have significant contributions, i.e. 39%, 28%, 20% and 9% contributions of fin pitch, slit pattern angle,
length and height of the slit, respectively, on the performance of the slit finned heat
exchanger. The contribution of Reynolds number and rectangular block positions,
i.e. angular displacement, span wise and stream wise disposition, placed on a heat