Papers by Praveen Guruprasanna (JSHL-R & D)
Development of Thermal Performance Test Method for Coolant Heater Core Products for Electric Vehicle Applications
SAE technical paper series, Oct 5, 2022
Estimation of Brazing Temperature in Aluminium Heat Exchangers by Using Alpha Phase Measurement Techniques
SAE technical paper series, Oct 5, 2022
SAE technical paper series, Oct 5, 2022
Open Circuit Potential (OCP) is the potential established between the working electrode (the meta... more Open Circuit Potential (OCP) is the potential established between the working electrode (the metallic surface to be studied) and the environment, with respect to a reference electrode, which will be placed in the electrolyte close to the working electrode. It is very important to measure the electric potentials of various metallic materials in order to know their corrosion behavior in various environments. But perhaps if there is brazing joint involved, as in the case of aluminium heat exchanger components, there are some challenges involved in knowing the potential of the fillet part which includes the selective masking of the areas within the same sample for testing. Firstly, getting reliable & accurate data due to masking process is one concern. Secondly, about the aluminium heat exchanger sample, the variation in OCP values within a single sample are possible due to various factors i.e. presence of cladding on the surface of the materials, presence of sacrificial Zn coating on the microtubes, variation in brazing parameters etc.In this study analytical correlation is made to OCP values of individual postbrazed child part samples w.r.t the entire brazed joint sample. This is being done in order to calculate & estimate the electric potential of the brazing fillet part. The individual currents at various areas within the sample w.r.t total specimen area are calculated & evaluated in order to arrive at a correlation between the observed potential vs. the sample area. From the obtained results it was found that the predicted theoretical fillet potential was in close agreement with the measured value. However, there is a scope of improvement in refining the simulation methods used in this study, in order to obtain more repeatable & accurate measurement OCP values.
SAE Technical Paper Series
D uring thermal performance testing, achieving thermal balance between two fluid mediums of any h... more D uring thermal performance testing, achieving thermal balance between two fluid mediums of any heat exchanger is critical. Heat balance ratio (HBR) measures the heat transfer imbalance between two sides (source and sink) in a heat exchanger and also helps in ensuring accuracy of test data. There could be many factors which may lead to the imbalance in thermal performance of the sample under testing e.g. sensors accuracy, test operating range, sample orientation, hysteresis in the data acquisition systems etc. Therefore, a testing procedure needs to be established to achieve a better heat balance ratio as low as less than ±5%, which accounts for errors during instrumentation processes, flow losses & manual errors during testing. The current experimental study focuses on a typical coolant aluminium brazed heater core product which is used in automotive applications for passenger cabin heating during the cold climate conditions, windshield demisting and defrosting. In this study, three geometrically different heater core samples have been tested inside the calorimeter bench for the measurement of thermal performance and heat balance ratio using the proposed methodology. Heater core inlet air temperature sensor was used for maintaining the inlet temperature parameter. Heater core inlet & outlet air temperature measurement was done using thermocouple (TC's) grid. Coolant side temperatures are measured using Resistance Temperature Detector (RTD) sensors. This methodology was validated for1:1 Ethylene Glycol+Water mixture and for tube and fin type heat exchanger. The currently existing testing methodologies exhibitHBR in the range of +10% to +30%, whilst the proposed method showed great improvement maintaining HBR less than ±5%& hence the new test method looks promising.
SAE Technical Paper Series
D uring the conventional brazing process of aluminium heat exchanger component (HEX), the tempera... more D uring the conventional brazing process of aluminium heat exchanger component (HEX), the temperature measurement of component in brazing furnace is a general requirement in order to control & achieve the required brazing temperature (around 590°C-610°C) to ensure efficient brazing joints of the aluminium products. The temperature measurement & monitoring during brazing is usually done with the help of temperature sensors alongwith the data logging system, in fact this is currently a widely used method. However, there are many drawbacks in this type of method for which a suitable solution needs to be developed. In this study, a possible development of simulation tool on the basis of data from Al-Si phase diagram & Lever rule, predicting the temperature on the component during brazing using this tool & comparing w.r.t actual measured data are discussed in detail. As a part of further validation, the data from both the data-logger as well as the estimated temperature from the simulation for the same sample at a specific defined location were compared and it was found that the simulated values were in close agreement with the measured values.
SAE Technical Paper Series
O pen Circuit Potential (OCP) is the potential established between the working electrode (the met... more O pen Circuit Potential (OCP) is the potential established between the working electrode (the metallic surface to be studied) and the environment, with respect to a reference electrode, which will be placed in the electrolyte close to the working electrode. It is very important to measure the electric potentials of various metallic materials in order to know their corrosion behavior in various environments. But perhaps if there is brazing joint involved, as in the case of aluminium heat exchanger components, there are some challenges involved in knowing the potential of the fillet part which includes the selective masking of the areas within the same sample for testing. Firstly, getting reliable & accurate data due to masking process is one concern. Secondly, about the aluminium heat exchanger sample, the variation in OCP values within a single sample are possible due to various factors i.e. presence of cladding on the surface of the materials, presence of sacrificial Zn coating on the microtubes, variation in brazing parameters etc. In this study analytical correlation is made to OCP values of individual postbrazed child part samples w.r.t the entire brazed joint sample. This is being done in order to calculate & estimate the electric potential of the brazing fillet part. The individual currents at various areas within the sample w.r.t total specimen area are calculated & evaluated in order to arrive at a correlation between the observed potential vs. the sample area. From the obtained results it was found that the predicted theoretical fillet potential was in close agreement with the measured value. However, there is a scope of improvement in refining the simulation methods used in this study, in order to obtain more repeatable & accurate measurement OCP values.
Rostfreie Stahllegierungen, Turboladerturbinengehäuse aus den rostfreien Stahllegierungen und Herstellungsverfahren dafür
Stainless steel alloys, turbocharger turbine housings formed from the stainless steel alloys, and... more Stainless steel alloys, turbocharger turbine housings formed from the stainless steel alloys, and methods for manufacturing the same (57) Disclosed is an austenitic stainless steel alloy that includes, by weight, about 16% to about 21% chromium, about 4.5% to about 5.5% nickel, about 2% to about 5% manganese, about 1% to about 2% silicon, about 0.8% to about 1.2% tungsten, about 0.4% to about 0.8% molybdenum, about 0.4% to about 0.6% niobium, about 0.4% to about 0.5% carbon, and a balance of iron. The alloy is suitable for use in turbocharger turbine housing applications for temperature up to about 1020°C.
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Papers by Praveen Guruprasanna (JSHL-R & D)