Effect of catalytic bed porosity and mass flow rate on decomposition and combustion processes of a HAN-Based monopropellant thruster

2021 ◽

Author(s):

Prashant Verma ◽

Abhishek Saxena ◽

L. Varshney

Keyword(s):

Heat Transfer ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Hydraulic Performance ◽

Major Influence ◽

Pumping Power ◽

Bed Porosity ◽

Wire Screen ◽

The Impact

Solar air heaters (SAHs) have an important role in applications such as space heating and industrial drying worldwide. The packing of SAH bed not only increases the heat transfer area but also increases the pumping power losses thereby limiting the thermo-hydraulic performance. In the present study, efforts have been made for a critical assessment of the literature dealing with the impact of collector bed and operating parameters over thermal and thermo-hydraulic performance for different configurations of wire screen matrix packed SAH. The porosity of bed and mass flow rate of the air have a major influence on the thermo-hydraulic performance of wire screen matrix packed SAH. It is found that the enhancement in the volumetric heat transfer coefficient due to a decrease in bed porosity is obtained at the expense of increase in pumping power which ultimately affects the thermo-hydraulic performance of wire screen matrix packed SAH. In general it is observed that porosity is an important parameter that affects the thermo-hydraulic performance. It is seen that matrix having porosity 0.937 yields thermo-hydraulic performance of 68% at mass flow rate 0.023 kg/s where as for the same mass flow rate porosity of 0.887 results thermo-hydraulic performance of only 42%.

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Effect of Injection Pressure, Injection Duration, and Injection Frequency on Direct Injector’s Mass Flow Rate for Compressed Natural Gas Fuel

MATEC Web of Conferences ◽

10.1051/matecconf/201822502008 ◽

2018 ◽

Vol 225 ◽

pp. 02008

Author(s):

Mohamad Hafizul Rahman Alias ◽

Mohd Fadzil Abdul Rahim ◽

Muhamad Haziq Mohd Ismail Rodzi ◽

Rosli Abu Bakar

Keyword(s):

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Theoretical Calculations ◽

Injection Pressure ◽

Compressed Natural Gas ◽

Injection Duration ◽

Injection Frequency ◽

Gas Fuel ◽

Combustion Processes

A conventional gasoline direct injector is converted for gaseous fuel application. The conversion alters the injector characteristic which further affect the mixture formation and combustion processes. The purpose of this study is to investigate the effects of injection pressure (case 1), injection duration (case 2), and injection frequency (case 3) on the injector’s mass flow rate. An injector was independently tested by using an injector test bench. In Case 1, the injection pressure was tested from 20 bar to 60 bar at 24 ms of injection duration for 1000 injection counts. In Case 2, the injection duration was set from 2 to 24 ms at a constant 50 bar injection pressure for different engine speed. Whereas in Case 3, the averaged mass flow rate are plotted at different injection frequency. Theoretical calculations were carried out to compare the experimental and theoretical result. The experiment results shown that the injection pressure affected the injector mass flow rate linearly. At short injection duration, the mass flow rate inconsistent and highly fluctuated. At higher injection frequency, the mass flow rate is becoming higher. The theoretical results able to predict the mass flow rate trend but were unable to spot the fluctuating effects.

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