On the Quasi-Steadiness Hypothesis as Applied to Gas Exhaustion from a Receiver

Comparative Analysis of Methods for Measuring the Transient Burning Rate. I. Research Methods

“…Known versions of this method use the hypothesis of flow quasistationarity during opening of a secondary nozzle for depressurization and subsequent propellant extinguishment [13]. The present paper proposes a method for measuring the transient burning rate taking into account unsteady flow in the transient process [19].…”

Transient flow characteristics of a high speed rotary valve

“…Glass suggests the following definitions: The next significant event in the shock tube occurs when the shock wave is reflected at the closed end of the tube, as represented in Figure 13. It is at the tube end that the velocity of fluid moving in region 2 must necessarily be brought to rest to maintain zero wall velocity after the reflected shock moves back into region 2 ( 5 0 u = ) and the pressure ratio can be solved according to The time required to allow the starting shock to clear the initial length of the tube, t S1,RFL , has been successfully used in literature as one of the characteristic times governing real fluid systems that have been modeled numerically [31,35].…”

“…In Figure 19, the strengthened shock S 4 reaches the end of the tube and is reflected back into region 11. Arkhipov et al [31], only the longest of either t R1,RFL or t S1,RFL is used to establish the final time for an exponential flow rate increase from zero up to the quasi-steady flow rate which has been measured or adjusted from theory by some experimentally determined discharge coefficient.…”

“…The established mass flow rate can then be compared to the theoretical mass flow rate for the CCV to identify the CCV discharge coefficient. It is worth noting thatYoon et al [114] published the formula for the wedge shaped area of the flow meter as wedge-to-pipe area ratio, m, is given as the somewhat reversed situation of the research of Gault et al, Arkhipov et al[31] have investigated the quasi-steady behavior of gas exhaust from a receiver, the likes of which might be found aboard space vehicles for the purpose of attitude microadjustments. Beginning with a hypothetical thermally insulated pressure tank, a valve is quickly (though not instantaneously) opened to allow gas exhaustion to occur.…”

“…The first rarefaction zone (R 1 ) is reflected at the end of the closed tube.The time required for region 6 to reach steady conditions is another key time used in literature to develop experimental and numerical models[31,35]. According to Glass, the dimensionless time constant of interest with regard to the formation of a steady region 6 for a diatomic gas is found as an example showing that for P 41 = 10.5, L = 1 ft., T 1 = 72°F, t R1,RFL = 3.82 milliseconds.…”