Investigation of the Relationship between Discharge – Pressure and Discharge- Temperature in the Conventional non-compensating and compensating Emitter tubes.

Background and objectives: Emitters discharge influenced by various factors such as pressure, manufacturing coefficient of variation, clogging or irrigation water temperature changes. Emitting pipes according to the hydraulic and technical specifications, the use of them in the trickle irrigation systems are increasing.Therefore investigation of the relationship between discharge – pressure and discharge- temperature is required in these pipes in order to improve the efficiency of trickle irrigation systems. Maroufpoor and Parvini(2012) fund with investigation of the relationship between discharge – pressure and discharge- temperature.That in all emitter and tested temperatures power of the discharge - pressure equation was less than 0.2 and all of were emitters pressure compensating. The effect of temperature on the discharge 3 emitter at 95 percent significant and was non-significant other emitters.
Materials and Methods: In order to evaluate the effect of temperature and pressure on emitters discharge, 8 emitting pipe, 6 type of non-compensating and 2 compensating was tested on the constructed physical model of drip irrigation in the water laboratory of University of Kurdistan. In each experiment, according to the standard on every model from the emitting pipes slices, 25 slices were selected randomly. Each slices was consists of 5 units emitters. Slices length varied proportional to the distance of unit’s emitters in the range of 2 to 5 m. The effects of four different water temperatures (13, 23, 33 and 43°C) with different pressure ranges (between zero and 1.2 times more than the maximum pressure) on the emitters were evaluated. The thermostat and element were used to supply water temperatures of 23, 33 and 43 ° C. To supply water temperatures 13 ° C was used of the ice pieces. Generally in the every temperature, discharge of compensating emitting pipes was measured at 10 pressures and in the non-compensating emitting pipes was measured at 7 pressures. Data analysis was performed in a randomized complete block design using SAS software.
Results:According to the results obtained from the experiments of discharge- pressure at all temperatures, in the both C1 and C4 emitting pipes, power of the discharge - pressure equation was less than 0.2,therefore, as compensating are acceptable and were good degree of them flexibility. As well as in the rest of the emitting pipes power of equation was variable between 0.2 and 1 and as non-compensating and them flexibility was the high degree of flexibility. According to the results obtained from the experiments discharge – temperature, in the all emitting pipes of non-compensating, the effect of temperature on discharge at 95 percent was significant, that generally discharge had increased with increasing temperature. In the compensating emitting pipes with increasing temperature from 13 °C to 23 °C, flow rate has increased at 95 percent significantly, but from temperature of 23 °C to temperature 43 °C there was no significant difference between emitters discharge.
Conclusion: In general it can be concluded that the relationship discharge – pressure in the external and internal emitting pipes of common market is acceptable and desirable. Also is suggested that, in the design of trickle irrigation systems that is used emitting pipes, was ensured the effect of temperature on the discharge of emitting pipes units and the necessary correction coefficients is applied emitter nominal flow rate.