Minimum Straight Run constraints in flow meter

I want to install a flowmeter for liquid ethylene with temp around -96 degc, what type is the best flow meter for minimum straight run installation than can be installed in location that has around 4D ( nominal diameter of pipe) in upstream of flow meter with knowing that we already have vortex type flow meter but it does not work because of this issue?
Check out Veris Accelabar which uses proprietary nozzle and pitot technology for flow conditioning so that it needs no upstream or downstream flow conditioning. Wide turndowns require multiple DP transmitters. I do not know how low temperatures are handled (more on the DP sampling side than the mechanical flow side), but you can inquire to see what they have to say.®